This is a write-up of each of the emulated synthesisers. The algorithms employed were 'gleaned' from a variety of sources including the original owners manuals, so they may be a better source of information. The author has owned and used a selection but far from all of the originals. Some of them were built just from descriptions of their operation, or from understanding how synths work - most of them were based on the Mini Moog anyway. Many of the synths share components: the filter covers most of them, the Prophets and Oberheims share a common oscillator and the same LFO is used in many of them. Having said that each one differs considerably in the resulting sound that is generated, more so than initially expected. Each release refines each of the components and the result is that all emulations benefit from the improvements. All the emulations have distinctive sounds, not least due to that the original instruments used different modulations and mod routing. The filter, which is a large defining factor in the tonal qualities of any synth, is common to all the emulations. The filter implements a few different algorithms and these do separate each of the synths: the Explorer layering two low pass filters on top of each other: the OB-Xa using different types depending on 'Pole' selection. Since release 0.20.8 the emulator has had a Huovilainen non-linear ladder filter integrated which massively improves the quality at considerable expense to the CPU. There is one further filter algorithm used solely for the Leslie rotary emulator crossover, this is a butterworth type filter.
Bristol is in no way related to any of the original manufacturers whose products are emulated by the engine and represented by the user interface, bristol does not suggest that the emulation is a like representation of the original instrument, and the author maintains that if you want the original sound then you are advised to seek out the original product. Alternatively a number of the original manufacturers now provide their own vintage collections which are anticipated to be more authentic. All names and trademarks used by Bristol are ownership of the respective companies and it is not intended to misappropriate their use here. If you have concerns you are kindly requested to contact the author.
The write-up includes the parameter operations, modulations, a description of the original instrument and a brief list of the kind of sounds you can expect by describing a few of the well known users of the synth.
Several emulations have not been written up. Since the APR 2600 was implemented it became a rather large job to actually describe what was going on. If you really want to know about the synths that are not in this document then you might want to search for their owners manuals.
All emulations are available from the same engine, just launch multiple GUIs and adjust the MIDI channels for multitimbrality and layering.
It is noted here that the engine is relatively 'dumb'. Ok, it generates a very broad range of sounds, currently about 25 different synthesisers and organs, but it is not really intelligent. Memories are a part of the GUI specification
Since release 0.30.6 the engine correctly implements monophonic note logic. Prior to this the whole engine was polyphonic and playing with one voice only gave last note preference which dramatically affects playing styles - none of the cool legato effects of the early monophonics. The quoted release fix this limitation where the engine will keep a keymap of all played keys (one per emulation) when started with a single voice and uses this map to provide consistent note precedence, high note logic, low note logic or just using the previously implemented last note logic. In this release the keymap was only maintained with monophonic emulations, this is a potential extension as even in polyphonic mode it would be useful for arpeggiation (which is currently implemented using a FIFO rather than an ordered keymap).
Moog Mini
---------It is perhaps not possible to write up who used this synth, the list is endless. Popular as it was about the first non-modular synthesiser, built as a fixed configuration of the racked or modular predecessors.
Best known at the time on Pink Floyd 'Dark Side of the Moon' and other albums. Rick Wakeman used it as did Jean-Michel Jarre. Wakefield could actually predict the sound it would make by just looking at the settings, nice to be able to do if a little unproductive but it went to show how this was treated as an instrument in its own right. It takes a bit of work to get the same sweet, rich sounds out of the emulation, but it can be done with suitable tweaking.
The original was monophonic, although a polyphonic version was eventually made after Moog sold the company - the MultiMoog. This emulation is more comparable to that model as the sound is a bit thinner and can be polyphonic. The design of this synth became the pole bearer for the following generations: it had three oscillators, one of which could become a low frequency modulator. They were fed into a mixer with a noise source, and were then fed into a filter with 2 envelope generators to contour the wave. Modulation capabilities were not extensive, but interestingly enough it did have a frequency modulation (FM) capability, eventually used by Yamaha to revolutionise the synthesiser market starting the downfall of analogue synthesis twenty years later.
All the analogue synths were temperature sensitive. It was not unusual for the synths to 'detune' between sound test and performance as the evening set in. To overcome this they could optionally produce a stable A-440Hz signal for tuning the oscillators manually - eventually being an automated option in the newer synths. Whilst this digital version has stable frequency generation the A-440 is still employed here for the sake of it.
Modifiers and mod routing are relatively simple, Osc-3 and noise can be mixed, and this signal routed to the oscillator 1 and 2 frequency or filter cutoff.
The synth had 5 main stages as follows:
Control:
Master tuning: up/down one note.
Glide: (glissando, portamento). The rate at which one key will change its
frequency to the next played key, 0 to 30 seconds.
Mod: source changes between Osc-3 and noise.
Release: The envelope generators had only 3 parameters. This governed whether
a key would release immediately or would use Decay to die out.
Multi: Controls whether the envelope will retrigger for each new keypress.Oscillators:
There are three oscillators. One and two are keyboard tracking, the third
can be decoupled and used as an LFO modulation source.
Oscillator 1:
Octave step from 32' to 1'.
Waveform selection: sine/square/pulse/ramp/tri/splitramp
Mod: controls whether Osc-3/noise modulates frequency
Oscillator 2:
Octave step from 32' to 1'.
Fine tune up/down 7 half notes.
Waveform selection: sine/square/pulse/ramp/tri/splitramp
Mod: controls whether Osc-3/noise modulates frequency
Oscillator 3:
Octave step from 32' to 1'.
Fine tune up/down 7 half notes.
Waveform selection: sine/square/pulse/ramp/tri/splitramp
LFO switch to decouple from keytracking.Mixer:
Gain levels for Oscillator 1/2/3
Mixing of the external input source into filter
Noise source with white/pink switch.
Note: The level at which Osc-3 and noise modulates sound depends on its
gain here, similarly the noise. The modulator mix also affects this, but
allows Osc-3 to mod as well as sound. The modwheel also affect depth.Filter:
Cutoff frequency
Emphasis (affects Q and resonance of filter).
Contour: defines how much the filter envelope affects cutoff.
Mod - Keyboard tracking of cutoff frequency.
Mod - Osc-3/noise modulation of cutoff frequency.Contour:
The synth had two envelope generators, one for the filter and one for the
amplifier. Release is affected by the release switch. If off the the sound
will release at the rate of the decay control.
Attack: initial ramp up of gain.
Decay: fall off of maximum signal down to:
Sustain: gain level for constant key-on level.
Key: Touch sensitivity of amplifier envelope.Improvements to the Mini would be some better oscillator waveforms, plus an alternative filter as this is a relatively simple synthesiser and could do with a warmer filter (this was fixed with integration of the Huovilainen filters although the do consume a lot of CPU to do it).
The Output selection has a MIDI channel up/down selector and memory selector. To read a memory either use the up/down arrows to go to the next available memory, or type in a 3 digit number on the telephone keypad and press 'L' for load or 'S' for save.
As of release 0.20.5 Vasiliy Basic contributed his Mini memory banks and they are now a part of the distribution:
Programs for Bristol's "Mini" (from 50 to 86 PRG)
List of programs:
-Melodic-
50 - Trumpet
51 - Cello
52 - Guitar 1
53 - Guitar 2
54 - Fingered Bass
55 - Picked Bass
56 - Harmonica
57 - Accordion
58 - Tango Accordion
59 - Super Accordion
60 - Piano
61 - Dark Organ
62 - Flute
63 - Music Box
64 - Glass Xylo
65 - Glass Pad
66 - Acid Bass
-Drums-
67 - Bass Drum 1
68 - Bass Drum 2
69 - Bass Drum 3
70 - Bass Drum 4
71 - Tom
72 - Snare 1
73 - Snare 2
74 - Snare 3
75 - Snare 4
76 - Cl HH 1
77 - Op HH 1
78 - Crash Cym 1
79 - Crash Cym 2
80 - Cl HH 2
81 - Op HH 2
-FX-
82 - Sea Shore
83 - Helicopter 1
84 - Helicopter 2
85 - Bird Tweet
86 - Birds Tweet
Sequential Circuits Prophet-5
Sequential Circuits Prophet-52 (the '5' with chorus)
----------------------------------------------------Sequential circuits released amongst the first truly polyphonic synthesisers where a group of voice circuits (5 in this case) were linked to an onboard computer that gave the same parameters to each voice and drove the notes to each voice from the keyboard. The device had some limited memories to allow for real live stage work. The synth was amazingly flexible regarding the oscillator options and modulation routing, producing some of the fattest sounds around. They also had some of the fattest pricing as well, putting it out of reach of all but the select few, something that maintained its mythical status. David Sylvian of Duran Duran used the synth to wide acclaim in the early 80's as did many of the new wave of bands.
The -52 is the same as the -5 with the addition of a chorus as it was easy, it turns the synth stereo for more width to the sound, and others have done it on the Win platform.
The design of the Prophet synthesisers follows that of the Mini Moog. It has three oscillators one of them as a dedicated LFO. The second audio oscillator can also function as a second LFO, and can cross modulate oscillator A for FM type effects. The audible oscillators have fixed waveforms with pulse width modulation of the square wave. These are then mixed and sent to the filter with two envelopes, for the filter and amplifier.
Modulation bussing is quite rich. There is the wheel modulation which is global, taking the LFO and Noise as a mixed source, and send it under wheel control to any of the oscillator frequency and pulse width, plus the filter cutoff. Poly mods take two sources, the filter envelope and Osc-B output (which are fully polyphonic, or rather, independent per voice), and can route them through to Osc-A frequency and Pulse Width, or through to the filter. To get the filter envelope to actually affect the filter it needs to go through the PolyMod section. Directing the filter envelope to the PW of Osc-A can make wide, breathy scanning effects, and when applied to the frequency can give portamento effects.
LFO:
Frequency: 0.1 to 50 Hz
Shape: Ramp/Triangle/Square. All can be selected, none selected should
give a sine wave (*)
(*) Not yet implemented.Wheel Mod:
Mix: LFO/Noise
Dest: Osc-A Freq/Osc-B Freq/Osc-A PW/Osc-B PW/Filter CutoffPoly Mod: These are affected by key velocity.
Filter Env: Amount of filter envelope applied
Osc-B: Amount of Osc-B applied:
Dest: Osc-A Freq/Osc-A PW/Filter CutoffOsc-A:
Freq: 32' to 1' in octave steps
Shape: Ramp or Square
Pulse Width: only when Square is active.
Sync: synchronise to Osc-BOsc-B:
Freq: 32' to 1' in octave steps
Fine: +/- 7 semitones
Shape: Ramp/Triangle/Square
Pulse Width: only when Square is active.
LFO: Lowers frequency by 'several' octaves.
KBD: enable/disable keyboard tracking.Mixer:
Gain for Osc-A, Osc-B, NoiseFilter:
Cutoff: cuttof frequency
Res: Resonance/Q/Emphasis
Env: amount of PolyMod affecting to cutoff.Envelopes: One each for PolyMod (filter) and amplifier.
Attack
Decay
Sustain
ReleaseGlobal:
Master Volume
A440 - stable sine wave at A440 Hz for tuning.
MIDI: channel up/down
Release: release all notes
Tune: autotune oscillators.
Glide: amount of portamento
Unison: gang all voices to a single 'fat' monophonic synthesiser.This is one of the fatter of the Bristol synths and the design of the mods is impressive (not my design, this is as per sequential circuits spec). Some of the cross modulations are noisy, notably 'Osc-B->Freq Osc-A' for square waves as dest and worse as source.
The chorus used by the Prophet-52 is a stereo 'Dimension-D' type effect. The signal is panned from left to right at one rate, and the phasing and depth at a separate rate to generate subtle chorus through to helicopter flanging.
Memories are loaded by selecting the 'Bank' button and typing in a two digit bank number followed by load. Once the bank has been selected then 8 memories from the bank can be loaded by pressing another memory select and pressing load. The display will show free memories (FRE) or programmed (PRG).
Yamaha DX-7
-----------Released in the '80s this synth quickly became the most popular of all time. It was the first fully digital synth, employed a revolutionary frequency modulated algorithm and was priced much lower than the analogue monsters that preceded it. Philip Glass used it to wide effect for Miami Vice, Prince had it on many of his albums, Howard Jones produced albums filled with its library sounds. The whole of the 80's were loaded with this synth, almost to the point of saturation. There was generally wide use of its library sounds due to the fact that it was nigh on impossible to programme, only having entry buttons and the algorithm itself was not exactly intuitive, but also because the library was exceptional and the voices very playable. The emulation is a 6 operator per voice, and all the parameters are directly accessible to ease programming.
The original DX had six operators although cheaper models were release with just 4 operators and a consequently thinner sound. Each operator is a sine wave oscillator with its own envelope generator for amplification and a few parameters that adjusted its modulators. It used a number of different algorithms where operators were mixed together and then used to adjust the frequency of the next set of operators. The sequence of the operators affected the net harmonics of the overall sound. Each operator has a seven stage envelope - 'ramp' to 'level 1', 'ramp' to 'level 2', 'decay' to 'sustain', and finally 'release' when a key is released. The input gain to the frequency modulation is controllable, the output gain is also adjustable, and the final stage operators can be panned left and right.
Each operator has:
Envelope:
Attack: Ramp rate to L1
L1: First target gain level
Attack: Ramp rate from L2 to L2
L2: Second target gain level
Decay: Ramp rate to sustain level
Sustain: Continuous gain level
Release: Key release ramp rate
Tuning:
Tune: +/- 7 semitones
Transpose: 32' to 1' in octave increments
LFO: Low frequency oscillation with no keyboard control
Gain controls:
Touch: Velocity sensitivity of operator.
In gain: Amount of frequency modulation from input
Out gain: Output signal level
IGC: Input gain under Mod control
OGC: Output gain under Mod control
Pan: L/R pan of final stage operators.Global and Algorithms:
24 different operator staging algorithms
Pitchwheel: Depth of pitch modifier
Glide: Polyphonic portamento
Volume
Tune: Autotune all operatorsMemories can be selected with either submitting a 3 digit number on the keypad, or selecting the orange up/down buttons.
An improvement could be more preset memories with different sounds that can then be modified, i.e., more library sounds. There are some improvements that could be made to polyphonic mods from key velocity and channel/poly pressure that would not be difficult to implement.
The addition of triangle of other complex waveforms could be a fun development effort (if anyone were to want to do it).
The DX still has a prependency to segfault, especially when large gains are applied to input signals. This is due to loose bounds checking that will be extended in a present release.
Roland Juno-60
--------------Roland was one of the main pacemakers in analogue synthesis, also competing with the Sequential and Oberheim products. They did anticipate the moving market and produced the Juno-6 relatively early. This was one of the first accessible synths, having a reasonably fat analogue sound without the price card of the monster predecessors. It brought synthesis to the mass market that marked the decline of Sequential Circuits and Oberheim who continued to make their products bigger and fatter. The reduced price tag meant it had a slightly thinner sound, and a chorus was added to extend this, to be a little more comparable.
The synth again follows the Mini Moog design of oscillators into filter into amp. The single oscillator is fattened out with harmonics and pulse width modulation. There is only one envelope generator that can apply to both the filter and amplifier.
Control:
DCO: Amount of pitch wheel that is applied to the oscillators frequency.
VCF: Amount of pitch wheel that is applied to the filter frequency.
Tune: Master tuning of instrument
Glide: length of portamento
LFO: Manual control for start of LFO operation.Hold: (*)
Transpose: Up/Down one octave
Hold: prevent key off eventsLFO:
Rate: Frequency of LFO
Delay: Period before LFO is activated
Man/Auto: Manual or Automatic cut in of LFODCO:
LFO: Amount of LFO affecting frequency. Affected by mod wheel.
PWM: Amount of LFO affecting PWM. Affected by mod wheel.
ENV/LFO/MANUAL: Modulator for PWM
Waveform:
Pulse or Ramp wave. Pulse has PWM capability.
Sub oscillator:
On/Off first fundamental square wave.
Sub:
Mixer for fundamental
Noise:
Mixer of white noise source.HPF: High Pass Filter
Freq:
Frequency of cutoff.VCF:
Freq:
Cutoff frequency
Res:
Resonance/emphasis.
Envelope:
+ve/-ve application
Env:
Amount of contour applied to cutoff
LFO:
Depth of LFO modulation applied.
KBD:
Amount of key tracking applied.VCA:
Env/Gate:
Contour is either gated or modulated by ADSR
Level:
Overall volumeADSR:
Attack
Decay
Sustain
ReleaseChorus:
8 Selectable levels of Dimension-D type helicopter flanger.The LFO cut in and gain is adjusted by a timer and envelope that it triggers.
The Juno would improve from the use of the prophet DCO rather than its own one. It would require a second oscillator for the sub frequency, but the prophet DCO can do all the Juno does with better resampling and PWM generation.
Moog Voyager (Bristol "Explorer")
---------------------------------This was Robert Moog's last synth, similar in build to the Mini but created over a quarter of a century later and having far, far more flexibility. It was still monophonic, a flashback to a legendary synth but also a bit like Bjorn Borg taking his wooden tennis racket back to Wimbledon long after having retired and carbon fibre having come to pass. I have no idea who uses it and Bjorn also crashed out in the first round. The modulation routing is exceptional if not exactly clear.
The Voyager, or Bristol Explorer, is definitely a child of the Mini. It has the same fold up control panel, three and half octave keyboard and very much that same look and feel. It follows the same rough design of three oscillators mixed with noise into a filter with envelopes for the filter and amplifier. In contrast there is an extra 4th oscillator, a dedicated LFO bus also Osc-3 can still function as a second LFO here. The waveforms are continuously selected, changing gradually to each form: bristol uses a form of morphing get get similar results. The envelopes are 4 stage rather than the 3 stage Mini, and the effects routing bears no comparison at all, being far more flexible here.
Just because its funny to know, Robert Moog once stated that the most difficult part of building and releasing the Voyager was giving it the title 'Moog'. He had sold his company in the seventies and had to buy back the right to use his own name to release this synthesiser as a Moog, knowing that without that title it probably would not sell quite as well as it didn't.
Control:
LFO:
Frequency
Sync: LFO restarted with each keypress.
Fine tune +/- one note
Glide 0 to 30 seconds.Modulation Busses:
Two busses are implemented. Both have similar capabilities but one is
controlled by the mod wheel and the other is constantly on. Each bus has
a selection of sources, shaping, destination selection and amount.
Wheel Modulation: Depth is controller by mod wheel.
Source: Triwave/Ramp/Sample&Hold/Osc-3/External
Shape: Off/Key control/Envelope/On
Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
Amount: 0 to 1.
Constant Modulation: Can use Osc-3 as second LFO to fatten sound.
Source: Triwave/Ramp/Sample&Hold/Osc-3/External
Shape: Off/Key control/Envelope/On
Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
Amount: 0 to 1.
* Destination of filter is the cutoff frequency. Filter space is the
difference in cutoff of the two layered filters. Waveform destination
affects the continuously variable oscillator waveforms and allows for
Pulse Width Modulation type effects with considerably more power since
it can affect ramp to triangle for example, not just pulse width.Oscillators:
Oscillator 1:
Octave: 32' to 1' in octave steps
Waveform: Continuous between Triangle/Ramp/Square/Pulse
Oscillator 2:
Tune: Continuous up/down 7 semitones.
Octave: 32' to 1' in octave steps
Waveform: Continuous between Triangle/Ramp/Square/Pulse
Oscillator 3:
Tune: Continuous up/down 7 semitones.
Octave: 32' to 1' in octave steps
Waveform: Continuous between Triangle/Ramp/Square/Pulse
Sync: Synchronise Osc-2 to Osc-1
FM: Osc-3 frequency modulates Osc-1
KBD: Keyboard tracking Osc-3
Freq: Osc-3 as second LFOMixer:
Gain levels for each source: Osc-1/2/3, noise and external input.Filters:
There are two filters with different configuration modes:
1. Two parallel resonant lowpass filters.
2. Serialised HPF and resonant LPF
Cutoff: Frequency of cutoff
Space: Distance between the cutoff of the two filters.
Resonance: emphasis/Q.
KBD tracking amount
Mode: Select between the two operating modes.Envelopes:
Attack
Decay
Sustain
Release
Amount to filter (positive and negative control)
Velocity sensitivity of amplifier envelope.Master:
Volume
LFO: Single LFO or one per voice (polyphonic operation).
Glide: On/Off portamento
Release: On/Off envelope release.The Explorer has a control wheel and a control pad. The central section has the memory section plus a panel that can modify any of the synth parameters as a real time control. Press the first mouse key here and move the mouse around to adjust the controls. Default values are LFO frequency and filter cutoff but values can be changed with the 'panel' button. This is done by selecting 'panel' rather than 'MIDI', and then using the up/down keys to select parameter that will be affected by the x and y motion of the mouse. At the moment the mod routing from the pad controller is not saved to the memories, and it will remain so since the pad controller is not exactly omnipresent on MIDI master keyboards - the capabilities was put into the GUI to be 'exact' to the design.
This synth is amazingly flexible and difficult to advise on its best use. Try starting by mixing just oscillator 1 through to the filter, working on mod and filter options to enrich the sound, playing with the oscillator switches for different effects and then slowly mix in oscillator 2 and 3 as desired.
Memories are available via two grey up/down selector buttons, or a three digit number can be entered. There are two rows of black buttons where the top row is 0 to 4 and the second is 5 to 9. When a memory is selected the LCD display will show whether it is is free (FRE) or programmed already (PRG).
The author first implemented the Hammond module, then extended it to the B3 emulation. Users of this are too numerous to mention and the organ is still popular. Jimmy Smith, Screaming Jay Hawkins, Keith Emerson, Doors and almost all American gospel blues. Smith was profuse, using the instrument for a jazz audience, even using its defects (key noise) to great effect. Emerson had two on stage, one to play and another to kick around, even including stabbing the keyboard with a knife to force keylock during performances (Emerson was also a Moog fan with some of the first live performances). He also used the defects of the system to great effect, giving life to the over- driven Hammond sound.
The Hammond was historically a mechanical instrument although later cheaper models used electronics. The unit had a master motor that rotated at the speed of the mains supply. It drove a spindle of cog wheels and next to each cog was a pickup. The pickup output went into the matrix of the harmonic drawbars. It was originally devised to replace the massive pipe organs in churches - Hammond marketed their instruments with claims that they could not be differentiated from the mechanical pipe equivalent. He was taken to court by the US government for misrepresentation, finally winning his case using a double blind competitive test against a pipe organ, in a cathedral, with speakers mounted behind the organ pipes and an array of music scholars, students and professionals listening. The results spoke for themselves - students would have scored better by simply guessing which was which, the professionals fared only a little better than that. The age of the Hammond organ had arrived.
The company had a love/hate relationship with the Leslie speaker company - the latter making money by selling their rotary speakers along with the organ to wide acceptance. The fat Hammond 'chorus' was a failed attempt to distance themselves from Leslie. That was never achieved due to the acceptance of the Leslie, but the chorus did add another unique sound to the already awesome instrument. The rotary speaker itself still added an extra something to the unique sound that is difficult imagine one without the other. It has a wide range of operating modes most of which are included in this emulator.
The chorus emulation is an 8 stage phase shifting filter algorithm with a linear rotor between the taps.
Parametrisation of the first B3 window follows the original design:
Leslie: Rotary speaker on/off
Reverb: Reverb on/off
VibraChorus: 3 levels of vibrato, 3 of chorus.
Bright: Added upper harmonics to waveforms.Lower and Upper Manual Drawbars: The drawbars are colour coded into white for even harmonics and black for odd harmonics. There are two subfrequencies in brown. The number given here are the length of organ pipe that would correspond to the given desired frequency.
16 - Lower fundamental
5 1/3 - Lower 3rd fundamental
8 - Fundamental
4 - First even harmonic
2 2/3 - First odd harmonic
2 - Second even harmonic
1 3/5 - Second odd harmonic
1 1/3 - Third odd harmonic
1 - Third even harmonicThe drawbars are effectively mixed for each note played. The method by which the mixing is done is controlled in the options section below. There were numerous anomalies shown by the instrument and most of them are emulated.
The Hammond could provide percussives effect the first even and odd harmonics. This gave a piano like effect and is emulated with Attack/Decay envelope.
Perc 4' - Apply percussive to the first even harmonic
Perc 2 2/3' - Apply percussive to the first odd harmonic
Slow - Adjust rate of decay from about 1/2 second to 4 seconds.
Soft - Provide a soft attack to each note.The soft attack is an attempt to reduce the level of undesired key noise. The keyboard consisted of a metal bar under each key that made physical contact with 9 sprung teeth to tap off the harmonics. The initial contact would generate noise that did not really accord to the pipe organ comparison. This was reduced by adding a slow start to each key, but the jazz musicians had used this defect to great effect, terming it 'key click' and it became a part of the Hammond characteristics. Some musicians would even brag about how noisy there organ was.
On the left had side are three more controls:
Volume potentiometer
Options switch discussed below.
Rotary Speed: low/high speed Leslie rotation. Shifts between the speeds
are suppressed to emulate the spin up and down periods of the leslie motors.The options section, under control of the options button, has the parameters used to control the emulation. These are broken into sections and discussed individually.
Leslie:
The Leslie rotary speaker consisted of a large cabinet with a bass speaker and a pair of high frequency air horns. Each were mounted on its own rotating table and driven around inside the cabinet by motors. A crossover filter was used to separate the frequencies driven to either speaker. Each pair was typically isolated physically from the other. As the speaker rotated it would generate chorus type effects, but far richer in quality. Depending on where the speaker was with respect to the listener the sound would also appear to rotate. There would be different phasing effects based on signal reflections, different filtering effects depending on where the speaker was in respect to the cabinet producing differences resonances with respect to the internal baffling.
Separate:
Sync:
No Bass:
The Leslie had two motors, one for the horns and one for the voice coil
speaker. These rotated at different speeds. Some players preferred to
have both rotate at the same speed, would remove the second motor and
bind the spindles of each speaker table, this had the added effect
that both would also spin up at the same rate, not true of the
separated motors since each table had a very different rotary moment.
The 'No Bass' option does not rotate the voice coil speaker. This was
typically done since it would respond only slowly to speed changes,
this left just the horns rotating but able to spin up and down faster.
Brake:
Some cabinets had a brake applied to the tables such that when the
motor stopped the speakers slowed down faster.
X-Over:
This is the cross over frequency between the voice coil and air horns.
Uses a butterworth filter design.
Inertia:
Rate at which speaker rotational speed will respond to changes.
Overdrive:
Amount by which the amplifier is overdriven into distortion.
H-Depth/Frequency/Phase
L-Depth/Frequency/Phase
These parameters control the rotary phasing effect. The algorithm used
has three differently phased rotations used for filtering, phasing and
reverberation of the sound. These parameters are used to control the
depth and general phasing of each of them, giving different parameters
for the high and low speed rotations. There are no separate parameters
for the voice coil or air horns, these parameters are for the two
different speeds only, although in 'Separate' mode the two motors will
rotate at slightly different speeds.Chorus
V1/C1 - Lowest chorus speed
V2/C2 - Medium chorus speed
V3/C3 - High chorus speedPercussion:
Decay Fast/Slow - controls the percussive delay rates.
Attack Slow Fast - Controls the per note envelope attack time.The percussives are emulated as per the original design where there was a single envelope for the whole keyboard and not per note. The envelope will only restrike for a cleanly pressed note.
Finally there are several parameters affecting the sine wave generation code. The Hammond used cogged wheels and coil pickups to generate all the harmonics, but the output was not a pure sine wave. This section primarily adjusts the waveform generation:
Preacher:
The emulator has two modes of operation, one is to generate the
harmonics only for each keyed note and another to generate all of
them and tap of those required for whatever keys have been pressed.
Both work and have different net results. Firstly, generating each
note independently is far more efficient than generating all 90 odd
teeth, as only a few are typically required. This does not have totally
linked phases between notes and cannot provide for signal damping (see
below).
The Preacher algorithm generates all harmonics continuously as per the
original instrument. It is a better rendition at the expense of large
chunks of CPU activity. This is discussed further below.
Compress:
Time compress the sine wave to produce a slightly sharper leading edge.
Bright:
Add additional high frequency harmonics to the sine.
Click:
Level of key click noise
Reverb:
Amount of reverb added by the Leslie
Damping:
If the same harmonic was reused by different pressed keys then its net
volume would not be a complete sum, the output gain would decay as the
pickups would become overloaded. This would dampen the signal strength.
This is only available with the Preacher algorithm.The two reverse octaves are presets as per the original, however here they can just be used to recall the first 23 memories of the current bank. The lower manual 12 key is the 'save' key for the current settings and must be double clicked. It should be possible to drive these keys via MIDI, not currently tested though. The default presets are a mixture of settings, the lower manual being typical 'standard' recital settings, the upper manual being a mixture of Smith, Argent, Emerson, Winwood and other settings from the well known Hammond Leslie FAQ. You can overwrite them. As a slight anomaly, which was intentional, loading a memory from the these keys only adjusts the visible parameters - the drawbars, leslie, etc. The unseen ones in the options panel do not change. When you save a memory with a double click on the lower manual last reverse key then in contrast it saves all the parameters. This will not change.
The Preacher algorithm supports a diverse set of options for its tonewheel emulation. These are configured in the file $BRISTOL/memory/profiles/tonewheel and there is only one copy. The file is a text file and will remain that way, it is reasonably documented in the file itself. Most settings have two ranges, one representing the normal setting and the other the bright setting for when the 'bright' button is pressed. The following settings are currently available:
ToneNormal: each wheel can be given a waveform setting from 0 (square)
through to 1.0 (pure sine) to X (sharpening ramp).
EQNormal: each wheel can be given a gain level across the whole generator.
DampNormal: each wheel has a damping factor (level robbing/damping/stealing)
BusNormal: each drawbar can be equalised globally.
ToneBright: each wheel can be given a waveform setting from 0 (square)
through to 1.0 (pure sine) to X (sharpening ramp) for the bright button.
EQBright: each wheel can be given a gain level across the whole generator.
DampBright: each wheel has a damping factor (level robbing/damping/stealing)
BusBright: each drawbar can be equalised globally.
stops: default settings for the eight drawbar gain levels.
The default is 8 linear stages.
wheel: enables redefining the frequency and phase of any given tonewheel
The defaults are the slightly non Even Tempered frequencies of the
Hammond tonewheels. The tonewheel file redefines the top 6 frequencies
that were slightly more out of tune due to the 192-teeth wheels and
a different gear ratio.
crosstalk: between wheels in a compartment and adjacent drawbar busses.
This is one area that may need extensions for crosstalk in the wiring
loom. Currently the level of crosstalk between each of the wheels in
the compartment can be individually defined, and drawbar bus crosstalk
also.
compartment: table of the 24 tonewheel compartments and associated wheels.
resistors: tapering resister definitions for equalisation of gains per
wheel by note by drawbar.
taper: definition of the drawbar taper damping resistor values.Improvements would come with some other alterations to the sine waveforms and some more EQ put into the leslie speaker. The speaker has three speeds, two of which are configurable and the third is 'stopped'. Changes between the different rates is controlled to emulate inertia.
The net emulation, at least of the preacher algorithm, is reasonable, it is distinctively a Hammond sound although it does not have quite as much motor or spindle noise. The Bright button gives a somewhat rawer gearbox. It could do with a better amplifier emulation for overdrive.
The damping algorithms is not quite correct, it has dependencies on which keys are pressed (upper/lower manual). Options drop shadow is taken from the wrong background bitmap so appears in an inconsistent grey.
Vox Continental
---------------This emulates the original mark-1 Continental, popular in its time with the Animals on 'House of the Rising Sun', Doors on 'Light my Fire' and most of their other tracks. Manzarek did use Gibson later, and even played with the Hammond on their final album, 'LA Woman' but this organ in part defined the 60's sound and is still used by retro bands for that fact. The Damned used it in an early revival where Captain Sensible punched the keyboard wearing gloves to quite good effect. After that The Specials began the Mod/Ska revival using one. The sharp and strong harmonic content has the ability to cut into a mix and make its presence known.
The organ was a British design, eventually sold (to Crumar?) and made into a number of plastic alternatives. Compared to the Hammond this was a fully electronic instrument, no moving parts, and much simpler. It had a very characteristic sound though, sharper and perhaps thinner but was far cheaper than its larger cousin. It used a master oscillator that was divided down to each harmonic for each key (as did the later Hammonds for price reasons). This oscillator division design was used in the first of the polyphonic synthesisers where the divided note was fed through individual envelope generators and a shared or individual filter (Polymoog et al).
The Vox is also a drawbar instrument, but far simplified compared to the Hammond. It has 4 harmonic mixes, 16', 8' and 4' drawbars each with eight positions. The fourth gave a mix of 2 2/3, 2, 1 1/3 and 1 foot pipes. An additional two drawbars controlled the overall volume and waveforms, one for the flute or sine waves and another for the reed or ramp waves. The resulting sound could be soft and warm (flute) or sharp and rich (reed).
There are two switches on the modulator panel, one for vibrato effect and one for memories and options. Options give access to an chorus effect rather than the simple vibrato, but this actually detracts from the qualities of the sound which are otherwise very true to the original.
Vox is a trade name owned by Korg Inc. of Japan, and Continental is one of their registered trademarks. Bristol does not intend to infringe upon these registered names and Korg have their own remarkable range of vintage emulations available. You are directed to their website for further information of true Korg products.
Fender Rhodes
-------------Again not an instrument that requires much introduction. This emulation is the DX-7 voiced synth providing a few electric piano effects. The design is a Mark-1 Stage-73 that the author has, and the emulation is reasonable if not exceptional. The Rhodes has always been widely used, Pink Floyd on 'Money', The Doors on 'Riders on the Storm', Carlos Santana on 'She's not There', everybody else in the 60's.
The Rhodes piano generated its sound using a full piano action keyboard where each hammer would hit a 'tine', or metal rod. Next to each rod was a pickup coil as found on a guitar, and these would be linked together into the output. The length of each tine defined its frequency and it was tunable using a tight coiled spring that could be moved along the length of the tine to adjust its moment. The first one was built mostly out of aircraft parts to amuse injured pilots during the second world war. The Rhodes company was eventually sold to Fender and lead to several different versions, the Mark-2 probably being the most widely acclaimed for its slightly warmer sound.
There is not much to explain regarding functionality. The emulator has a volume and bass control, and one switch that reveals the memory buttons and algorithm selector.
The Rhodes would improve with the addition of small amounts of either reverb or chorus, potentially to be implemented in a future release.
The Rhodes Bass was cobbled together largely for a presentation on Bristol. It existed and was used be Manzarek when playing with The Doors in Whiskey-a-GoGo; the owner specified that whilst the music was great they needed somebody playing the bass. Rather than audition for the part Manzarek went out and bought a Rhodes Bass and used it for the next couple of years.
Sequential Circuits Prophet-10
------------------------------The prophet 10 was the troublesome brother of the Pro-5. It is almost two Prophet-5 in one box, two keyboards and a layering capability. Early models were not big sellers, they were temperamental and liable to be temperature sensitive due to the amount of electronics hidden away inside. The original layering and 'unison' allowed the original to function as two independent synths, a pair of layered synths (both keyboards then played the same sound), as a monophonic synth in 'unison' mode on one keyboard with a second polyphonic unit on the other, or even all 10 voices on a single keyed note for a humongous 20 oscillator monophonic monster.
Phil Collins used this synth, and plenty of others who might not admit to it.
The emulator uses the same memories as the Prophet-5, shares the same algorithm, but starts two synths. Each of the two synths can be seen by selecting the U/D (Up/Down) button in the programmer section. Each of the two synthesisers loads one of the Pro-5 memories.
There was an added parameter - the Pan or balance of the selected layer, used to build stereo synths. The lower control panel was extended to select the playing modes:
Dual: Two independent keyboards
Poly: Play note from each layer alternatively
Layer: Play each layer simultaneously.In Poly and Layer mode, each keyboard plays the same sounds.
Mods: Select which of the Mod and Freq wheels control which layers.
Sequential Circuits Prophet-5
Sequential Circuits Prophet-52 (the '5' with chorus)
----------------------------------------------------Sequential circuits released amongst the first truly polyphonic synthesisers where a group of voice circuits (5 in this case) were linked to an onboard computer that gave the same parameters to each voice and drove the notes to each voice from the keyboard. The device had some limited memories to allow for real live stage work. The synth was amazingly flexible regarding the oscillator options and modulation routing, producing some of the fattest sounds around. They also had some of the fattest pricing as well, putting it out of reach of all but the select few, something that maintained its mythical status. David Sylvian of Duran Duran used the synth to wide acclaim in the early 80's as did many of the new wave of bands.
The -52 is the same as the -5 with the addition of a chorus as it was easy, it turns the synth stereo for more width to the sound, and others have done it on the Win platform.
The design of the Prophet synthesisers follows that of the Mini Moog. It has three oscillators one of them as a dedicated LFO. The second audio oscillator can also function as a second LFO, and can cross modulate oscillator A for FM type effects. The audible oscillators have fixed waveforms with pulse width modulation of the square wave. These are then mixed and sent to the filter with two envelopes, for the filter and amplifier.
Modulation bussing is quite rich. There is the wheel modulation which is global, taking the LFO and Noise as a mixed source, and send it under wheel control to any of the oscillator frequency and pulse width, plus the filter cutoff. Poly mods take two sources, the filter envelope and Osc-B output (which are fully polyphonic, or rather, independent per voice), and can route them through to Osc-A frequency and Pulse Width, or through to the filter. To get the filter envelope to actually affect the filter it needs to go through the PolyMod section. Directing the filter envelope to the PW of Osc-A can make wide, breathy scanning effects, and when applied to the frequency can give portamento effects.
LFO:
Frequency: 0.1 to 50 Hz
Shape: Ramp/Triangle/Square. All can be selected, none selected should
give a sine wave (*)
(*) Not yet implemented.Wheel Mod:
Mix: LFO/Noise
Dest: Osc-A Freq/Osc-B Freq/Osc-A PW/Osc-B PW/Filter CutoffPoly Mod: These are affected by key velocity.
Filter Env: Amount of filter envelope applied
Osc-B: Amount of Osc-B applied:
Dest: Osc-A Freq/Osc-A PW/Filter CutoffOsc-A:
Freq: 32' to 1' in octave steps
Shape: Ramp or Square
Pulse Width: only when Square is active.
Sync: synchronise to Osc-BOsc-B:
Freq: 32' to 1' in octave steps
Fine: +/- 7 semitones
Shape: Ramp/Triangle/Square
Pulse Width: only when Square is active.
LFO: Lowers frequency by 'several' octaves.
KBD: enable/disable keyboard tracking.Mixer:
Gain for Osc-A, Osc-B, NoiseFilter:
Cutoff: cuttof frequency
Res: Resonance/Q/Emphasis
Env: amount of PolyMod affecting to cutoff.Envelopes: One each for PolyMod (filter) and amplifier.
Attack
Decay
Sustain
ReleaseGlobal:
Master Volume
A440 - stable sine wave at A440 Hz for tuning.
MIDI: channel up/down
Release: release all notes
Tune: autotune oscillators.
Glide: amount of portamento
Unison: gang all voices to a single 'fat' monophonic synthesiser.This is one of the fatter of the Bristol synths and the design of the mods is impressive (not my design, this is as per sequential circuits spec). Some of the cross modulations are noisy, notably 'Osc-B->Freq Osc-A' for square waves as dest and worse as source.
The chorus used by the Prophet-52 is a stereo 'Dimension-D' type effect. The signal is panned from left to right at one rate, and the phasing and depth at a separate rate to generate subtle chorus through to helicopter flanging.
Memories are loaded by selecting the 'Bank' button and typing in a two digit bank number followed by load. Once the bank has been selected then 8 memories from the bank can be loaded by pressing another memory select and pressing load. The display will show free memories (FRE) or programmed (PRG).
Oberheim OB-X
-------------Oberheim was the biggest competitor of Sequential Circuits, having their OB range neck and neck with each SC Prophet. The sound is as fat, the OB-X similar to the Prophet-5 as the OB-Xa to the Prophet-10. The synths were widely used in rock music in the late seventies and early 80s. Their early polyphonic synthesisers had multiple independent voices linked to the keyboard and were beast to program as each voice was configured independently, something that prevented much live usage. The OB-X configured all of the voices with the same parameters and had non-volatile memories for instant recall.
Priced at $6000 upwards, this beast was also sold in limited quantities and as with its competition gained and maintained a massive reputation for rich, fat sounds. Considering that it only had 21 continuous controllers they were used wisely to build its distinctive and flexible sound.
The general design again follows that of the Mini Moog, three oscillators with one dedicated as an LFO the other two audible. Here there is no mixer though, the two audible oscillators feed directly into the filter and then the amplifier.
The richness of the sound came from the oscillator options and filter, the latter of which is not done justice in the emulator.
Manual:
Volume
Auto: autotune the oscillators
Hold: disable note off events
Reset: fast decay to zero for envelopes, disregards release parameter.
Master Tune: up/down one semitone both oscillators.Control:
Glide: up to 30 seconds
Oscillator 2 detune: Up/down one semitone
Unison: gang all voices to a single 'fat' monophonic synthesiser.Modulation:
LFO: rate of oscillation
Waveform: Sine/Square/Sample&Hold of noise src. Triangle if none selected.
Depth: Amount of LFO going to:
Freq Osc-1
Freq Osc-2
Filter Cutoff
PWM: Amount of LFO going to:
PWM Osc-1
PWM Osc-2Oscillators:
Freq1: 32' to 1' in octave increments.
PulseWidth: Width of pulse wave (*).
Freq2: 16' to 1' in semitone increments.
Saw: sawtooth waveform Osc-1 (**)
Puls: Pulse waveform Osc-1
XMod: Osc-1 FW to Osc-2 (***)
Sync: Osc-2 sync to Osc-1
Saw: sawtooth waveform Osc-2
Puls: Pulse waveform Osc-2
* Although this is a single controller it acts independently on each of the
oscillators - the most recent to have its square wave selected will be
affected by this parameter allowing each oscillator to have a different
pulse width as per the original design.
** If no waveform is selected then a triangle is generated.
*** The original synth had Osc-2 cross-modifying Osc-1, this is not totally
feasible with the sync options as they are not mutually exclusive here.
Cross modulation is noisy if the source or dest wave is pulse, something
that may be fixed in a future release.Filter:
Freq: cutoff frequency
Resonance: emphasis (*)
Mod: Amount of modulation to filter cutoff (**)
Osc-1: Osc-1 to cutoff at full swing.
KDB: Keyboard tracking of cutoff.
Half/Full: Oscillator 2 to Cutoff at defined levels (***)
Half/Full: Noise to Cutoff at defined levels (***)
* In contrast to the original, this filter can self oscillate.
** The original had this parameter for the envelope level only, not the
other modifiers. Due to the filter implementation here it affects total
depth of the sum of the mods.
*** These are not mutually exclusive. The 'Half' button gives about 1/4,
the 'Full' button full, and both on gives 1/2. They could be made mutually
exclusive, but the same effect can be generated with a little more flexibility
here.Envelopes: One each for filter and amplifier.
Attack
Decay
Sustain
ReleaseThe oscillators appear rather restricted at first sight, but the parametrics allow for a very rich and cutting sound.
Improvements would be a fatter filter, but this can be argued of all the Bristol synthesisers as they all share the same design. It will be altered in a future release.
The OB-X has its own mod panel (most of the rest share the same frequency and mod controls). Narrow affects the depth of the two controllers, Osc-2 will make frequency only affect Osc-2 rather than both leading to beating, or phasing effects if the oscillators are in sync. Transpose will raise the keyboard by one octave.
Memories are quite simple, the first group of 8 buttons is a bank, the second is for 8 memories in that bank. This is rather restricted for a digital synth but is reasonably true to the original. If you want more than 64 memories let me know.
Oberheim OB-Xa
--------------This is almost two OB-X in a single unit. With one keyboard they could provide the same sounds but with added voicing for split/layers/poly options. The OB-Xa did at least work with all 10 voices, had a single keyboard, and is renown for the sounds of van Halen 'Jump' and Stranglers 'Strange Little Girl'. The sound had the capability to cut through a mix to upstage even guitar solo's. Oberheim went on to make the most over the top analogue synths before the cut price alternatives and the age of the DX overcame them.
Parameters are much the same as the OB-X as the algorithm shares the same code, with a few changes to the mod routing. The main changes will be in the use of Poly/Split/Layer controllers for splitting the keyboard and layering the sounds of the two integrated synthesisers and the choice of filter algorithm.
The voice controls apply to the layer being viewed, selected from the D/U button.
Manual:
Volume
Balance
Auto: autotune the oscillators
Hold: disable note off
Reset: fast decay to zero for envelopes, disregards release parameter.
Master Tune: up/down one semitone both oscillators.Control:
Glide: up to 30 seconds
Oscillator 2 detune: Up/down one semitone
Unison: gang all voices to a single 'fat' monophonic synthesiser.Modulation:
LFO: rate of oscillation
Waveform: Sine/Square/Sample&Hold of noise src. Triangle if none selected.
Depth: Amount of LFO going to:
Freq Osc-1
Freq Osc-2
Filter Cutoff
PWM: Amount of LFO going to:
PWM Osc-1
PWM Osc-2
TremoloOscillators:
Freq1: 32' to 1' in octave increments.
PulseWidth: Width of pulse wave (*).
Freq2: 16' to 1' in semitone increments.
Saw: sawtooth waveform Osc-1 (**)
Puls: Pulse waveform Osc-1
Env: Application of Filter env to frequency
Sync: Osc-2 sync to Osc-1
Saw: sawtooth waveform Osc-2
Puls: Pulse waveform Osc-2
* Although this is a single controller it acts independently on each of the
oscillators - the most recent to have its square wave selected will be
affected by this parameter allowing each oscillator to have a different
pulse width, as per the original design.
** If no waveform is selected then a triangle is generated.Filter:
Freq: cutoff frequency
Resonance: emphasis (*)
Mod: Amount of modulation to filter cutoff (**)
Osc-1: Osc-1 to cutoff at full swing.
KDB: Keyboard tracking of cutoff.
Half/Full: Oscillator 2 to Cutoff at defined levels (***)
Noise: to Cutoff at defined levels
4 Pole: Select 2 pole or 4 pole filter
* In contrast to the original, this filter will self oscillate.
** The original had this parameter for the envelope level only, not the
other modifiers. Due to the filter implementation here it affects total
depth of the sum of the mods.
*** These are not mutually exclusive. The 'Half' button gives about 1/4,
the 'Full' button full, and both on gives 1/2. They could be made mutually
exclusive, but the same effect can be generated with a little more flexibility
here.Envelopes: One each for filter and amplifier.
Attack
Decay
Sustain
ReleaseMode selection:
Poly: play one key from each layer alternatively for 10 voices
Split: Split the keyboard. The next keypress specifies split point
Layer: Layer each voice on top each other.
D/U: Select upper and lower layers for editing.Modifier Panel:
Rate: Second LFO frequency or Arpeggiator rate (*)
Depth: Second LFO gain
Low: Modifiers will affect the lower layer
Up: Modifiers will affect the upper layer
Multi: Each voice will implement its own LFO
Copy: Copy lower layer to upper layer
Mod 01: Modify Osc-1 in given layer
Mod 02: Modify Osc-2 in given layer
PW: Modify Pulse Width
AMT: Amount (ie, depth) of mods and freq wheels
Transpose: Up or Down one octave.The Arpeggiator code integrated into release 0.20.4 has three main parts, the arpeggiator itself, the arpeggiating sequencer and the chording. All are configured from the left of the main panel.
The arpeggiator is governed by the rate control that governs how the code steps through the available keys, an octave selector for 1, 2 or 3 octaves of arpeggiation, and finally the Up/Down/Up+Down keys - the last ones start the arpeggiator. Arpeggiation will only affect the lower layer.
When it has been started you press keys on the keyboard (master controller or GUI) and the code will step through each note and octaves of each note in the order they were pressed and according to the direction buttons. The key settings are currently reset when you change the direction and you will have to press the notes again.
The sequencer is a modification of the code. Select the Seq button and then a direction. The GUI will program the engine with a series of notes (that can be redefined) and the GUI will sequence them, also only into the lower layer. The sequence will only start when you press a key on the keyboard, this is the starting point for the sequence. You can press multiple notes to have them sequence in unison. Once started you can tweak parameters to control the sound and memory 88 when loaded has the filter envelope closed down, a bit of glide and some heavy mods to give you a starting point for some serious fun.
To reprogram the sequence steps you should stop the sequencer, press the PRG button, then the Sequence button: enter the notes you want to use one by one on the keyboard. When finished press the sequence button again, it goes out. Now enable it again - select Seq and a direction and press a note. Press two notes.
When you save the memory the OBXa will also save the sequence however there is only one sequence memory - that can be changed if you want to have a sequence memory per voice memory (implemented in 0.20.4).
The chord memory is similar to the Unison mode except that Unison plays all voices with the same note. Chording will assign one voice to each notes in the chord for a richer sound. To enable Chording press the 'Hold' button. This is not the same as the original since it used the hold button as a sustain option however that does not function well with a GUI and so it was reused.
To reprogram the Chord memory do the following: press the PRG button then the Hold button. You can then press the keys, up to 8, that you want in the chord, and finally hit the Hold button again. The default chord is just two notes, the one you press plus its octave higher. This results in multiple voices per keypress (a total of 3 in Layered mode) and with suitable detune will give a very rich sound.
There is only one arpeggiator saved for all the memories, not one per memory as with some of the other implementations. Mail me if you want that changed.
The oscillators appear rather restricted at first sight, but the parametrics allow for a very rich and cutting sound.
The Copy function on the Mod Panel is to make Poly programming easier - generate the desired sound and then copy the complete parameter set for poly operation. It can also be used more subtly, as the copy operation does not affect balance or detune, so sounds can be copied and immediately panned slightly out of tune to generate natural width in a patch. This is not per the original instrument that had an arpeggiator on the mod panel.
The Arpeggiator was first integrated into the OBXa in release 0.20.4 but not widely tested.
KORG MONOPOLY
-------------A synth suite would not be complete without some example of a Korg instrument, the company was also pivotal in the early synthesiser developments. This is an implementation of their early attempts at polyphonic synthesis, it was either this one or the Poly-6 (which may be implemented later). Other choices would have been the MS series, MS-20, but there are other synth packages that do a better job of emulating the patching flexibility of that synth - Bristol is more for fixed configurations.
As with many of the Korg synths (the 800 worked similarly) this is not really true polyphony, and it is the quirks that make it interesting. The synth had four audio oscillators, each independently configurable but which are bussed into a common filter and envelope pair - these are not per voice but rather per instrument. The unit had different operating modes such that the four oscillators can be driven together for a phat synth, independently for a form of polyphony where each is allocated to a different keypress, and a shared mode where they are assigned in groups depending on the number of keys pressed. For example, if only 2 notes are held then each key is sounded on two different oscillators, one key is sounded on all 4 oscillators, and 3 or more have one each. In addition there are two LFOs for modulation and a basic effects option for beefing up the sounds. To be honest to the original synth, this emulation will only request 1 voice from the engine. Korg is one of the few original manufacturers to have survived the transition to digital synthesis and are still popular.
One thing that is immediately visible with this synth is that there are a lot of controllers since each oscillator is configured independently. This is in contrast to the true polyphonic synths where one set of controls are given to configure all the oscillators/filters/envelopes. The synth stages do follow the typical synth design, there are modulation controllers and an FX section feeding into the oscillators and filter. The effects section is a set of controllers that can be configured and then enabled/disabled with a button press. The overall layout is rather kludgey, with some controllers that are typically grouped being dispersed over the control panel.
Control:
Volume
Arpeg:
Whether arpeggiator steps up, down, or down then up. This works in
conjunction with the 'Hold' mode described later.
Glide: glissando note to note. Does not operate in all modes
Octave: Up/Normal/Down one octave transpose of keyboard
Tune: Global tuning of all oscillators +/- 50 cents (*)
Detune: Overall detuning of all oscillators +/- 50 cents (*)
* There is an abundance of 'Tune' controllers. Global Tuning affects all
the oscillators together, then oscillators 2, 3 and 4 have an independent
tune controller, and finally there is 'Detune'. The target was to tune all
the oscillators to Osc-1 using the independent Tune for each, and then use
the global Tune here to have the synth tuned to other instruments. The
Detune control can then be applied to introduce some beating between the
oscillators to fatten the sound without necessarily losing overall tune of
the instrument.Modulation wheels:
Bend:
Intensity: Depth of modulation
Destination:
VCF - Filter cutoff
Pitch - Frequency of all oscillators
VCO - Frequency of selected oscillators (FX selection below).
MG1: Mod Group 1 (LFO)
Intensity: Depth of modulation
Destination:
VCF - Filter cutoff
Pitch - Frequency of all oscillators
VCO - Frequency of selected oscillators (FX selection below).LFO:
MG-1:
Frequency
Waveform - Tri, +ve ramp, -ve ramp, square.
MG-2:
Frequency (Triangle wave only).Pulse Width Control:
Pulse Width Modulation:
Source - Env/MG-1/MG-2
Depth
Pule Width
Width control
These controllers affect Osc-1 though 4 with they are selected for either
square of pulse waveforms.Mode:
The Mono/Poly had 3 operating modes, plus a 'Hold' option that affects
each mode:
Mono: All oscillators sound same key in unison
Poly: Each oscillator is assigned independent key - 4 note poly.
Share: Dynamic assignment:
1 key - 4 oscillators = Mono mode
2 key - 2 oscillators per key
3/4 - 1 oscillator per key = Poly mode
The Hold function operates in 3 different modes:
Mono: First 4 keypresses are memorised, further notes are then chorded
together monophonically.
Poly:
Notes are arpeggiated in sequence, new note presses are appended
to the chain. Arpeggiation is up, down or up/down.
Share:
First 4 notes are memorised and are then arpeggiated in sequence,
new note presses will transpose the arpeggiation. Stepping is up,
down or up/down.
There are several controllers that affect arpeggiation:
Arpeg - direction of stepping
MG-2 - Frequency of steps from about 10 seconds down to 50 bps.
Trigger - Multiple will trigger envelopes on each step.Effects:
There are three main effects, or perhaps rather modulations, that are
controlled in this section. These are vibrato, cross-modulated frequency
and oscillator synchronisation. The application of each mod is configured
with the controllers and then all of them can be enabled/disabled with
the 'Effects' button. This allows for big differences in sound to be
applied quickly and simply as a typical effect would be. Since these mods
apply between oscillators it was envisaged they would be applied in Mono
mode to further fatten the sound, and the Mono mode is actually enabled when
the Effects key is selected (as per the original instrument). The Mode can
be changed afterwards for Effects/Poly for example, and they work with the
arpeggiation function.
X-Mod: frequency cross-modulation between oscillators
Freq: frequency modulation by MG-1 (vibrato) or Envelope (sweep)
Mode:
Syn: Oscillators are synchronised
X-M: Oscillators are cross-modulated
S-X: Oscillators are cross-modulated and synchronised
SNG:
Single mode: synth had a master oscillator (1) and three slaves (2/3/4)
DBL:
Double mode: synth had two master (1/3) and two slaves (2/4)
The overall FX routing depends on the SNG/DBL mode and the selection of
Effects enabled or not according to the table below. This table affects
the FX routing and the modulation wheels discussed in the LFO section above:
--------------------------------------------------
| FX OFF | FX ON |
| |----------------------------------
| | Single | Double |
---------------+--------------+-----------------+---------------|
| VCO-1/Slave | VCO-1 | VCO 2/3/4 | VCO 2/4 |
| | | | |
| Pitch | VCO 1-4 | VCO 1-4 | VCO 1-4 |
| | | | |
| VCF | VCF | VCF | VCF |
-----------------------------------------------------------------
So, glad that is clear. Application of the modulation wheels to Pitch and
VCF is invariable when they are selected. In contrast, VCO/Slave will have
different destinations depending on the Effects, ie, when effects are on
the modwheels will affect different 'slave' oscillators.Oscillators:
Each oscillator had the following controllers:
Tune (*)
Waveform: Triangle, ramp, pulse, square (**)
Octave: Transpose 16' to 2'
Level: output gain/mix of oscillators.
* Osc-1 tuning is global
** width of pulse and square wave is governed by PW controller. The
modulation of the pulse waveform is then also controlled by PWM.Noise:
Level: white noise output gain, mixed with oscillators into filter.VCF:
Freq:
Cutoff frequency
Res:
Resonance/emphasis.
Env:
Amount of contour applied to cutoff
KBD:
Amount of key tracking applied.ADSR: Two: filter/PWM/FX, amplifier
Attack
Decay
Sustain
Release
Trigger:
Single: Trigger once until last key release
Multi: Trigger for each key or arpeggiator step.
Damp:
Off: Notes are held in Poly/Share mode until last key is released.
On: Oscillators are released as keys are released.This is more a synth to play with than describe. It never managed to be a true blue synth perhaps largely due to its unusual design: the quasi-poly mode was never widely accepted, and the effects routing is very strange. This does make it a synth to be tweaked though.
Some of the mod routings do not conform to the original specification for the different Slave modes. This is the first and probably the only bristol synth that will have an inbuilt arpeggiator. The feature was possible here due to the mono synth specification, and whilst it could be built into the MIDI library for general use it is left up to the MIDI sequencers (that largely came along to replace the 1980s arpeggiators anyway) that are generally available on Linux. [Other instruments emulated by bristol that also included arpeggiation but do not have in the emulation were the Juno-6, Prophet-10, Oberheim OB-Xa, Poly6].
As of May 06 this synth was in its final stages of development. There are a few issues with Tune and Detune that need to be fixed, and some of the poly key assignment may be wrong.
KORG POLY 6
-----------Korg in no way endorses this emulation of their classic synthesiser and have their own emulation product that gives the features offered here. Korg, Mono/Poly, Poly-6, MS-20, Vox and Continental are all registered names or trademarks of Korg Inc. of Japan.
Quite a few liberties were taken with this synth. There were extremely few
differences between the original and the Roland Juno 6, they both had one osc
with PWM and a suboscillator, one filter and envelope, a chorus effect, and
inevitably both competed for the same market space for their given price. To
differentiate this algorithm some alterations were made. There are two separate
envelopes rather than just one, but the option to have a gated amplifier is
still there. In addition glide and noise were added, both of which were not in
the original instrument. With respect to the original instrument this was
perhaps not a wise move, but there seemed little point in making another Juno
with a different layout. The net results is that the two synths do sound quite
different. The emulation does not have an arpeggiator.
Volume: Master volume of the instrument
Glide: length of portamento
Tune: Master tuning of instrument
Bend: Amount of pitch wheel that is applied to the oscillators frequency.
VCO section:
Octave: What octave the instrument's keyboard is in.
Wave: Waveform selection: Triangle, Saw, Pulse and Pulsewidth
PW PWM: Amount of Pulsewidth (when Pulse is selected) and Pulsewidth
Modulation (When Pulsewidth is selected).
Freq: Frequency of PW/PWM
OFF/SUB1/SUB2; Adds a square sub-oscillator either off, 1 or 2 octaves
down from a note.
MG (Modulation Group):
Freq: Frequency of LFO
Delay: Amount of time before the LFO affects the destination when a key
is pressed.
Level: How strongly the LFO affects the destination
VCO/VCF/VCA: Destinations that the LFO can go to:
VCO: The Voltage Controlled Oscillator:
Affects oscillator pitch, producing vibrato
VCF: The Voltage Controlled Filter:
Affects Filter, producing a wah effect
VCA: The Voltage Controlled Amplifier:
Affects the Amplifier, producing tremolo
VCF section:
Freq: Cut off frequency of the filter
Res: Resonance of the filter
Env: By how much the filter is affected by the envelope.
Kbd: How much Keyboard tracking is applied to the envelope. note:
A low setting doesn't allow the filter to open, making the notes
seem darker the further you go up the keyboard.
Hold: prevent key off events
Mono Mode: Gang all voices to a single 'fat' monophonic synthesiser.
Poly: One voice per note.
Envelope Section:
Top:
Filter envelope:
Attack: Amount of time it takes the filter to fully open.
A high value can produce a 'sweeping filter' effect.
Decay: Amount of time it takes for the filter to close to
the sustain level
Sustain: Amount of filter that is sustained when a key is held
Release: Amount of time it takes for the filter envelope to stop
affecting the filter. Combining a low filter release with a
high amplitude release time can cause an interesting effect.
Bottom:
Amplitude envelope:
Attack: Amount of time it takes for the signal to reach its peak.
Decay: Amount of time it takes for the signal to drop to the
sustain level
Sustain: How quickly the sound decays to silence.
Release: How long it takes the sound to decay to silence after
releasing a key.
VCA:
Env: When on, this causes the Amplitude envelope to affect the sound.
i.e., If you have a long attack time, you get a long attack time.
Gate: When on, this causes the Amplitude envelope only (not the filter
envelope) to be be bypassed.
Gain: Gain of signal.
Effects Section:
0: No effects
1: Soft Chorus
2: Phaser
3: Ensemble
Intensity: How much the effects affect the output. There are some mildly anomalous effects possible from the MG section, especially with the VCA. The MG and the env are summed into the VCA which means if the env decays to zero then the LFO may end up pumping the volume, something that may be unexpected. Similarly, if the LFO is pumping and the voice finally stops its cycle then the closing gate may cause a pop on the MG signal. These can be resolved however the current behaviour is probably close to the original.
Bristol thanks Andrew Coughlan for patches, bug reports, this manual page and diverse suggestions to help improve the application.
Korg in no way endorses this emulation of their classic synthesiser and have
their own emulation product that gives the features offered here. Korg,
Mono/Poly, Poly-6, MS-20, Vox and Continental are all registered names or
trademarks of Korg Inc. of Japan.
ARP AXXE
--------TBD
At the risk of getting flamed, this is potentially the ugliest synth ever made, although the competition is strong. It was implemented as a build up to the far more useful ARP 2600 to understand the ARP components and their implementation.
The implementation is a giveaway written during a week long business trip to Athens to keep me busy in the hotel. Its design lead on to the Odyssey and that was the step towards the final big brother, the ARP 2600.
ARP ODYSSEY
-----------Ring modulation is correct here, it is a multiplier. This deviates from the original instrument that used an XOR function on the pulsewave outputs of the two oscillators. The implementation has two models, Mark-I and Mark-II. These implement different filters as per the original. Although their characteristics are different it is not suggested they are a particularly close emulation of the original.
TBD
Memory Moog
-----------TBD.
This is actually a lot warmer than the Mini emulator, largely due to being later code. The mini should be revisited but I am saving that pleasure for when some more filters are available. [This was done during the 0.20 stream using the Huovilainen filters and bandwidth limited oscillators to produce a far richer sound. Also incorporate a number of fixes to the emulation stages.].
ARP 2600
--------This synth will probably never get a writeup, it is kind of beyond the scope of this document. There are some discrepancies with the original:
The filters do not self oscillate, they require an input signal. The output stage is global to all voices so cannot be patched back into the signal path. The original did not have a chorus, only a spring reverb. The input stage has not been tested for either signal nor envelope following code. The voltage manipulators were not in the first bristol upload with this emulation (-60), but a future release will include mixing inverters, a lag processor, and possibly also a Hz->V extractor. The unit has an extra LFO where the original had just a clock trigger circuit, it produces a TRI wave, can be used to trigger the AR envelope and be used for modulation. The electroswitch is unidirectional, two inputs switchable to one output. The sample and hold circuit cannot accept an external clock. The Keyboard inputs to the VCO cannot accept and alternative signal other than the MIDI note with tracking of this note either enabled or disabled.
The rest works, ie, all the VCO/VCF/VCA/ENV/AMP and any of the 30 or so outputs can be repatched into any of the 50 or so inputs. Patches cause no overhead in the engine as it uses default buffering when not repatched, so feel free to put in as many cables as you can fit. Patches in the GUI still demand a lot of CPU cycles. Release -77 improved this about 5-fold and further improvements are in the pipeline: the 0.10 stream implemented colour caching and XImage graphics interface which massively improved GUI performance.
REALISTIC MG-1 CONCERTMATE
--------------------------This is a pimpy little synth. It was sold through the Realistic electronics chain, also known as Radio Shack (and as Tandy, in the UK at least). It was relatively cheap but had a design from Moog Music (from after Robert Moog had left?) including the patented ladder filter. It consisted of a monophonic synth, dual oscillator, lfo, noise, filter, env, and a ring modulator. On top of that there was an organ circuit to give 'polyphony'. It was not really polyphonic although different descriptions will tell you it had 10 voices. These write-ups are by people who probably only had 10 fingers, the truth is that the organ circuit was as per any other - it had a master oscillator at about 2MHz and this was divided using binary counters to deliver a frequency for every note. The output of the 'poly' section was lamentable at best, it is a fairly pure square wave passed through the filter and contour. This is fully emulated although in addition to the contour bristol implements a per note envelope just to groom the note - this prevents ticks when new keys are pressed with the mono envelope fully open. There is no access to this env, it just has fast attack and decay times to smooth the signal and is preconfigured by the user interface on startup.
The mono section is reasonably fun, the oscillators can be synchronised and there is a ring modulator so the range of sounds is quite wide. The emulator uses a chaimberlain filter so is not as warm as the Moog ladder filters.
The list of people who used this is really quite amazing. The promotion for the product had Elton John holding one up in the air, although seeing as he probably already had every other synth known to man, holding it up in the air is likely to be all he ever did with it. Who knows how much they had to pay him to do it - the photo was nice though, from the days when Elton was still bald and wearing ridiculously oversized specs.
Tuning:
One control each for the poly oscillator and mono oscillatorsGlide:
Only affects the monophonic oscillators.Modulation:
One LFO with rate and waveshape selection
produces tri, square and S/H signals.
can trigger the envelope
One noise source.
The modulation can be directed to:
Oscillators for vibrato
Filter for wah-wah effectsOscillator-1:
Tri or square wave
Octave from -2 to 0 transposition
Sync selector (synchronises Osc-2 to Osc-1)Oscillator-2:
Tri or pulse wave
Detune. This interoperates with the sync setting to alter harmonics
Octave from -1 to +1 transpositionContour: This is not an ADSR, rather an AR envelope
Sustain: AR or ASR envelope selector.
Tracking: controls mono oscillators
Envelope control
Key tracking (gate, no env)
Continuous (always on)
Rise (attack time)
Fall (release time)Filter:
Cutoff frequency
Emphasis
Contour depth
Keyboard tracking off, 1/2, full.Mixer: Levels for Mono Osc-1 Mono Osc-2 Noise RingMod of the mono oscillators (called 'bell'). Poly Osc level.
Master Volume control.
One extra button was added to save the current settings. For the rest the controls reflect the simplicity of the original. The implementation is a single synth, however due to the engine architecture having a pre-operational routine, a post-operational routine and an operate(polyphonic emulator) the emulation executes the mono synth in the pre- and post- ops to be mono, these are called just once per cycle. The poly synth is executed in the operate() code so is polyphonic. This leads to one minor deviation from the original routing in that if you select continuous tone controls then you will also hear one note from the poly section. This is a minor issue as the poly oscillator can be zeroed out in the mixer.
It is noted here that this emulation is just a freebie, the interface is kept simple with no MIDI channel selection (start it with the -channel option and it stays there) and no real memories (start it with the -load option and it will stay on that memory location). There is an extra button on the front panel (a mod?) and pressing it will save the current settings for next time it is started. I could have done more, and will if people are interested, but I built it since the current developments were a granular synth and it was hard work getting my head around the grain/wave manipulations, so to give myself a rest I put this together one weekend. The Rhodesbass and ARP Axxe were done for similar reasons. I considered adding another mod button, to make the mono section also truly polyphonic but that kind of detracts from the original. Perhaps I should put together a Polymoog sometime that did kind of work like that anyway.
This was perhaps a strange choice, however I like the way it highlights the difference between monophonic, polyphonic and 'neopolyphonic' synthesised organs (such as the Polymoog). Its a fun synth as well, few people are likely to every bother buying one as they cost more now than when they were produced due to being collectable: for the few hundred dollars they would set you back on eBay you can get a respectable polyphonic unit. So here is an emulator, for free, for those who want to see how they worked.
Vox Continental 300
-------------------There is an additional emulator for the later Mark-II, Super, 300 or whatever model you want to call it. This is probably closest to the 300. It was a dual manual organ, the lower manual is a Continental and the upper manual had a different drawbar configuration, using 8', 4' and 2', another two compound drawbars that represented 5-1/3'+1-3/5', and 2-2/3'+2'+1' respectively. This gave upper manual a wider tonic range, plus it had the ability to apply some percussive controls to two of the drawbars. Now, depending on model, some of these values could be different and bristol does not emulate all the different combinations, it uses the harmonics described above and applies percussive to the 2' and 5-1/3' harmonics (which is arguably incorrect however it gives a wider combination of percussive harmonics).
The percussive has 4 controls, these are selectors for the harmonics that will be driven through the percussive decay (and then no longer respond to the drawbars), a decay rate called 'L' which acts as a Longer decay when selected, and a volume selector called 'S' which stands for Soft. The variables are adjustable in the mods section. The mods panel is intended to be hidden as they are just variable parameters. On the original units these were PCB mounted pots that were not generally accessible either. The panel is visible when you turn the power control off, not that I suppress the keyboard or anything when the power is off, but it gave me something useful do to with this button. The transparency layer is fixed here and is used to apply some drop shadow and a few beer spills on the cover.
There is an additional Bass section for those who bought the optional Bass pedals (my old one had them). The emulation allow the selection of Flute and Reed strengths, and to select 8' or 8'/16' harmonics. The 'Sustain' control does not currently operate (0.10.9) but that can be fixed if people request the feature.
The lower manual responds to the MIDI channel on which the emulation was started. The upper manual responds to notes greater than MIDI key 48 on the next channel up. The Bass section also responds to this second channel on keys lower than #48. Once started you cannot change the MIDI channel - use the '-channel' option at startup to select the one you want. The actual available max is 15 and that is enforced.
The emulation only contains 6 available presets and a 'Save' button that you need to double click to overwrite any preset. The emulation actually uses banks, so if you started it with '-load 23' it would start up by selecting bank 20, and load memory #3 from that bank. Any saved memories are also then written back to bank 20, still with just 6 memories accessible 20-25. You can access more via MIDI bank select and program change operations if suitably linked up.
Vox is a trade name owned by Korg Inc. of Japan, and Continental is one of their registered trademarks. Bristol does not intend to infringe upon these registered names and Korg have their own remarkable range of vintage emulations available. You are directed to their website for further information of true Korg products.
Roland Jupiter 8
----------------This emulator is anticipated in 0.20.4.
The Jupiter synthesizers were the bigger brothers of the Juno series: their capabilities, sounds and prices were all considerably larger. This is the larger of the series, the others being the -4 and -6. The -6 and the rack mounted MKS-80 both came out after the Jupiter-8 and had somewhat more flexible features. Several of these have been incorporated into the emulation and that is documented below.
A quick rundown of the synth and emulation:
The synth runs as two layers, each of which is an independent emulator running the same algorithm, both layers are controlled from the single GUI. The layers are started with a set of voices, effectively 4+4 per default however bristol plays with those numbers to give the split/layer at 4 voices each and the 'All' configuration with 8 voices - it juggles them around depending on the Poly mode you select. You can request a different number of voices and the emulator will effectively allocate half the number to each layer. If you request 32 voices you will end up with 4+4 though since 32 is interpreted as the default.
The Poly section is used to select between Dual layers, Split keyboard and the 8voice 'All' mode. You can redefine the split point with a double click on the 'Split' button and then pressing a key. If you have linked the GUI up to the MIDI you should be able to press a key on your master keyboard rather than on the GUI.
After that you can select the layer as upper or lower to review the parameter settings of each layer: they are as follows:
LFO: Frequency Delay Waveform (tri, saw, square, s&h)
VCO Mods: LFO and ENV-1 Destination to modulate frequency of DCO1, DCO2 or both.
PWM: PW PWM Modified by Env-1 or LFO
DCO-1: Cross-mod (FM) from DCO2 to DCO1 Modified by Env-1
Octave range 16' to 2' (all mixable)
Waveform: Tri, saw, pulse, square (all mixable)DCO-2: Sync (1->2 or 2->1 or off) Range: 32' to 2' (all mixable) Tuning Waveform: tri, saw, pulse, noise (all mixable)
Mix: Osc 1 and Osc 2
HPF: High pass filter of signal
Filter: Cutoff Emphasis LPF/BPF/HPF Env modulation Source from Env-1 or Env-2 LFO mod amount Keyboard tracking amount
VCA: Env-2 modulation LFO modulation
ADSR-1: A/D/S/R Keyboard tracking amount Invert
ADSR-2: A/D/S/R Keyboard tracking amount
Pan: Stereo panning of layer
All of the above 40 or so parameters are part of the layer emulation and are separately configurable.
The keyboard can operate in several different modes which are selectable from the Poly and Keyboard mode sections. The first main one is Dual, Split and All. Dual configure the two synth layers to be placed on top of each other. Split configures them to be next to each other and by double clicking the split button you can then enter a new split point by pressing a key. The All setting gives you a single layer with all 8 voices active. These settings are for the whole synth.
The Poly section provides different playing modes for each layer independently. There are 3 settings: Solo give the layer access to a single voice for playing lead solos. Unison give the layer however many voices it is allowed (8 if in the All mode, 4 otherwise) and stacks them all on top of each other. This is similar to Solo but with multiple voices layered onto each other. Unison is good for fat lead sounds, Solo better for mono bass lines where Unison might have produced unwanted low frequency signal phasing. The third option is Poly mode 1 where the synth allocates a single voice to each key you press. The original also had Poly mode 2 which was not available at the first bristol release - this mode would apply as many notes as available to the keys you pressed: 1 key = 8 voices as in Unison, with 2 keys pressed each would get 4 voices each, 4 keys pressed would get 2 voices and mixtures in there for other key combinations. This may be implemented in a future release but it is a rather left field option and would have to be put into the MIDI library that controls the voice assignments.
The arpeggiator integrated into bristol is a general design and will differ from the original. The default settings are 4 buttons controlling the range of the arpeggiation, from 1 to 4 octaves, 4 buttons controlling the mode as Up, Down, Up+Down or Random sequencing of the notes available, and 4 notes that are preloaded into the sequence.
Finally there are two global controls that are outside of the memories - the rate and clock source (however externally driven MTC has not been implemented yet). It is noted that the Arpeggiator settings are separate from the sequence information, ie, Up/Down/Rnd, the range and the arpeggiator clock are not the same as the note memory, this is discussed further in the memory setting section below.
It is possible to redefine the arpeggiator sequence: select the function button on the right hand side, then select any of the arpeggiator mode buttons, this will initiate the recording. It does not matter which of the mode is selected since they will all start the recording sequence. When you have finished then select the mode button again (you may want to clear the function key if still active). You can record up to 256 steps, either from the GUI keyboard or from a master controller and the notes are saved into a MIDI key memory.
There is no capability to edit the sequences once they have been entered, that level of control is left up to separate MIDI sequencers for which there are many available on Linux. Also, the note memory is actually volatile and will be lost when the emulation exits. If you want to save the settings then you have to enter them from the GUI keyboard or make sure that the GUI is linked up to the master keyboard MIDI interface - you need to be able to see the GUI keyboard following the notes pressed on the master keyboard since only when the GUI sees the notes can it store them for later recall. If the GUI did view the sequence entered here then it will be saved with the patch in a separate file (so that it can be used with other bristol synths).
In addition to the Arpeggiator there is the 'Chord' control. The original synth had two green panel buttons labelled 'Hold', they were actually similar to the sustain pedal on a MIDI keyboard or piano, with one for each layer of the synth. They have been redefined here as Chord memory. When activated the layer will play a chord of notes for every key press. The notes are taken from separate chord memory in the Arpeggiator sequencer. The result is very similar to the Unison mode where every voice is activated for a single key, the difference here is that every voice may be playing a different note to give phat chords. To configure a chord you enable the function key and the target Hold button to put the synth into chord learning mode, play a set of notes (you don't have to hold them down), and click again to finalise the chord. If there are more chord notes than voices available then all voices will activate. If there are more voices than notes then you will be able to play these chord polyphonically, for example, if you have 8 voices and entered just 4 chorded notes then you will have 2 note polyphony left. You should also be able to play arpeggiations of chords. The maximum number of notes in a chord is 8.
The synth has a modifier panel which functions as performance options which can be applied selectively to different layers:
Bender:
This is the depth of the settings and is mapped by the engine to
continuous controller 1 - the 'Mod' wheel. The emulation also tracks
the pitch wheel separately.
Bend to VCO
This applies an amount of pitch bend from the Mod wheel selectively
to either VCO-1 and/or VCO-2. These settings only affect the Mod
layers selected from the main panel. Subtle modifications applied in
different amounts to each oscillator can widen the sound considerable
by introducing small amounts of oscillator phasing.
Bend to VCF
Affects the depth of cutoff to the filter with on/off available. Again
only applies to layers activate with the Mod setting.
LFO to VCO:
The mod panel has a second global LFO producing a sine wave. This can
be driven in selectable amounts to both VCO simultaneously. Layers are
selected from the Mod buttons.
LFO to VCF:
The LFO can be driven in selectable amounts to both VCO or to the VCF.
Layers are selected from the Mod buttons.
Delay:
This is the rise time of the LFO from the first note pressed. There is
no apparent frequency control of the second LFO however bristol allows
the frequency and gain of the LFO to track velocity using function B4
(see below for function settings). Since there is only one LFO per
emulation then the velocity tracking can be misleading as it only
tracks from a single voice and may not track the last note. For this
reason it can be disabled. Using a tracking from something like channel
pressure is for future study.
Glide:
Glissando between key frequencies, selectable to be either just to the
upper layer, off, or to both layers.
Transpose:
There are two transpose switches for the lower and upper layers
respectively. The range is +/1 one octave.Modifier panel settings are saved in the synth memories and are loaded with the first memory (ie, with dual loaded memories discussed below). The ability to save these settings in memory is an MKS-80 feature that was not available in either the Jupiter-6 or -8.
There are several parts to the synth memories. Layer parameters govern sound generation, synth parameters that govern operating modes such Dual/Split, Solo/Unison etc., Function settings that modify internal operations, the parameters for the mod panel and finally the Arpeggiator sequences. These sequences are actually separate from the arpeggiator settings however that was covered in the notes above.
When a patch is loaded then only the layer parameters are activated so that the new sound can be played, and the settings are only for the selected layer. This means any chord or arpeggiation can be tried with the new voice active.
When a memory is 'dual loaded' by a double click on the Load button then all the memory settings will be read and activated: the current layer settings, synth settings, operational parameters including the peer layer parameters for dual/split configurations. Dual loading of the second layer will only happen if the memory was saved as a split/double with a peer layer active.
The emulation adds several recognised Jupiter-6 capabilities that were not a part of the Jupiter-8 product. These are
1. PW setting as well as PWM
2. Cross modulation can be amplified with envelope-1 for FM type sounds
3. Sync can be set in either direction (DCO1 to 2 or DCO2 to 1)
4. The waveforms for DCO 1&2 are not exclusive but mixable
5. The LFO to VCA is a continuous controller rather than stepped
6. The envelope keyboard tracking is continuous rather than on/off
7. The filter option is multimode LP/BP/HP rather than 12/24dB
8. Layer detune is configurable
9. Layer transpose switches are available
10. Arpeggiator is configurable on both layersBeyond these recognised mods it is also possible to select any/all DCO transpositions which further fattens up the sound as it allows for more harmonics. There is some added detune between the waveforms with its depth being a function of the -detune setting. Separate Pan and Balance controls have been implemented, Pan is the stereo positioning and is configurable per layer. Balance is the relative gain between each of the layers.
There are several options that can be configured from the 'f' button in the MIDI section. When you push the f(n) button then the patch and bank buttons will not select memory locations but display the on/off status of 16 algorithmic changes to the emulation. Values are saved in the synth memories. These are bristol specific modifications and may change between releases unless otherwise documented.
F(n):
f(p1): Env-1 retriggers
f(p2): Env-1 conditionals
f(p3): Env-1 attack sensitivity
f(p4): Env-2 retriggers
f(p5): Env-2 conditionals
f(p6): Env-2 attack sensitivity
f(p7): Noise per voice/layer
f(p8): Noise white/pink
f(b1): LFO-1 per voice/layer
f(b2): LFO-1 Sync to Note ON
f(b3): LFO-1 velocity tracking
f(b4): Arpeggiator retrigger
f(b5): LFO-2 velocity tracking
f(b6): NRP enable
f(b7): Debug MIDI
f(b8): Debug GUI controllersThe same function key also enables the learning function of the arpeggiator and chord memory, as explained above. When using the arpeggiator you may want to test with f(b4) enabled, it will give better control of the filter envelope.
Other differences to the original are the Hold keys on the front panel. These acted as sustain pedals however for the emulation that does not function very well. With the original the buttons were readily available whilst playing and could be used manually, something that does not work well with a GUI and a mouse. For this reason they were re-used for 'Unison Chording' discussed above. Implementing them as sustain pedals would have been an easier if less flexible option and users are advised that the bristol MIDI library does recognise the sustain controller as the logical alternative here.
Another difference would be the quality of the sound. The emulation is a lot cleaner and not as phat as the original. You might say it sounds more like something that comes from Uranus rather than Jupiter and consideration was indeed given to a tongue in cheek renaming of the emulation..... The author is allowed this criticism as he wrote the application - as ever, if you want the original sound then buy the original synth (or get Roland's own emulation?).
A few notes are required on oscillator sync since by default it will seem to be quite noisy. The original could only product a single waveform at a single frequency at any one time. Several emulators, including this one, use a bitone oscillator which generates complex waveforms. The Bristol Bitone can generate up to 4 waveforms simultaneously at different levels for 5 different harmonics and the consequent output is very rich, the waves can be slightly detuned, the pulse output can be PW modulated. As with all the bristol oscillators that support sync, the sync pulse is extracted as a positive leading zero crossing. Unfortunately if the complex bitone output is used as input to sync another oscillator then the result is far too many zero crossings to extract a good sync. For the time being you will have to simplify the sync source to get a good synchronised output which itself may be complex wave. A future release will add a sync signal from the bitone which will be a single harmonic at the base frequency and allow both syncing and synchronised waveform outputs to be arbitrary.
CRUMAR BIT-1, BIT-99, BIT-100
-----------------------------I was considering the implementation of the Korg-800, a synth I used to borrow without having due respect for it - it was a late low cost analogue having just one filter for all the notes and using the mildly annoying data entry buttons and parameter selectors. Having only one filter meant that with key tracking enabled the filter would open up as different keys were pressed, wildly changing the sound of active notes. Anyway, whilst considering how to implement the entry keys (and having features like the mouse tracking the selectors of the parameter graphics) I was reminded of this synthesizer. It was developed by Crumar but released under the name 'Bit' as the Crumar name was associated with cheesy roadrunner electric pianos at the time (also emulated by Bristol). This came out at the same time as the DX-7 but for half the price, and having the split and layer facilities won it several awards that would otherwise have gone to the incredibly innovative DX. However with the different Crumar models being released as the digital era began they kind of fell between the crack. It has some very nice mod features though, it was fun to emulate and hopefully enjoyable to play with.
As a side note, the Korg Poly-800 is now also emulated by bristol
A quick rundown of the Bit features are below. The different emulated models have slightly different default parameter values and/or no access to change them:
Two DCO with mixed waveforms.
VCF with envelope
VCA with envelope
Two LFO able to mod all other components, controlled by the wheel and key
velocity, single waveform, one had ramp and the other sawtooth options.The envelopes were touch sensitive for gain but also for attack giving plenty of expressive capabilities. The bristol envelope, when configured for velocity sensitive parameters (other than just gain) will also affect the attack rate.
The front panel had a graphic that displayed all the available parameters and to change then you had to select the "Address" entry point then use the up/down entry buttons to change its value. Bristol uses this with the addition that the mouse can click on a parameter to start entering modifications to it.
The emulation includes the 'Compare' and 'Park' features although they are a little annoying without a control surface. They work like this (not quite the same as the original): When you select a parameter and change it's value then the changes are not actually made to the active program, they just change the current sounds. The Compare button can be used to flip between the last loaded value and the current modified one to allow you to see if you prefer the sound before or after the modification.
If you do prefer the changes then to keep them you must "Park" them into the running program before saving the memory. At the time of writing the emulation emulated the double click to park&write a memory, however it also has an actual Save button since 'Save to Tape' is not a feature here. You can use park and compare over dual loaded voices: unlike the original, which could only support editing of sounds when not in split/double, this emulation allows you to edit both layers by selecting the upper/lower entry buttons and then using the sensitive panel controls to select the addressed parameters. This is not the default behaviour, you first have to edit address 102 and increment it. Then, each layer can be simultaneously edited and just needs to be parked and saved separately. The Park/Compare cache can be disabled by editing parameter DE 101, changes are then made to the synth memory and not the cache.
The memories are organised differently to the original. It had 99 memories, and the ones from 75 and above were for Split and Layered memories. Bristol can have all memories as Split or Layer. When you save a memory it is written to memory with a 'peer' program locator. When you load it with a single push on the Load button it returns to the active program, but if you double click then its 'peer' program is loaded into the other layer: press Load once to get the first program entered, then press it again - the Split/Layer will be set to the value from the first program and the second layer will be loaded. This naturally requires that the first memory was saved with Split/Layer enabled. It is advised (however not required) that this dual loading is done from the lower layer. This sequence will allow the lower layer to configure certain global options that the upper layer will not overwrite, for example the layer volumes will be select from the lower layer when the upper layer is dual loaded.
For MIDI program change then since this quirky interface cannot be emulated then the memories above 75 will be dual loaded, the rest will be single loaded.
Bristol will also emulate a bit-99 and a Bit-99m2 that includes some parameter on the front panel that were not available on the original. The engine uses the exact same algorithm for all emulations but the GUI presents different sets of parameters on the front panel. Those that are not displayed can only be accessed from the data entry buttons. The -99m2 put in a few extra features (ie, took a few liberties) that were not in the original:
DCO adds PWM from the LFO, not in the original
DCO-2 adds Sync to DCO-1, also not in the original
DCO-2 adds FM from DCO-1
DCO add PWM from Envelope
Glide has been added
DCO harmonics are not necessarily exclusive
Various envelope option for LFO
S&H LFO modulationThe reason these were added was that bristol could already do them so were quite easy to incorporate, and at least gave two slightly different emulations.
The oscillators can work slightly differently as well. Since this is a purely digital emulations then the filters are a bit weak. This is slightly compensated by the ability to configure more complex DCO. The transpose selectors (32', 16', 8' and 2') were exclusive in the original. That is true here also, however if controllers 84 and 85 are set to zero then they can all work together to fatten out the sound. Also, the controllers look like boolean however that is only the case if the data entry buttons are used, if you change the value with the data entry pot then they act more like continuous drawbars, a nice effect however the display will not show the actual value as the display remains boolean, you have to use your ear. The square wave is exclusive and will typically only function on the most recently selected (ie, typically highest) harmonic.
The same continuous control is also available on the waveform selectors. You can mix the waveform as per the original however the apparent boolean selectors are again continuous from 0.0 to 1.0. The net result is that the oscillators are quite Voxy having the ability to mix various harmonic levels of different mixable waveforms.
The stereo mode should be correctly implemented too. The synth was not really stereo, it had two outputs - one for each layer. As bristol is stereo then each layer is allocated to the left or right channel. In dual or split they came out separate feeds if Stereo was selected. This has the rather strange side effect of single mode with 6 voices. If stereo is not selected then you have a mono synth. If stereo is selected then voices will exit from a totally arbitrary output depending on which voices is allocated to each note. In contrast to the original the Stereo parameter is saved with the memory and if you dual load a split/layer it is taken from the first loaded memory only. The implementation actually uses two different stereo mixes selectable with the Stereo button: Mono is a centre pan of the signal and Stereo pans hardleft and hardright respectively. These mixes can be changed with parameters 110 to 117 using extended data entry documented below.
The default emulation takes 6 voices for unison and applies 3+3 for the split and double modes. You can request more, for example if you used '-voices 16' at startup then you would be given 8+8. As a slight anomaly you cant request 32 voices - this is currently interpreted as the default and gives you 3+3.
The bit-1 did not have the Stereo control - the controller presented is the Unison button. You can configure stereo from the extended data entry ID 110 and 111 which give the LR channel panning for 'Mono' setting, it should default to hard left and right panning. Similarly the -99 emulations do not have a Unison button, the capability is available from DE 80.
The memories for the bit-1 and bit-99 should be interchangeable however the code maintains separate directories.
There are three slightly different Bit GUI's. The first is the bit-1 with a limited parameter set as it only had 64 parameters. The second is the bit-99 that included MIDI and split options in the GUI and has the white design that was an offered by Crumar. The third is a slightly homogeneous design that is specific to bristol, similar to the black panelled bit99 but with a couple of extra parameters. All the emulations have the same parameters, some require you use the data entry controls to access them. This is the same as the original, there were diverse parameters that were not in memories that needed to be entered manually every time you wanted the feature. The Bristol Bit-99m2 has about all of the parameters selectable from the front panel however all of the emulations use the same memories so it is not required to configure them at startup (ie, they are saved). The emulation recognises the following parameters:
Data Entry 1 LFO-1 triangle wave selector (exclusive switch)
Data Entry 2 LFO-1 ramp wave selector (exclusive switch)
Data Entry 3 LFO-1 square wave selector (exclusive switch)
Data Entry 4 LFO-1 route to DCO-1
Data Entry 5 LFO-1 route to DCO-2
Data Entry 6 LFO-1 route to VCF
Data Entry 7 LFO-1 route to VCA
Data Entry 8 LFO-1 delay
Data Entry 9 LFO-1 frequency
Data Entry 10 LFO-1 velocity to frequency sensitivity
Data Entry 11 LFO-1 gain
Data Entry 12 LFO-1 wheel to gain sensitivity
Data Entry 13 VCF envelope Attack
Data Entry 14 VCF envelope Decay
Data Entry 15 VCF envelope Sustain
Data Entry 16 VCF envelope Release
Data Entry 17 VCF velocity to attack sensitivity (and decay/release)
Data Entry 18 VCF keyboard tracking
Data Entry 19 VCF cutoff
Data Entry 20 VCF resonance
Data Entry 21 VCF envelope amount
Data Entry 22 VCF velocity to gain sensitivity
Data Entry 23 VCF envelope invert
Data Entry 24 DCO-1 32' harmonic
Data Entry 25 DCO-1 16' harmonic
Data Entry 26 DCO-1 8' harmonic
Data Entry 27 DCO-1 4' harmonic
Data Entry 28 DCO-1 Triangle wave
Data Entry 29 DCO-1 Ramp wave
Data Entry 30 DCO-1 Pulse wave
Data Entry 31 DCO-1 Frequency 24 semitones
Data Entry 32 DCO-1 Pulse width
Data Entry 33 DCO-1 Velocity PWM
Data Entry 34 DCO-1 Noise level
Data Entry 35 DCO-2 32' harmonic
Data Entry 36 DCO-2 16' harmonic
Data Entry 37 DCO-2 8' harmonic
Data Entry 38 DCO-2 4' harmonic
Data Entry 39 DCO-2 Triangle wave
Data Entry 40 DCO-2 Ramp wave
Data Entry 41 DCO-2 Pulse wave
Data Entry 42 DCO-2 Frequency 24 semitones
Data Entry 43 DCO-2 Pulse width
Data Entry 44 DCO-2 Env to pulse width
Data Entry 45 DCO-2 Detune
Data Entry 46 VCA velocity to attack sensitivity (and decay/release)
Data Entry 47 VCA velocity to gain sensitivity
Data Entry 48 VCA overall gain ADSR
Data Entry 49 VCA Attack
Data Entry 50 VCA Decay
Data Entry 51 VCA Sustain
Data Entry 52 VCA Release
Data Entry 53 LFO-2 triangle wave selector (exclusive switch)
Data Entry 54 LFO-2 saw wave selector (exclusive switch)
Data Entry 55 LFO-2 square wave selector (exclusive switch)
Data Entry 56 LFO-2 route to DCO-1
Data Entry 57 LFO-2 route to DCO-2
Data Entry 58 LFO-2 route to VCF
Data Entry 59 LFO-2 route to VCA
Data Entry 60 LFO-2 delay
Data Entry 61 LFO-2 frequency
Data Entry 62 LFO-2 velocity to frequency sensitivity
Data Entry 63 LFO-2 gain
Data Entry 12 LFO-2 wheel to gain sensitivity
Data Entry 64 Split
Data Entry 65 Upper layer transpose
Data Entry 66 Lower Layer gain
Data Entry 67 Upper Layer gainThe following were visible in the Bit-99 graphics only:
Data Entry 68 MIDI Mod wheel depth
Data Entry 69 MIDI Velocity curve (0 = soft, 10=linear, 25 = hard)
Data Entry 70 MIDI Enable Debug
Data Entry 71 MIDI Enable Program Change
Data Entry 72 MIDI Enable OMNI Mode
Data Entry 73 MIDI Receive channel
Data Entry 74 MIDI Mem Search Upwards
Data Entry 75 MIDI Mem Search Downwards
Data Entry 76 MIDI Panic (all notes off)Most of the MIDI options are not as per the original. This is because they are implemented in the bristol MIDI library and not the emulation.
The following were added which were not really part of the Bit specifications so are only visible on the front panel of the bit100. For the other emulations they are accessible from the address entry buttons.
Data Entry 77 DCO-1->DCO-2 FM
Data Entry 78 DCO-2 Sync to DCO-1
Data Entry 79 Keyboard glide
Data Entry 80 Unison
Data Entry 81 LFO-1 SH
Data Entry 82 LFO-1 PWM routing for DCO-1
Data Entry 83 LFO-1 PWM routing for DCO-2
Data Entry 84 LFO-1 wheel tracking frequency
Data Entry 85 LFO-1 velocity tracking gain
Data Entry 86 LFO-1 per layer or per voice
Data Entry 87 LFO-2 SH
Data Entry 88 LFO-2 PWM routing for DCO-1
Data Entry 89 LFO-2 PWM routing for DCO-2
Data Entry 90 LFO-2 wheel tracking frequency
Data Entry 91 LFO-2 velocity tracking gain
Data Entry 92 LFO-2 per layer or per voice
Data Entry 93 ENV-1 PWM routing for DCO-1
Data Entry 94 ENV-1 PWM routing for DCO-2
Data Entry 95 DCO-1 restricted harmonics
Data Entry 96 DCO-2 restricted harmonics
Data Entry 97 VCF Filter type
Data Entry 98 DCO-1 Mix
Data Entry 99 Noise per layer
Data Entry 00 Extended data entry (above 99)Extended data entry is for all parameters above number 99. Since the displays only have 2 digits it is not totally straightforward to enter these values and they are only available in Single mode, not dual or split - strangely similar to the original specification for editing memories. These are only activated for the lower layer loaded memory, not for dual loaded secondaries or upper layer loaded memories. You can edit the upper layer voices but they will be saved with their original extended parameters. This may seem correct however it is possible to edit an upper layer voice, save it, and have it sound different when next loaded since the extended parameters were taken from a different lower layer. This is kind of intentional but if in doubt then only ever dual load voices from the lower layer and edit them in single mode (not split or layer). Per default the emulation, as per the original, will not allow voice editing in Split or Layer modes however it can be enabled with DE 102.
All the Bit emulations recognise extended parameters. They are somewhat in a disorganised list as they were built in as things developed. For the most part they should not be needed. The Bit-100 includes some in its silkscreen, for the others you can access them as follows:
deselect split or double
select addr entry
use 0..9 buttons to enter address 00
increment value to '1'. Last display should show EE (Extended Entry)
select last two digits of desired address with 0-9 buttons
change value (preferably with pot).
when finished, select address 00 again (this is now actually 100) to exit
Data Entry 100 Exit extended data entry Data Entry 101 enable WriteThru scratchpad (disables park and compare) Data Entry 102 enable layer edits on Split/Double memories. Data Entry 103 LFO-1 Sync to note on Data Entry 104 LFO-2 Sync to note on Data Entry 105 ENV-1 zero retrigger Data Entry 106 ENV-2 zero retrigger Data Entry 107 LFO-1 zero retrigger Data Entry 108 LFO-2 zero retrigger Data Entry 109 Debug enable (0 == none, 5 == persistent)
Data Entry 110 Left channel Mono gain, Lower Data Entry 111 Right channel Mono gain, Lower Data Entry 112 Left channel Stereo gain, Lower Data Entry 113 Right channel Stereo gain, Lower Data Entry 114 Left channel Mono gain, Upper Data Entry 115 Right channel Mono gain, Upper Data Entry 116 Left channel Stereo gain, Upper Data Entry 117 Right channel Stereo gain, Upper Data Entry 118 Bit-100 flag Data Entry 119 Temperature sensitivity
Data Entry 120 MIDI Channel tracking layer-2 (same/different channel) Data Entry 121 MIDI Split point tracking layer-2 (same/different split) Data Entry 122 MIDI Transpose tracking (layer-2 or both layers) N/A Data Entry 123 MIDI NRP enable
Data Entry 130 Free Memory Search Up Data Entry 131 Free Memory Search Down Data Entry 132 ENV-1 Conditional Data Entry 133 ENV-2 Conditional Data Entry 134 LFO-1 ENV Conditional Data Entry 135 LFO-2 ENV Conditional Data Entry 136 Noise white/pink Data Entry 137 Noise pink filter (enable DE 136 Pink) Data Entry 138 Glide duration 0 to 30 seconds Data Entry 139 Emulation gain level
Data Entry 140 DCO-1 Square wave gain Data Entry 141 DCO-1 Subharmonic level Data Entry 142 DCO-2 Square wave gain Data Entry 143 DCO-2 Subharmonic level
The 150 range will be incorporated when the Arpeggiator code is more stable, currently in development for the Jupiter. This is anticipated in 0.20.4:
Data Entry 150 Arpeggiator Start/Stop
Data Entry 151 Arpeggiator mode D, U/D, U or Random
Data Entry 152 Arpeggiator range 1, 2, 3, 4 octaves
Data Entry 153 Arpeggiator rate
Data Entry 154 Arpeggiator external clock
Data Entry 155 Arpeggiator retrigger envelopes
Data Entry 156 Arpeggiator poly-2 mode
Data Entry 157 Chord Enable
Data Entry 158 Chord Relearn
Data Entry 159 Sequencer Start/Stop
Data Entry 160 Sequencer mode D, U/D, U or Random
Data Entry 161 Sequencer range 1, 2, 3, 4 octaves
Data Entry 162 Sequencer rate
Data Entry 163 Sequencer external clock
Data Entry 164 Sequencer retrigger envelopes
Data Entry 165 Sequencer RelearnThe following can be manually configured but are really for internal uses only and will be overwritten when memories are saved to disk. The Split/Join flag, for example, is used by dual loading memories to configure the peer layer to load the memory in DE-198, and the stereo placeholder for configuring the stereo status of any single loaded memory.
Data Entry 193 Reserved: save bit-1 formatted memory
Data Entry 194 Reserved: save bit-99 formatted memory
Data Entry 195 Reserved: save bit-100 formatted memory
Data Entry 196 Reserved: Split/Join flag - internal use
Data Entry 197 Reserved: Stereo placeholder - internal use
Data Entry 198 Reserved: Peer memory pointer - internal use
Data Entry 199 Reserved: DCO-2 Wheel mod (masks entry 12) - internal useThe tuning control in the emulation is on the front panel rather than on the rear panel as in the original. It had a keyboard sensitivity pot however that is achieved separately with bristol using velocity curves from the MIDI control settings. The front panel rotary defaults to 0% tuning and is not saved in the memory. The front panel gain controls are also not saved in the memory and default to 0.8 at startup.
The net emulation is pretty intensive as it runs with over 150 operational parameters.
A few notes are required on oscillator sync since by default it may seem to be quite noisy. The original could only produce a single waveform at a single frequency at any one time. Several emulators, including this one, use a bitone oscillator which generates complex waveforms. The Bristol Bitone can generate up to 4 waveforms simultaneously at different levels for 5 different harmonics and the consequent output is very rich, the waves can be slightly detuned, the pulse output can be PW modulated. As with all the bristol oscillators that support sync, the sync pulse is extracted as a positive leading zero crossing. Unfortunately if the complex bitone output is used as input to sync another oscillator then the result is far too many zero crossings to extract a good sync. Code has been implemented to generate a second sync source using a side output sync wave which is then fed to a sideband sync input on the oscillator, the results are far better
Sequential Circuits Prophet Pro-One
-----------------------------------Sequential circuits released amongst the first truly polyphonic synthesisers where a group of voice circuits (5 to 10 of them) were linked to an onboard computer that gave the same parameters to each voice and drove the notes to each voice from the keyboard. The costs were nothing short of exorbitant and this lead to Sequential releasing a model with just one voice board as a mono- phonic equivalent. The sales ran up to 10,000 units, a measure of its success and it continues to be recognised alongside the Mini Moog as a fat bass synth.
The design of the Prophet synthesisers follows that of the Mini Moog. It has three oscillators one of them as a dedicated LFO. The second audio oscillator can also function as a second LFO, and can cross modulate oscillator A for FM type effects. The audible oscillators have fixed waveforms with pulse width modulation of the square wave. These are then mixed and sent to the filter with two envelopes, for the filter and amplifier.
The Pro-1 had a nice bussing matrix where 3 different sources, LFO, Filter Env and Oscillator-B could be mixed in varying amounts to two different modulation busses and each bus could then be chosen as inputs to modulation destinations. One bus was a direct bus from the mixed parameters, the second bus was under the modwheel to give configurable expressive control.
LFO:
Frequency: 0.1 to 50 Hz
Shape: Ramp/Triangle/Square. All can be selected, none selected should
give a sine waveModulations:
Source:
Filter Env amount to Direct or Wheel Mod busses
Oscillator-B amount to Direct or Wheel Mod busses
LFO to Direct amount or Wheel Mod busses
Dest:
Oscillator-A frequency from Direct or Wheel Mod busses
Oscillator-A PWM from Direct or Wheel Mod busses
Oscillator-B frequency from Direct or Wheel Mod busses
Oscillator-B PWM from Direct or Wheel Mod busses
Filter Cutoff from Direct or Wheel Mod bussesOsc-A:
Tune: +/-7 semitones
Freq: 16' to 2' in octave steps
Shape: Ramp or Square
Pulse Width: only when Square is active.
Sync: synchronise to Osc-BOsc-B:
Tune: +/-7 semitones
Freq: 16' to 2' in octave steps
Fine: +/- 7 semitones
Shape: Ramp/Triangle/Square
Pulse Width: only when Square is active.
LFO: Lowers frequency by 'several' octaves.
KBD: enable/disable keyboard tracking.Mixer:
Gain for Osc-A, Osc-B, NoiseFilter:
Cutoff: cuttof frequency
Res: Resonance/Q/Emphasis
Env: amount of modulation affecting to cutoff.
KBD: amount of keyboard tracking to cutoffEnvelopes: One each for PolyMod (filter) and amplifier.
Attack
Decay
Sustain
ReleaseSequencer:
On/Off
Record Play
Rate configured from LFOArpeggiator:
Up/Off/UpDown
Rate configured from LFOGlide:
Amount of portamento
Auto/Normal - first key will/not glide.Global:
Master Tune
Master VolumeMemories are loaded by selecting the 'Bank' button and typing in a two digit bank number followed by load. Once the bank has been selected then 8 memories from the bank can be loaded by pressing another memory select and pressing load. The display will show free memories (FRE) or programmed (PRG). There is an additional Up/Down which scan for the next program and a 'Find' key which will scan up to the next unused memory location.
The original supported two sequences, Seq1 and Seq2, but these have not been implemented. Instead the emulator will save a sequence with each memory location which is a bit more flexible if not totally in the spirit of the original.
The Envelope amount for the filter is actually 'Mod Amount'. To get the filter envelope to drive the filter it must be routed to the filter via a mod bus. This may differ from the original. Arpeggiator range is two octaves. The Mode options may not be correctly implemented due to the differences in the original being monophonic and the emulator being polyphonic. The Retrig is actually 'rezero' since we have separate voices. Drone is a Sustain key that emulates a sustain pedal. Osc-B cannot modulate itself in polyphonic mode (well, it could, it's just that it has not been coded that way). The filter envelope is configured to ignore velocity.
The default filters are quite expensive. The -lwf option will select the less computationally expensive lightweight Chamberlin filters which have a colder response but require zonks fewer CPU cycles.
Moog Voyager (Bristol "Explorer")
---------------------------------This was Robert Moog's last synth, similar in build to the Mini but created over a quarter of a century later and having far, far more flexibility. It was still monophonic, a flashback to a legendary synth but also a bit like Bjorn Borg taking his wooden tennis racket back to Wimbledon long after having retired and carbon fibre having come to pass. I have no idea who uses it and Bjorn also crashed out in the first round. The modulation routing is exceptional if not exactly clear.
The Voyager, or Bristol Explorer, is definitely a child of the Mini. It has the same fold up control panel, three and half octave keyboard and very much that same look and feel. It follows the same rough design of three oscillators mixed with noise into a filter with envelopes for the filter and amplifier. In contrast there is an extra 4th oscillator, a dedicated LFO bus also Osc-3 can still function as a second LFO here. The waveforms are continuously selected, changing gradually to each form: bristol uses a form of morphing get get similar results. The envelopes are 4 stage rather than the 3 stage Mini, and the effects routing bears no comparison at all, being far more flexible here.
Just because its funny to know, Robert Moog once stated that the most difficult part of building and releasing the Voyager was giving it the title 'Moog'. He had sold his company in the seventies and had to buy back the right to use his own name to release this synthesiser as a Moog, knowing that without that title it probably would not sell quite as well as it didn't.
Control:
LFO:
Frequency
Sync: LFO restarted with each keypress.
Fine tune +/- one note
Glide 0 to 30 seconds.Modulation Busses:
Two busses are implemented. Both have similar capabilities but one is
controlled by the mod wheel and the other is constantly on. Each bus has
a selection of sources, shaping, destination selection and amount.
Wheel Modulation: Depth is controller by mod wheel.
Source: Triwave/Ramp/Sample&Hold/Osc-3/External
Shape: Off/Key control/Envelope/On
Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
Amount: 0 to 1.
Constant Modulation: Can use Osc-3 as second LFO to fatten sound.
Source: Triwave/Ramp/Sample&Hold/Osc-3/External
Shape: Off/Key control/Envelope/On
Dest: All Osc Frequency/Osc-2/Osc-3/Filter/FilterSpace/Waveform (*)
Amount: 0 to 1.
* Destination of filter is the cutoff frequency. Filter space is the
difference in cutoff of the two layered filters. Waveform destination
affects the continuously variable oscillator waveforms and allows for
Pulse Width Modulation type effects with considerably more power since
it can affect ramp to triangle for example, not just pulse width.Oscillators:
Oscillator 1:
Octave: 32' to 1' in octave steps
Waveform: Continuous between Triangle/Ramp/Square/Pulse
Oscillator 2:
Tune: Continuous up/down 7 semitones.
Octave: 32' to 1' in octave steps
Waveform: Continuous between Triangle/Ramp/Square/Pulse
Oscillator 3:
Tune: Continuous up/down 7 semitones.
Octave: 32' to 1' in octave steps
Waveform: Continuous between Triangle/Ramp/Square/Pulse
Sync: Synchronise Osc-2 to Osc-1
FM: Osc-3 frequency modulates Osc-1
KBD: Keyboard tracking Osc-3
Freq: Osc-3 as second LFOMixer:
Gain levels for each source: Osc-1/2/3, noise and external input.Filters:
There are two filters with different configuration modes:
1. Two parallel resonant lowpass filters.
2. Serialised HPF and resonant LPF
Cutoff: Frequency of cutoff
Space: Distance between the cutoff of the two filters.
Resonance: emphasis/Q.
KBD tracking amount
Mode: Select between the two operating modes.Envelopes:
Attack
Decay
Sustain
Release
Amount to filter (positive and negative control)
Velocity sensitivity of amplifier envelope.Master:
Volume
LFO: Single LFO or one per voice (polyphonic operation).
Glide: On/Off portamento
Release: On/Off envelope release.The Explorer has a control wheel and a control pad. The central section has the memory section plus a panel that can modify any of the synth parameters as a real time control. Press the first mouse key here and move the mouse around to adjust the controls. Default values are LFO frequency and filter cutoff but values can be changed with the 'panel' button. This is done by selecting 'panel' rather than 'MIDI', and then using the up/down keys to select parameter that will be affected by the x and y motion of the mouse. At the moment the mod routing from the pad controller is not saved to the memories, and it will remain so since the pad controller is not exactly omnipresent on MIDI master keyboards - the capabilities was put into the GUI to be 'exact' to the design.
This synth is amazingly flexible and difficult to advise on its best use. Try starting by mixing just oscillator 1 through to the filter, working on mod and filter options to enrich the sound, playing with the oscillator switches for different effects and then slowly mix in oscillator 2 and 3 as desired.
Memories are available via two grey up/down selector buttons, or a three digit number can be entered. There are two rows of black buttons where the top row is 0 to 4 and the second is 5 to 9. When a memory is selected the LCD display will show whether it is is free (FRE) or programmed already (PRG).
Moog Sonic-6
------------This original design was made by an engineer who had previously worked with Moog on the big modular systems, Gene Zumchek. He tried to get Moog Inc. to develop a small standalone unit rather than the behemoths however he could not get heard. After leaving he built a synth eventually called a Sonic-5 that did fit the bill but sales volumes were rather small. He had tied up with a business manager who worked out that the volume was largely due to the name not being known, muSonics. This was quickly overcome by accident. Moog managed to run his company into rather large debt and the company folded. Bill Waytena, working with Zumcheck, gathered together the funding needed to buy the remains of the failed company and hence Moog Inc. was labeled on the rebadged Sonic-6. Zumcheck was eventually forced to leave this company (or agreed to) as he could not work with Moog. After a few modifications Bob Moog actually used this unit quite widely for lecturing on electronic music. For demonstrative purposes it is far more flexible than any of Moog's own non-modular designs and it was housed in a transport case rather than needing a shipping crate as the modular systems required.
The emulation features are given below, but first a few of the differences to the original
Added a mod wheel that can drive GenX/Y.
PWM is implemented on the oscillator B
Installed an ADSR rather than AR, selectable.
No alternative scalings - use scala file support
Not duo or dia phonic. Primarily poly with separated glide.The original was duophonic, kind of. It had a keyboard with high note and low note precedence and the two oscillators could be driven from different notes. Its not really duophony and was reportedly not nice to play but it added some flexibility to the instrument. This features was dropped largely because it is ugly to emulate in a polyphonic environment but the code still has glide only on Osc-B. It has the two LFO that can be mixed, or at full throw of the GenXY mixer they will link X->A and Y->B giving some interesting routing, two osc each with their own LFO driving the LFO from the mod wheel or shaping it with the ADSR. Playing around should give access to X driving Osc-A, then Osc-A and GenY driving Osc-B with Mod and shaping for some investigation of FM synthesis. The gruesome direct output mixer is still there, having the osc and ring-mod bypass the filter and amplifier completely (or can be mixed back into the 'actuated' signal).
There is currently no likely use for an external signal even though the graphics are there.
The original envelope was AR or ASR. The emulator has a single ADSR and a control switch to select AR (actually AD), ASR, ADSD (Minimoog envelope) or ADSR.
Generator-Y has a S/H function on the noise source for a random signal which replaced the square wave. Generator-X still has a square wave.
Modulators:
Two LFO, X and Y:
Gen X:
Tri/Ramp/Saw/Square
Tuning
Shaping from Envelope or Modwheel
Gen Y:
Tri/Ramp/Saw/Rand
Tuning
Shaping from Envelope or Modwheel
Master LFO frequency
GenXY mixer
Two Oscillators, A and B
Gen A:
Tri/Ramp/Pulse
PulseWidth
Tuning
Transpose 16', 8', 4' (*)
Mods:
Envelope
GenXY(or X)
Low frequency, High Frequency (drone), KBD Tracking
Gen B:
Tri/Ramp/Pulse
PulseWidth
Tuning
Transpose 16' 8', 4'
Mods:
Osc-B
GenXY(or Y)
PWM
GenAB mix
Ring Mod:
Osc-B/Ext
GenXY/Osc-A
Noise
Pink/White
Mixer
GenAB
RingMod
External
Noise
Filter (**)
Cutoff
Emphasis
Mods:
ADSR
Keyboard tracking
GenXY
Envelope:
AR/ASR/ADSD/ADSR
Velocity on/off
Trigger:
GenX
GenY
Kbd (rezero only)
Bypass (key gated audio)
Direct Output Mixer
Osc-A
Osc-B
RingModThe keyboard has controls for
Glide (Osc-B only)
Master Volume
PitchWheel
ModWheel (gain modifier on LFO)
Global Tuning
MultiLFO X and Y** The filter will self oscillate at full emphasis however this is less prominent at lower frequencies (much like the Moog ladder filter). The filter is also 'not quite' in tune when played as an oscillator, this will also change in a future release.
There may be a reverb on the emulator. Or there may not be, that depends on release. The PitchWheel is not saved in the memories, the unit is tuned on startup and this will maintain tuning to other instruments. The MultiLFO allow you to configure single LFO per emulation or one per voice, independently. Having polyphony means you can have the extra richness of independent LFO per voice however that does not work well if they are used as triggers, for example, you end up with a very noisy result. With single triggers for all voices the result is a lot more predictable.
The Sonic-6 as often described as having bad tuning, that probably depends on model since different oscillators were used at times. Also, different units had different filters (Zumchek used a ladder of diodes to overcome the Moog ladder of transistor patent). The original was often described as only being useful for sound effects. Personally I don't think that was true however the design is extremely flexible and the mods are applied with high gains so to get subtle sounds they only have to be applied lightly. Also, this critique was in comparison to the Mini which was not great for sound effects since it, in contrast, had very little in the way of modifiers.
The actual mod routing here is very rich. The two LFO can be mixed to provide for more complex waves and have independent signal gain from the ADSR. To go a step further it is possible to take the two mixed LFO into Osc-A, configure that as an LFO and feed it into Osc-B for some very complex mod signals. That way you can get a frequency modulated LFO which is not possible from X or Y. As stated, if these are applied heavily you will get ray guns and car alarms but in small amounts it is possible to just shape sounds. Most of the mod controls have been made into power functions to give more control at small values.
The memory panel gives access to 72 banks of 8 memories each. Press the Bank button and two digits for the bank, then just select the memory and press Load. You can get the single digit banks by selecting Bank->number->Bank. There is a save button which should require a double click but does not yet (0.30.0), a pair of buttons for searching up and down the available memories and a button called 'Find' which will select the next available free memory.
MIDI options include channel, channel down and, er, that's it.
CRUMAR TRILOGY
--------------This text is primarily that of the Stratus since the two synths were very similar. This is the bigger brother having all the same features with the added string section. There were some minor differences in the synth circuits for switchable or mixable waveforms.
This unit is a hybrid synth/organ/string combo, an early polyphonic using an organ divider circuit rather than independent VCO and having a set of filters and envelope for the synth sounds, most manufacturers came out with similar designs. The organ section was generally regarded as pretty bad here, there were just five controls, four used for the volume of 16, 8, 4 and 2 foot harmonics and a fifth for overall organ volume. The synth section had 6 voices and some quite neat little features for a glide circuitry and legato playing modes. The string section could mix 3 waveforms with vibrato on some so when mixed with the straight waveform would produce phasing.
The emulator consists of two totally separate layers, one emulating the organ circuitry and another the synth. The organ has maximum available polyphony as the algorithm is quite lightweight even though diverse liberties have been taken to beef up the sound. The synth section is limited to 6 voices unless otherwise specified at run time. The organ circuitry is used to generate the string section.
The legato playing modes affects three sections, the LFO modulation, VCO selection and glide:
LFO: this mod has a basic envelope to control the gain of the LFO using delay, slope and gain. In 'multi' mode the envelope is triggered for every note that is played and in the emulator this is actually a separate LFO per voice, a bit fatter than the original. In 'Mono' mode there is only one LFO that all voices will share and the envelope is triggered in Legato style, ie, only once for a sequence of notes - all have to be released for the envelope to recover.
VCO: The original allowed for waveform selection to alternate between notes, something that is rather ugly to do with the bristol architecture. This is replaced with a VCO selector where each note will only take the output from one of the two available oscillators and gives the notes a little more separation. The legato mode works whereby the oscillator selection is only made for the first note in a sequence to give a little more sound consistency.
Glide: This is probably the coolest feature of the synth. Since it used an organ divider circuit it was not possible to actually glide from one note to another - there are really only two oscillators in the synth section, not two per voice. In contrast the glide section could glide up or down from a selected amount to the real frequency. Selected from down with suitable values would give a nice 'blue note' effect for example. In Legato mode this is done only for the first keypress rather than all of the since the effect can be a bit over the top if applied to each keystroke in a sequence. At the same time it was possible to Sync the two oscillators, so having only one of them glide and be in sync then without legato this gave a big phasing entrance to each note, a very interesting effect. The Glide has 4 modes:
A. Both oscillators glide up to the target frequency
B. Only oscillator-2 glides up to the target frequency
C. Only oscillator-2 glides down to the target frequency
D. Both oscillators glide down to the target frequencyThese glide options with different sync and legato lead to some very unique sounds and are emulated here with only minor differences.
The features, then notes on the differences to the original:
A. Organ Section
16, 8, 4 and 2 foot harmonic strengths.
Volume.
B. Synth Section
LFO Modulation
Rate - 0.1 to 50Hz approx
Slope - up to 10 seconds
Delay - up to 10 seconds
Gain
Routing selector: VCO, VCF, VCA
Mono/Multi legato mode
Shape - Tri/Ramp/Saw/Square
Oscillator 1
Tuning
Sync 2 to 1
Octave selector
Oscillator 2
Tuning
Octave trill
Octave selector
Waveform Ramp and Square mix
Alternate on/off
Mono/Multi legato mode VCO selection
Glide
Amount up or down from true frequency
Speed of glide
Mono/Multi legato mode
Direction A, B, C, D
Filter
Cutoff frequency
Resonance
Envelope tracking -ve to +ve
Pedal tracking on/off
Envelope
Attack
Decay
Sustain
Release
Gain
C. String Section
16' 8' mix
Subharmonic gain
Attack
Release
VolumeDiverse liberties were taken with the reproduction, these are manageable from the options panel by selecting the button next to the keyboard. This opens up a graphic of a PCB, mostly done for humorous effect as it not in the least bit representative of the actual hardware. Here there are a number of surface mounted controllers. These are as below but may change by release:
P1 Master volume
P2 Organ pan P3 Organ waveform distorts P4 Organ spacialisation P5 Organ mod level J1 Organ key grooming P6 Organ tuning (currently inactive *)
P7 Synth pan P8 Synth tuning P9 Synth osc1 harmonics P10 Synth osc2 harmonics J2 Synth velocity sensitivity J3 Synth filter type P11 Synth filter tracking
P12 String pan P13 String harmonics P14 String spacialisation P15 String mod level P16 String waveform distorts
*: To make the organ tunable the keymap file has to be removed.
Master (P1) volume affects both layers simultaneously and each layer can be panned (P2/P7) and tuned (P8) separately to give phasing and spacialisation. The synth layer has the default frequency map of equal temperament however the organ section uses a 2MHz divider frequency map that is a few cents out for each key. The Trilogy actually has this map for both layers and that can easily be done with the emulator, details on request.
It is currently not possible to retune the organ divider circuit, it has a private microtonal mapping to emulate the few percent anomalies of the divider circuit and the frequencies are predefined. The pot is still visible in P6 and can be activated by removing the related microtonal mapping file, details from the author on request.
Diverse liberties were taken with the Organ section since the original only produced 4 pure (infinite bandwidth) square waves that were mixed together, an overly weak result. The emulator adds a waveform distort (P3), an notched control that produces a pure sine wave at centre point. Going down it will generate gradually increasing 3rd and 5th harmonics to give it a squarey wave with a distinct Hammond tone. The distortion actually came from the B3 emulator which models the distort on the shape of the Hammond tonewheels themselves. Going up from centre point will produce gradually sharper sawtooth waves using a different phase distortion.
Organ spacialisation (P4) will separate out the 4 harmonics to give them slightly different left and right positions to fatten out the sound. This works in conjunction with the mod level (P5) where one of the stereo components of each wave is modified by the LFO to give phasing changes up to vibrato.
The organ key grooming (J1) will either give a groomed wave to remove any audible clicks from the key on and off events or when selected will produce something akin to a percussive ping for the start of the note.
The result for the organ section is that it can produce some quite nice sounds reminiscent of the Farfisa range to not quite Hammond, either way far more useful than the flat, honking square waves. The original sound can be made by waveform to a quarter turn or less, spacialisation and mod to zero, key grooming off.
The synth has 5 modifications at the first release. The oscillator harmonics can be fattened at the top or bottom using P9 and P10, one control for each oscillator, low is more bass, high is more treble. Some of the additional harmonics will be automatically detuned a little to fatten out the sound as a function of the -detune parameter defaulting to 100.
The envelope can have its velocity sensitively to the filter enabled or disabled (J2) and the filter type can be a light weight filter for a thinner sound but at far lower CPU load (J3).
The filter keyboard tracking is configurable (P11), this was outside of the spec of the Trilogy however it was implemented here to correct the keyboard tracking of the filter for all the emulations and the filter should now be playable. The envelope touch will affect this depending on J2 since velocity affects the cut off frequency and that is noticeable when playing the filter. This jumper is there so that the envelope does not adversely affect tuning but can still be used to have the filter open up with velocity if desired.
The mod application is different from the original. It had a three way selector for routing the LFO to either VCO, VCA or VCF but only a single route. This emulation uses a continuous notched control where full off is VCO only, notch is VCF only and full on is VCA however the intermediate positions will route proportional amounts to two components.
The LFO has more options (Ramp and Saw) than the original (Tri and Square).
The extra options are saved with each memory however they are only loaded at initialisation and when the 'Load' button is double-clicked. This allows you to have them as global settings or per memory as desired. The MemUp and MemDown will not load the options, only the main settings.
VCO mod routing is a little bit arbitrary in this first release however I could not find details of the actual implementation. The VCO mod routing only goes to Osc-1 which also takes mod from the joystick downward motion. Mod routing to Osc-2 only happens if 'trill' is selected. This seemed to give the most flexibility, directing the LFO to VCF/VCA and controlling vibrato from the stick, then having Osc-2 separate so that it can be modified and sync'ed to give some interesting phasing.
As of the first release there are possibly some issues with the oscillator Sync selector, it is perhaps a bit noisy with a high content of square wave. Also, there are a couple of minor improvements that could be made to the legato features but they will be done in a future release. They regard how the glide is applied to the first or all in a sequence of notes.
The joystick does not always pick up correctly however it is largely for presentation, doing actual work you would use a real joystick or just use the modwheel (the stick generates and tracks continuous controller 1 - mod). The modwheel tracking is also a bit odd but reflects the original architecture - at midpoint on the wheel there is no net modulation, going down affects VCO in increasing amounts and going up from mid affect the VCF. The control feels like it should be notched however generally that is not the case with mod wheels.
A few notes are required on oscillator sync since by default it will seem to be quite noisy. The original could only product a single waveform at a single frequency at any one time. Several emulators, including this one, use a bitone oscillator which generates complex waveforms. The Bristol Bitone can generate up to 4 waveforms simultaneously at different levels for 5 different harmonics and the consequent output is very rich, the waves can be slightly detuned, the pulse output can be PW modulated. As with all the bristol oscillators that support sync, the sync pulse is extracted as a positive leading zero crossing. Unfortunately if the complex bitone output is used as input to sync another oscillator then the result is far too many zero crossings to extract a good sync. For the time being you will have to simplify the sync source to get a good synchronised output which itself may be complex wave. A future release will add a sync signal from the bitone which will be a single harmonic at the base frequency and allow both syncing and synchronised waveform outputs to be arbitrary. For the Trilogy this simplification of the sync waveform is done automatically by the Sync switch, this means the synchronised output sounds correct but the overall waveform may be simpler.
CRUMAR STRATUS
--------------This unit is a hybrid synth/organ combo, an early polyphonic synth using an organ divider circuit rather than independent VCO and having a set of filters and envelope for the synth sounds, most manufacturers came out with similar designs. The organ section was generally regarded as pretty bad here, there were just five controls, four used for the volume of 16, 8, 4 and 2 foot harmonics and a fifth for overall organ volume. The synth section had 6 voices and some quite neat little features for a glide circuitry and legato playing modes.
The emulator consists of two totally separate layers, one emulating the organ circuitry and another the synth. The organ has maximum available polyphony as the algorithm is quite lightweight even though diverse liberties have been taken to beef up the sound. The synth section is limited to 6 voices unless otherwise specified at run time.
The legato playing modes affects three sections, the LFO modulation, VCO selection and glide:
LFO: this mod has a basic envelope to control the gain of the LFO using delay, slope and gain. In 'multi' mode the envelope is triggered for every note that is played and in the emulator this is actually a separate LFO per voice, a bit fatter than the original. In 'Mono' mode there is only one LFO that all voices will share and the envelope is triggered in Legato style, ie, only once for a sequence of notes - all have to be released for the envelope to recover.
VCO: The original allowed for waveform selection to alternate between notes, something that is rather ugly to do with the bristol architecture. This is replaced with a VCO selector where each note will only take the output from one of the two available oscillators and gives the notes a little more separation. The legato mode works whereby the oscillator selection is only made for the first note in a sequence to give a little more sound consistency.
Glide: This is probably the coolest feature of the synth. Since it used an organ divider circuit it was not possible to actually glide from one note to another - there are really only two oscillators in the synth section, not two per voice. In contrast the glide section could glide up or down from a selected amount to the real frequency. Selected from down with suitable values would give a nice 'blue note' effect for example. In Legato mode this is done only for the first keypress rather than all of the since the effect can be a bit over the top if applied to each keystroke in a sequence. At the same time it was possible to Sync the two oscillators, so having only one of them glide and be in sync then without legato this gave a big phasing entrance to each note, a very interesting effect. The Glide has 4 modes:
A. Both oscillators glide up to the target frequency
B. Only oscillator-2 glides up to the target frequency
C. Only oscillator-2 glides down to the target frequency
D. Both oscillators glide down to the target frequencyThese glide options with different sync and legato lead to some very unique sounds and are emulated here with only minor differences.
The features, then notes on the differences to the original:
A. Organ Section
16, 8, 4 and 2 foot harmonic strengths.
Volume.
B. Synth Section
LFO Modulation
Rate - 0.1 to 50Hz approx
Slope - up to 10 seconds
Delay - up to 10 seconds
Gain
Routing selector: VCO, VCF, VCA
Mono/Multi legato mode
Shape - Tri/Ramp/Saw/Square
Oscillator 1
Tuning
Sync 2 to 1
Octave selector
Oscillator 2
Tuning
Octave trill
Octave selector
Waveform Ramp and Square mix
Alternate on/off
Mono/Multi legato mode VCO selection
Glide
Amount up or down from true frequency
Speed of glide
Mono/Multi legato mode
Direction A, B, C, D
Filter
Cutoff frequency
Resonance
Envelope tracking -ve to +ve
Pedal tracking on/off
Envelope
Attack
Decay
Sustain
Release
GainDiverse liberties were taken with the reproduction, these are manageable from the options panel by selecting the button next to the keyboard. This opens up a graphic of a PCB, mostly done for humorous effect as it not in the least bit representative of the actual hardware. Here there are a number of surface mounted controllers. These are as below but may change by release:
P1 Master volume
P2 Organ pan P3 Organ waveform distorts P4 Organ spacialisation P5 Organ mod level J1 Organ key grooming P6 Organ tuning (currently inactive *)
P7 Synth pan P8 Synth tuning P9 Synth osc1 harmonics P10 Synth osc2 harmonics J2 Synth velocity sensitivity J3 Synth filter type P11 Synth filter tracking
*: To make the organ tunable the keymap file has to be removed.
Master (P1) volume affects both layers simultaneously and each layer can be panned (P2/P7) and tuned (P8) separately to give phasing and spacialisation. The synth layer has the default frequency map of equal temperament however the organ section uses a 2MHz divider frequency map that is a few cents out for each key. The Stratus actually has this map for both layers and that can easily be done with the emulator, details on request.
It is currently not possible to retune the organ divider circuit, it has a private microtonal mapping to emulate the few percent anomalies of the divider circuit and the frequencies are predefined. The pot is still visible in P6 and can be activated by removing the related microtonal mapping file, details from the author on request.
Diverse liberties were taken with the Organ section since the original only produced 4 pure (infinite bandwidth) square waves that were mixed together, an overly weak result. The emulator adds a waveform distort (P3), an notched control that produces a pure sine wave at centre point. Going down it will generate gradually increasing 3rd and 5th harmonics to give it a squarey wave with a distinct Hammond tone. The distortion actually came from the B3 emulator which models the distort on the shape of the Hammond tonewheels themselves. Going up from centre point will produce gradually sharper sawtooth waves using a different phase distortion.
Organ spacialisation (P4) will separate out the 4 harmonics to give them slightly different left and right positions to fatten out the sound. This works in conjunction with the mod level (P5) where one of the stereo components of each wave is modified by the LFO to give phasing changes up to vibrato.
The organ key grooming (J1) will either give a groomed wave to remove any audible clicks from the key on and off events or when selected will produce something akin to a percussive ping for the start of the note.
The result for the organ section is that it can produce some quite nice sounds reminiscent of the Farfisa range to not quite Hammond, either way far more useful than the flat, honking square waves. The original sound can be made by waveform to a quarter turn or less, spacialisation and mod to zero, key grooming off.
The synth has 5 modifications at the first release. The oscillator harmonics can be fattened at the top or bottom using P9 and P10, one control for each oscillator, low is more bass, high is more treble. Some of the additional harmonics will be automatically detuned a little to fatten out the sound as a function of the -detune parameter defaulting to 100.
The envelope can have its velocity sensitively to the filter enabled or disabled (J2) and the filter type can be a light weight filter for a thinner sound but at far lower CPU load (J3).
The filter keyboard tracking is configurable (P11), this was outside of the spec of the Stratus however it was implemented here to correct the keyboard tracking of the filter for all the emulations and the filter should now be playable. The envelope touch will affect this depending on J2 since velocity affects the cut off frequency and that is noticeable when playing the filter. This jumper is there so that the envelope does not adversely affect tuning but can still be used to have the filter open up with velocity if desired.
The mod application is different from the original. It had a three way selector for routing the LFO to either VCO, VCA or VCF but only a single route. This emulation uses a continuous notched control where full off is VCO only, notch is VCF only and full on is VCA however the intermediate positions will route proportional amounts to two components.
The LFO has more options (Ramp and Saw) than the original (Tri and Square).
The extra options are saved with each memory however they are only loaded at initialisation and when the 'Load' button is double-clicked. This allows you to have them as global settings or per memory as desired. The MemUp and MemDown will not load the options, only the main settings.
VCO mod routing is a little bit arbitrary in this first release however I could not find details of the actual implementation. The VCO mod routing only goes to Osc-1 which also takes mod from the joystick downward motion. Mod routing to Osc-2 only happens if 'trill' is selected. This seemed to give the most flexibility, directing the LFO to VCF/VCA and controlling vibrato from the stick, then having Osc-2 separate so that it can be modified and sync'ed to give some interesting phasing.
As of the first release there are possibly some issues with the oscillator Sync selector, it is perhaps a bit noisy with a high content of square wave. Also, there are a couple of minor improvements that could be made to the legato features but they will be done in a future release. They regard how the glide is applied to the first or all in a sequence of notes.
The joystick does not always pick up correctly however it is largely for presentation, doing actual work you would use a real joystick or just use the modwheel (the stick generates and tracks continuous controller 1 - mod). The modwheel tracking is also a bit odd but reflects the original architecture - at midpoint on the wheel there is no net modulation, going down affects VCO in increasing amounts and going up from mid affect the VCF. The control feels like it should be notched however generally that is not the case with mod wheels.
A few notes are required on oscillator sync since by default it will seem to be quite noisy. The original could only product a single waveform at a single frequency at any one time. Several emulators, including this one, use a bitone oscillator which generates complex waveforms. The Bristol Bitone can generate up to 4 waveforms simultaneously at different levels for 5 different harmonics and the consequent output is very rich, the waves can be slightly detuned, the pulse output can be PW modulated. As with all the bristol oscillators that support sync, the sync pulse is extracted as a positive leading zero crossing. Unfortunately if the complex bitone output is used as input to sync another oscillator then the result is far too many zero crossings to extract a good sync. For the time being you will have to simplify the sync source to get a good synchronised output which itself may be complex wave. A future release will add a sync signal from the bitone which will be a single harmonic at the base frequency and allow both syncing and synchronised waveform outputs to be arbitrary. For the Stratus this simplification of the sync waveform is done automatically by the Sync switch, this means the synchronised output sounds correct but the overall waveform may be simpler.
KORG POLY 800
-------------This is a low cost hybrid synth, somewhere between the Korg PolySix and their Mono/Poly in that is polyphonic but only has one filter rather than one per voice that came with the PolySix. It may have also used organ divider circuits rather than individual oscillators - it did not have glide as a feature which would be indicative of a divider circuit.
It featured 8 oscillators that could be applied as either 4 voices with dual osc or 8 voices with a single osc. The architecture was verging on the interesting since each oscillator was fed into an individual envelope generator (described below) and then summed into the single filter, the filter having another envelope generator, 9 in total. This lead to cost reduction over having a filter per voice however the single filter leads to breathing, also discussed below. The envelopes were digitally generated by an on-board CPU.
The control panel has a volume, global tuning control and a 'Bend' control that governs the depth of the pitch bend from the joystick and the overall amount of DCO modulation applied by the joystick. There is no sequencer in this emulation largely because there are far better options now available than this had but also due to a shortage of on-screen real estate.
The Poly, Chord and Hold keys are emulated, hold being a sustain key. The Chord relearn function works follows:
Press the Hold key
Press the Chord key with 2 seconds
Press the notes on the keyboard (*)
Press the Chord key againAfter that the single chord can be played from a single note as a monophonic instrument. The Chord is saved individually with each memory.
The keypanel should function very similar to the original. There is a Prog button that selects between Program selection or Parameter selection and an LED should show where the action is. There is the telephone keyboard to enter program or parameters numbers and an up/down selector for parameter value. The Bank/Hold selector also works, it fixes the bank number so programs can be recalled from a single bank with a single button press. The Write function is as per the original - Press Write, then two digits to save a memory.
The front panel consists of a data entry panel and a silkscreen of the parameter numbers (this silkscreen is active in the emulation). Fifty parameters are available from the original instrument:
DE 11 DCO1 Octave transposition +2 octaves
DE 12 DCO1 Waveform Square or Ramp
DE 13 DCO1 16' harmonic
DE 14 DCO1 8' harmonic
DE 15 DCO1 4' harmonic
DE 16 DCO1 2' harmonic
DE 17 DCO1 level
DE 18 DCO Double (4 voice) or Single (8 voice)
DE 21 DCO2 Octave transposition +2 octaves
DE 22 DCO2 Waveform Square or Ramp
DE 23 DCO2 16' harmonic
DE 24 DCO2 8' harmonic
DE 25 DCO2 4' harmonic
DE 26 DCO2 2' harmonic
DE 27 DCO2 level
DE 31 DCO2 semitone transpose
DE 32 DCO2 detune
DE 33 Noise level
DE 41 Filter cutoff frequency
DE 42 Filter Resonance
DE 43 Filter Keyboard tracking off/half/full
DE 44 Filter Envelope polarity
DE 45 Filter Envelope amount
DE 46 Filter Envelope retrigger
DE 48 Chorus On/Off
DE 51 Env-1 DCO1 Attack
DE 52 Env-1 DCO1 Decay
DE 53 Env-1 DCO1 Breakpoint
DE 54 Env-1 DCO1 Slope
DE 55 Env-1 DCO1 Sustain
DE 56 Env-1 DCO1 Release
DE 61 Env-2 DCO2 Attack
DE 62 Env-2 DCO2 Decay
DE 63 Env-2 DCO2 Breakpoint
DE 64 Env-2 DCO2 Slope
DE 65 Env-2 DCO2 Sustain
DE 66 Env-2 DCO2 Release
DE 71 Env-3 Filter Attack
DE 72 Env-3 Filter Decay
DE 73 Env-3 Filter Breakpoint
DE 74 Env-3 Filter Slope
DE 75 Env-3 Filter Sustain
DE 76 Env-3 Filter Release
DE 81 Mod LFO Frequency
DE 82 Mod Delay
DE 83 Mod DCO
DE 84 Mod VCF
DE 86 MIDI channel
DE 87 MIDI program change enable
DE 88 MIDI OMNIOf these 25 parameters, the emulation has changed 88 to be OMNI mode rather than the original sequence clock as internal or external. This is because the sequencer function was dropped as explained above.
Additional to the original many of the controls which are depicted as on/off are actually continuous. For example, the waveform appears to be either square or ramp. The emulator allows you to use the up/down Value keys to reproduce this however if you use the potentiometer then you can gradually move from one wave to the next. The different harmonics are also not on/off, you can mix each of them together with different amounts and if you configure a mixture of waveforms and a bit of detune the sound should widen due to addition of a bit of phasing within the actual oscillator.
The envelope generators are not typical ADSR. There is an initial attack from zero to max gain then decay to a 'Breakpoint'. When this has been reached then the 'Slope' parameter will take the signal to the Sustain level, then finally the release rate. The extra step of breakpoint and slope give plenty of extra flexibility to try and adjust for the loss of a filter per voice and the emulation has a linear step which should be the same as the original. The ninth envelope is applied to the single filter and also as the envelope for the noise signal level.
The single filter always responded to the highest note on the keyboard. This gives a weaker overall sound and if playing with two hands then there is a noticeable effect with keytracking - left hand held chords will cause filter breathing as the right hand plays solos and the keyboard tracking changes from high to low octaves. Note that the emulator will implement a single filter if you select DE 46 filter envelope retrigger to be single trigger, it will be played legato style. If multiple triggers are selected then the emulator will produce a filter and envelope for each voice.
Bristol adds a number of extra parameters to the emulator that are not available from the mouse on the silkscreen and were not a part of the design of the poly800. You have to select Prog such that the LED is lit next to the Param display, then select the two digit parameter from the telephone keyboard:
DE 28 DCO Sync 2 to 1
DE 34 DCO-1 PW
DE 35 DCO-1 PWM
DE 36 DCO-2 PW
DE 37 DCO-2 PWM
DE 38 DCO temperature sensitivity
DE 67 DCO Glide
DE 85 Mod - Uni/Multi per voice or globally
DE 57 Envelope Touch response
DE 47 Chorus Parameter 0
DE 58 Chorus Parameter 1
DE 68 Chorus Parameter 2
DE 78 Chorus Parameter 3If DataEntry 28 is selected for oscillator sync then LFO MOD to DCO-1 is no longer applied, it only goes to DCO-2. This allows for the interesting sync modulated slow vibrato of DCO-2. The LFO mod is still applied via the joystick.
DE 38 global detune will apply both temperature sensitivity to each oscillator but also fatten out the harmonics by detuning them independently. It is only calculated at 'note on' which can be misleading - it has no effect on existing notes which is intentional if misleading.
DE 57 is a bitmask for the three envelopes to define which ones will give a response to velocity with a default to '3' for velocity tracking oscillator gain:
value DEG1 DEG2 DEG3
DCO1 DCO2 FILT
0 - - -
1 V - -
2 - V -
3 V V -
4 - - V
5 V - V
6 - V V
7 V V VThis gives some interesting velocity tracking capabilities where just one osc can track velocity to introduce harmonic content keeping the filter at a fixed cutoff frequency. Having a bit of detune applied globally and locally will keep the sound reasonably fat for each oscillator.
The filter envelope does not track velocity for any of the distributed voices, this was intentional since when using high resonance it is not desirable that the filter cutoff changes with velocity, it tends to be inconsistently dissonant.
If you want to use this synth with controller mappings then map the value entry pot to your easiest to find rotary, then click the mouse on the membrane switch to select which parameter you want to adjust with that control each time. The emulator is naturally not limited to just 4/8 voices, you can request more in which case single oscillator will give you the requested number of voices and double will give you half that amount.
The Bristol Poly-800 is dedicated to Mark.
Baumann BME-700
---------------This unusual German synth had a build volume of about 500 units and only one useful source of information could be found on it: a report on repair work for one of the few existing examples at www.bluesynths.com. The BME systems were hand built and judging by some reports on build quality may have been sold in kit form. The unit was produced in the mid 1970's.
The synth has a very interesting design, somewhat reminiscent of the Moog Sonic and Explorer synths. It has two modulating LFO with fairly high top frequency, two filter and two envelopes. The envelopes are either AR or ASR but they can be mixed together to generate amongst other features an ADSR, very innovative. There is only one oscillator but the sound is fattened out by the use of two parallel filters, one acting as a pure resonator and the other as a full VCF.
The synth has been left with a minimum of overhead. There are just 8 memory
locations on the front panel with Load, Save and Increment buttons and one
panel of options to adjust a few parameters on the oscillator and filters. It
is possible to get extra memories by loading banks with -load: if you request
starting in memory #21 the emulator will stuff 20 into the bank and 1 into the
memory location. There is no apparent MIDI channel selector, use -channel
A. MOD
Two LFO:
frequency from 0.1 to 100 Hz
Triangle and Square wave outputs
Mix control
Mod-1/2 into the VCO FM
Env-1/Mod-2 into the VCO FM
B. Oscillator
Single VCO
Glide 0 to 10s, on/off.
PW Man: 5 to 50% duty cycle
Auto depth:
Envelope-1
Mod-1, Mod-1/2, Tri/Square
Vibrato depth
Tuning
8', 4', 16' transposition
Shape
continuous control from Square to Tri wave.
Mix of noise or VCO output
C. Res Filter
Sharp (24db/Oct), Flat (12dB/Oct)
5 frequency switches
D. Envelopes
Two envelopes
Rise time
Fall Time
AR/ASR selector
Two independent mixes of Env, for VCF and VCA.
E. Filter
Frequency
Resonance
Env/Mod selector
Modulation
KBD tracking
Mod-1 or Mod-2, Tri/Square
F. Amplifier
Mix resonator/filter.
Volume
Mod depth
Mod-1 or Mod-2, Tri/SquareThe oscillator is implemented as a non-resampling signal generator, this means it uses heuristics to estimate the wave at any given time. The harmonic content is a little thin and although the generation method seems to be correct in how it interprets signal ramps and drains from an analogue circuit this is one area of improvement in the emulator. There are options to produce multiple waveforms described below.
The resonant filter is implemented with a single Huovilainen and actually only runs at 24dB/Oct. There are controls for remixing the different taps, a form of feedforward and when in 'Flat' mod there is more remixing of the poles, this does generate a slower roll off but gives the signal a bit more warmth than a pure 12dB/Oct would.
There is a selector in the Memory section to access some options:
G. Options
LFO
Synchronise wave to key on events
Multi LFO (per voice).
Oscillator
Detune (temperature sensitivity)
Multi - remix 8' with 16' or 4'.
Noise
Multi Noise (per voice).
White/Pink
Pink Filter
ResFilter
Sharp Resonance/Remix
Flat Resonance/Remix
Envelope
Velocity Sensitive
Rezero for note on
Gain
Filter
Remix
KBD tracking depthThe emulator probably gives the best results with the following:
startBristol -bme700 -mono -hnp -retrig -channel 1
This gives a monophonic emulation with high note preference and multiple triggers.
The options from section G are only loaded under two circumstances: at system start from the first selected memory location and if the Load button is given a double-click. All other memory load functions will inherit the settings that are currently active.
Bristol BassMaker
-----------------The BassMaker is not actually an emulator, it is a bespoke sequencer design but based on the capabilities of some of the early analogue sequencers such as the Korg SQ-10. Supplying this probably leaves bristol open to a lot of feature requests for sequencer functionality and it is stated here that the BassMaker is supposed to be simple so excess functionality will probably be declined as there are plenty of other sequencing applications that can provide a richer feature set.
The main page gives access to a screen of controls for 16 steps and a total of 4 pages are available for a total of 64 steps. The pages are named 'A' through 'D'. Each step has 5 options:
Note: one octave of note selection
Transpose: +/- one octave transposition of the note.
Volume: MIDI note velocity
Controller: MIDI modulation, discussed further below
Triggers: Note On/Off enablersThe trigger button gives 4 options indicated by the LED:
off: note on/off are sent
red: only send note_on
green: only send note_off
yellow: do not send note on/offThe 'Controllers' setting has multiple functions which can be selected from the menu as explained below. The options available are as follows:
Send semitone tuning
Send glide rate
Send modwheel
Send expression pedal (controller value)
Send Note: the controller will be 12 discrete steps as per the 'Note'
setting and this note will be sent on the Secondary MIDI channel.The semitone tuning and glide work for the majority of the emulations. Some do not support fine tune controls (Vox, Hammond, others). If you are missing these capabilities for specific emulators raise a change request on Sourceforge.net.
At the top of the window there is a panel to manage the sequencer. It has the following functions:
Speed: step rate through the notes
DutyCycle: ratio of note-on to note-off
Start/Pause
Stop: stop and return to first step/page
Direction:
Up
Down
Up/Down
Random
Select: which of the pages to include in the sequence.
Edit: which page is currently displayed to be edited.
Memory:
0..9 key entry buttons, 1000 memories available
Load
Save: double-click to save current sequence
Menu Panel
Up, Down menu
Function (return to previous level)
Enter: enter submenu or enter value if in submenuThe menu consists of several tables, these can be stepped through using the Up and Down arrows to move through the menu and the 'Enter' arrow to select a sub menu or activate any option. The 'Fn' button returns one level:
Memory:
Find next free memory upwards
Find next memory upwards
Find next memory downwards
Copy:
Copy current edit page to 'A', 'B', 'C' or 'D'.
Control - Set the control value to send:
semitone tuning
glide rate
modwheel
expression pedal (controller value)
note events
First MIDI channel
Primary MIDI channel for note events
Second MIDI channel
Secondary MIDI channel when 'Control' configured to 'Note' events.
Global Transpose
Transpose the whole sequence up or down 12 semitones
Clear - configure default value for all of the:
Notes to zero
Transpose to zero (midpoint)
Volume to 0.8
Control to midpoint
Triggers to on/offAs of the first release in 0.30.8 large parts of the Controllers functionality was only lightly tested. If you do not get the results you anticipate you may require a fix.
Bristol SID
-----------In release 0.40 bristol introduced a piece of code that emulated the Commodore C64 6581 SID chip. The interface uses byte settings of the 31 chip registers to be close to the original plus some floating point IO for extracting the audio signal and configuring some analogue parameters and the 'softSID' is clocked by the sample extraction process.
The chip uses integer maths and logic for the oscillators, ring mod, sync and envelopes and emulates the analogue components of the 6581 with floating point code, for the filter and S/N generation.
The oscillators will run as per the original using a single phase accumulator and 16 bit frequency space. All the waveforms are extracted logically from the ramp waveform generated by the phase accumulation. Sync and RingMod are also extracted with the same methods. The noise generation is XOR/add as per the original, however the noise signal will not degenerate when mixing waveforms. The output waves are ANDed together. The bristol control register has an option for Multi waveforms and when selected each oscillator will have its own phase accumulator, can have a detune applied and will be mixed by summation rather than using an AND function.
The envelope is an 8 bit up/down counter with a single gate bit. All the 4 bit parameters give rates taken from the chip specifications including the slightly exponential decay and release. Attack is a linear function and the sustain level can only be decreased when active as the counter also refuses to count back up when passed its peak.
The filter implements a 12dB/Octave multimode Chamberlin filter providing LP, BP and HP signals. This is not the best filter in the world however neither was the original. An additional 24dB/Octave LP filter has been added, optionally available and with feedforward to provide 12/18dB signals. Between them the output can be quite rich.
The emulator provides some control over the 'analogue' section. The S/N ratio can be configured from inaudible (just used to prevent denormal of the filter) up to irritating levels. Oscillator leakage is configurable from none up to audible levels and the oscillator detune is configurable in cents although this is a digital parameter and was not a part of the original.
Voice-3 provides an 8 bit output of its oscillator and envelope via the normal output registers and the otherwise unused X and Y Analogue registers contain the Voice-1 and Voice-2 oscillator output.
The bristol -sid emulator uses two softSID, one generating three audio voices and a second one providing modulation signals by sampling the voice-3 osc and env outputs and also by configuring voice-1 to generate noise to the output, resampling this noise and gating it from voice-3 to get sample and hold. This would have been possible with the original as well if the output signal were suitably coupled back on to one of the X/Y_Analogue inputs.
The emulator has several key assignment modes. The emulator is always just monophonic but uses internal logic to assign voices. It can be played as a big mono synth with three voices/oscillators, polyphonically with all voices either sounding the same or optionally configured individually, and as of this release a single arpeggiating mode - Poly-3. Poly-3 will assign Voice-1 to the lowest note, voice-3 to the highest note and will arpeggiate Voice-2 through all other keys that are pressed with a very high step rate. This is to provide some of the sounds of the original C64 where fast arpeggiation was used to sounds chords rather than having to use all the voices. This first implementation does not play very well in Poly-3, a subsequent release will probably have a split keyboard option where one half will arpeggiate and the other half will play notes.
This is NOT a SID player, that would require large parts of the C64 to also be emulated and there are plenty of SID players already available.
Bristol again thanks Andrew Coughlan, here for proposing the implementation of a SID chip which turned out to be a very interesting project.
For the sake of being complete, given below is the verbose help output
A synthesiser emulation package.
You should start this package with the startBristol script. This script
will start up the bristol synthesiser binaries evaluating the correct
library paths and executable paths. There are emulation, synthesiser,
operational and GUI parameters:
Emulation:
-mini - Moog Mini
-explorer - Moog Voyager
-voyager - Moog Voyager Electric Blue
-memory - Moog Memory
-sonic6 - Moog Sonic 6
-mg1 - Moog/Realistic MG-1 Concertmate
-hammond - Hammond module (deprecated, use -b3)
-b3 - Hammond B3 (default)
-prophet - Sequential Circuits Prophet-5
-pro52 - Sequential Circuits Prophet-5/FX
-pro10 - Sequential Circuits Prophet-10
-pro1 - Sequential Circuits Pro One
-rhodes - Fender Rhodes Mark-I Stage 73
-rhodesbass - Fender Rhodes Piano Bass
-roadrunner - Crumar Roadrunner electric piano
-bitone - Crumar bit 01
-bit99 - Crumar bit 99
-bit100 - Crumar bit + mods
-stratus - Crumar Stratus synth/organ combo
-trilogy - Crumar Trilogy synth/organ/string combo
-obx - Oberheim OB-X
-obxa - Oberheim OB-Xa
-axxe - ARP Axxe
-odyssey - ARP Odyssey
-arp2600 - ARP 2600
-solina - ARP/Solina String Ensemble
-polysix - Korg Polysix
-poly800 - Korg Poly-800
-monopoly - Korg Mono/Poly
-ms20 - Korg MS-20 (unfinished: -libtest only)
-vox - Vox Continental
-voxM2 - Vox Continental Super/300/II
-juno - Roland Juno-60
-jupiter - Roland Jupiter-8
-bme700 - Baumann BME-700
-bm - Bristol bassmaker sequencer
-dx - Yamaha DX7
-cs80 - Yamaha CS-80 (unfinished)
-sidney - Commodore-64 SID chip synth
-melbourne - Commodore-64 SID polyphonic synth (unfinished)
-granular - Granular synthesiser (unfinished)
-aks - EMS Synthi A (unfinished)
-mixer - 16 track mixer (unfinished: -libtest only)
Synthesiser:
-voices <n> - operate with a total of 'n' voices (32)
-mono - operate with a single voice (-voices 1)
-lnp - low note preference (-mono)
-hnp - high note preference (-mono)
-nnp - no/last note preference (-mono)
-retrig - monophonic note logic legato trigger (-mono)
-lvel - monophonic note logic legato velocity (-mono)
-channel <c> - initial MIDI channel selected to 'c' (default 1)
-lowkey <n> - minimum MIDI note response (0)
-highkey <n> - maximum MIDI note response (127)
-detune <%> - 'temperature sensitivity' of emulation (0)
-gain <gn> - emulator output signal gain (default 1)
-pwd <s> - pitch wheel depth (2 semitones)
-velocity <v> - MIDI velocity mapping curve (510) (-mvc)
-glide <s> - MIDI glide duration (5)
-emulate <name> - search for the named synth or exit
-register <name> - name used for JACK and ALSA device registration
-lwf - emulator lightweight filters
-nwf - emulator default filters
-wwf - emulator welterweight filters
-hwf - emulator heavyweight filters
-blo <h> - maximum # band limited harmonics (31)
-blofraction <f> - band limiting Nyquist fraction (0.8)
-scala <file> - read the scala .scl tonal mapping table
User Interface:
-quality <n> - colour cache depth (bbp 2..8) (6)
-grayscale <n> - colour or BW display (0..5) (0 = colour)
-antialias <n> - antialias depth (0..100%) (30)
-aliastype <s> - antialias type (pre/texture/all)
-opacity <n> - opacity of the patch layer 20..100% (50)
-scale <s> - initial windowsize, fs = fullscreen (1.0)
-width <n> - the pixel width of the GUI window
-autozoom - flip between min and max window on Enter/Leave
-raise - disable auto raise on max resize
-lower - disable auto lower on min resize
-rud - constrain rotary tracking to up/down
-pixmap - use the pixmap interface rather than ximage
-dct <ms> - double click timeout (250 ms)
-tracking - disable MIDI keyboard tracking in GUI
-load <m> - load memory number 'm' (default 0)
-import <pathname> - import memory from file into synth
-mbi <m> - master bank index (0)
-activesense <m> - active sense rate (2000 ms)
-ast <m> - active sense timeout (15000 ms)
-mct <m> - MIDI cycle timeout (50 ms)
-ar|-aspect - ignore emulator requested aspect ratio
-iconify - start with iconified window
-window - toggle switch to enable X11 window interface
-cli - enable command line interface
-libtest - GUI test option, engine not invoked
GUI keyboard shortcuts:
<Ctrl> 's' - save settings to current memory
<Ctrl> 'l' - (re)load current memory
<Ctrl> 'x' - exchange current with previous memory
<Ctrl> '+' - load next memory
<Ctrl> '-' - load previous memory
<Ctrl> '?' - show emulator help information
<Ctrl> 'h' - show emulator help information
<Ctrl> 'r' - show application readme information
<Ctrl> 'k' - show keyboard shortcuts
<Ctrl> 'p' - screendump to /tmp/<synth>.xpm
<Ctrl> 't' - toggle opacity
<Ctrl> 'o' - decrease opacity of patch layer
<Ctrl> 'O' - increase opacity of patch layer
<Ctrl> 'w' - display warranty
<Ctrl> 'g' - display GPL (copying conditions)
<Shift> '+' - increase window size
<Shift> '-' - decrease window size
<Shift> 'Enter'- toggle window between full screen size
'UpArrow' - controller motion up (shift key accelerator)
'DownArrow' - controller motion down (shift key accelerator)
'RightArrow' - more controller motion up (shift key accelerator)
'LeftArrow' - more controller motion down (shift key accelerator)
Operational:
General:
-engine - don't start engine (connect to existing engine)
-gui - don't start GUI (only start engine)
-server - run engine as a permanent server
-daemon - run engine as a detached permanent server
-log - redirect diagnostic to $HOME/.bristol/log
-syslog - redirect diagnostic to syslog
-console - log all messages to console (must be 1st option)
-cache <path> - memory and profile cache location (~/.bristol)
-exec - run all subprocesses in background
-debug <1-16> - debugging level (0)
-readme [-<e>] - show readme [for emulator <e>] to console
-glwf - global lightweight filters - no overrides
-host <h> - connect to engine on host 'h' (localhost)
-port <p> - connect to engine on TCP port 'p' (default 5028)
-quiet - redirect diagnostic output to /dev/null
-gmc - open a MIDI connection to the brighton GUI
-oss - use OSS defaults for audio and MIDI
-alsa - use ALSA defaults for audio and MIDI (default)
-jack - use JACK defaults for audio and MIDI
-jsmuuid <UUID>- JACK session unique identifier
-jsmfile <path>- JACK session setting path
-jsmd <ms> - JACK session file load delay (5000)
-session - disable session management
-jdo - use separate JACK clients for audio and MIDI
-osc - use OSC for control interface (unfinished)
-forward - disable MIDI event forwarding globally
-localforward - disable emulator GUI->engine event forwarding
-remoteforward - disable emulator engine->GUI event forwarding
-o <filename> - Duplicate raw audio output data to file
-nrp - enable NPR support globally
-enrp - enable NPR/DE support in engine
-gnrp - enable NPR/RP/DE support in GUI
-nrpcc <n> - size of NRP controller table (128)
Audio driver:
-audio [oss|alsa|jack] - audio driver selection (alsa)
-audiodev <dev> - audio device selection
-count <samples> - sample period count (256)
-outgain <gn> - digital output signal gain (default 4)
-ingain <gn> - digital input signal gain (default 4)
-preload <periods> - configure preload buffer count (default 4)
-rate <hz> - sample rate (44100)
-priority <p> - audio RT priority, 0=no realtime (75)
-autoconn - attempt JACK port auto-connect
-multi <c> - register 'c' IO channels (jack only)
-migc <f> - multi IO input gain scaling (jack only)
-mogc <f> - multi IO output gain scaling (jack only)
MIDI driver:
-midi [oss|[raw]alsa|jack] - MIDI driver selection (alsa)
-mididev <dev> - MIDI device selection
-seq - use the ALSA SEQ interface (default)
-mididbg - MIDI debug-1 enable
-mididbg2 - MIDI debug-2 enable
-sysid - MIDI SysEx system identifier
LADI driver (level 1 compliant):
-ladi brighton - only execute LADI in GUI
-ladi bristol - only execute LADI in engine
-ladi <memory> - LADI state memory index (1024)
Audio drivers are PCM/PCM_plug or JACK. MIDI drivers are either OSS/ALSA
rawmidi interface, or ALSA SEQ. Multiple GUIs can connect to the single
audio engine which then operates multitimbrally.
The LADI interfaces does not use a state file but a memory in the normal
memory locations. This should typically be outside of the range of the
select buttons for the synth and the default of 1024 is taken for this
reason.
Examples:
startBristol
Print a terse help message.
startBristol -v -h
Hm, if you're reading this you found these switches already.
startBristol -mini
Run a Minimoog using ALSA interface for audio and MIDI seq. This is
equivalent to all the following options:
-mini -alsa -audiodev plughw:0,0 -midi seq -count 256 -preload 8
-port 5028 -voices 32 -channel 1 -rate 44100 -gain 4 -ingain 4
startBristol -alsa -mini
Run a Minimoog using ALSA interface for audio and MIDI. This is
equivalent to all the following options:
-mini -audio alsa -audiodev plughw:0,0 -midi alsa -mididev hw:0
-count 256 -preload 8 -port 5028 -voices 32 -channel 1 -rate 44100
startBristol -explorer -voices 1 -oss
Run a Moog Explorer as a monophonic instrument, using OSS interface for
audio and MIDI.
startBristol -prophet -channel 3
Run a Prophet-5 using ALSA for audio and MIDI on channel 3.
startBristol -b3 -count 512 -preload 2
Run a Hammond B3 with a buffer size of 512 samples, and preload two
such buffers before going active. Some Live! cards need this larger
buffer size with ALSA drivers.
startBristol -oss -audiodev /dev/dsp1 -vox -voices 8
Run a Vox Continental using OSS device 1, and default MIDI device
/dev/midi0. Operate with just 8 voices.
startBristol -b3 -audio alsa -audiodev plughw:0,0 -seq -mididev 128.0
Run a B3 emulation over the ALSA PCM plug interface, using the ALSA
sequencer over client 128, port 0.
startBristol -juno &
startBristol -prophet -channel 2 -engine
Start two synthesisers, a Juno and a Prophet. Both synthesisers
will be executed on one engine (multitimbral) with 32 voices between
them. The Juno will be on default MIDI channel (1), and the Prophet on
channel 2. Output over the same default ALSA audio device.
startBristol -juno &
startBristol -port 5029 -audio oss -audiodev /dev/dsp1 -mididev /dev/midi1
Start two synthesisers, a Juno on the first ALSA soundcard, and a
Minimoog on the second OSS soundcard. Each synth is totally independent
and runs with 32 voice polyphony (looks nice, not been tested).The location of the bristol binaries can be specified in the BRISTOL environment variable. Private memory and MIDI controller mapping files can be found in the directory BRISTOL_CACHE and defaults to $HOME/.bristol
Setting the environment variable BRISTOL_LOG_CONSOLE to any value will result in the bristol logging output going to your console window without formatted timestamps
Korg Inc. of Japan is the rightful owner of the Korg and Vox trademarks, and the Polysix, Mono/Poly, Poly-800, MS-20 and Continental tradenames. Their own Vintage Collection provides emulations for a selection of their classic synthesiser range, this product is in no manner related to Korg other than giving homage to their great instruments.
Bristol is in no manner associated with any of the original manufacturers of any of the emulated instruments. All names and trademarks are property of their respective owners.
author: Nick Copeland
email: nickycopeland@hotmail.com
http://bristol.sourceforge.net