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jpcima / string-machine

Digital model of electronic string ensemble instrument
Boost Software License 1.0
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Completing the model #2

Open jpcima opened 5 years ago

jpcima commented 5 years ago

I've quickly checked the model against Solina schematics, identified major lacking elements. (answering also @farvardin on completeness of implementation)

In the original, the 4' and 8' sections are known as violin and viola respectively.

  1. missing: brass section (trumpet/horn) It's needed to identify what does the formant circuit folllowing the oscillator. It has a set of switches which seem to affect a characteristic of a filter. Capture du 2019-07-15 19-18-01

  2. missing: bass section It's cello and contrabass, and it has a more complex circuitry, of which I'm not fully sure how it fits in the model. It's made from various parts: low-tone selection, clipper, trigger suppression, bass sustain, and low-pass filter

Capture du 2019-07-15 19-26-22 Capture du 2019-07-15 19-27-10

jpcima commented 5 years ago

Some ltspice sims of formant filters, having switch in horn or trumpet position.

formant.zip

Horn Trumpet

Peak approximately at 1.445 kHz (horn), and 4.445 kHz (trumpet)

jpcima commented 5 years ago

Attempt at the formant filter in the brass branch

jpcima commented 4 years ago

Note to self:

The service manual of ARP Omni has a description of circuits in plain english ! Including an explanation of bass parts.

http://www.synthfool.com/docs/Arp/ArpOmni/ARP_Omni_2480_service_manual.pdf