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dzannotti / junox

An emulator of a Roland Juno 60
https://dzannotti.github.io/junox/
GNU General Public License v3.0
22 stars 6 forks source link

DCO LFO #23

Open dzannotti opened 5 years ago

dzannotti commented 5 years ago

The dco lfo seems to be in the right range, but the mod value is waaay off (probably it's not even linear)

pendragon-andyh commented 5 years ago

It will be something like +-3.5 octaves (like we did on filter). The old analogue synth used CV (control voltage) a LOT. so it was common to see stuff like 1 volt per octave. I will see if I can confirm the max modulation range for you.

dzannotti commented 5 years ago

the range seems to be of 1 tone and seems to match the sounds, but the slider to amount is currently wrong (atm is linear) (i've to lower waaay down compared to patches to get the same sounds)

pendragon-andyh commented 5 years ago

Answer is in 106 service notes. +-400 cents.

dzannotti commented 5 years ago

That's great, i think the real error is here https://github.com/dzannotti/junox/blob/master/src/junox/voice.js#L64

this.patch.lfo is the [0..1] slider, and i don't think it should be linear

I mean currently it does +-200 cents, so for sure that needs fixing too

pendragon-andyh commented 5 years ago

The code for actual pitch modulation looks ok - looks like current code is -100 to +100 cents (I am review code on small tablet so may be wrong).

Are you saying that the effect of the slider on the depth should not be linear? So:

If this is the case then I have a couple of wav files that I can analyse.

pendragon-andyh commented 5 years ago

Makes me wonder if the other modulation sliders (for the VCF) are non-linear. The VCF is really hard for me to accurately measure. We will need to do by-ear comparisons for that.

I had a play with the current demo ... it definitely feels (without me checking mu JU06) like I have specified the "5" part of the slider equation too low, and the "14" too high. You might want to experiment with ("10" and "12") or ("20" and "10") - to see if it feels better.

At the moment I plan to get my JU-06 driven from midi at the weekend so I can start to compare its filter settings (which are supposed to be very close to the 60/106).