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External signal processor module to control Werkstatt

PostPosted: Tue Jul 11, 2017 8:02 pm
by Raspy

I made an Extenal Signal Processor module by using Arduino or STM32 microprocessor board + some extra circuit, in order to control Werkstatt by other synthesizers.
By using ESP, you can use most of synthesizers as controller of Werkstatt. ESP analyzes pitch of the sound and convert it to CV/Gate signal. As long as you use simple wave shape, pitch trucking is excellent.
Here is a short demo.
It's Arduino, and after this demo I ported this program to ST Nucleo board which is cheaper and faster. It trucks better than Arduino.

Currently I'm using it just for personal fun but if you guys are interested, I will make a kit. Please let me know what you think!

Re: External signal processor module to control Werkstatt

PostPosted: Wed Jul 12, 2017 10:45 am
by grenert
That seems like it could be really useful! Could you even control it with a non-keyboard instrument (horn, clarinet, guitar) as long as the signal level was correct?
Are you using the VCA input or the gate out connector on the Werkstatt? If you used the VCA input, the Werkstatt could then exactly follow the amplitude of the external signal (don't convert the signal to a gate).

Re: External signal processor module to control Werkstatt

PostPosted: Wed Jul 12, 2017 1:45 pm
by Raspy

Thanks for the reply.
First of all, I made a new version of the demo (using STM32 Nucleo)
Please check it!

Unfortunately the input signal have to be simple enough to track.
Like you said, initially I planned to accept wider range of signals (mainly for guitar) but tracking quality never got "practical" level. I mean the quality was something like experimental thing like ESP port in Korg MS20. I gave it up and store to shelf for a while.

Then I changed direction to focus more simple waveshape like Sine, Triangle or Saw. In result I could reach the quality more than experimental level. Acceptable pitch tracking accuracy and latency.

I connect it CV to VCO EXP and GATE OUT(IN) only, not using VCA input. It doesn't have CV signal for VCA at this point. I may add it if there is a way to add it without adding much components.

Re: External signal processor module to control Werkstatt

PostPosted: Mon Jul 17, 2017 4:33 pm
by Raspy
It's off topic, but I noticed following things during my experiment.

1. Gate out / in can be used as VCO gain control like VCA IN but still attack and decay works.
By changing Gate In continuously, I could make full futures ADSR envelope curve.

2. Maybe someone mentioned this in this forum in the past. Basically VCO out is way too high and that makes clipping at LFO stage.
That defines aggressive Werkstatt's sound character but that ruins sweet ladder filter tone as well.
I can test this because I'm using the module I made, but similar thing can be done easily
by adding some circuit to lower VCO out, I think.