Is Karplus–Strong possible?

Algorithm development and general DSP issues

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dslocum
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Is Karplus–Strong possible?

Post by dslocum »

Is it possible to do a Karplus–Strong algorithm that tracks an analog keyboard? I want to play with physical modeling.
frank
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Post by frank »

I doubt it, the chip was designed as an effects engine and using it to track a keyboard would be difficult. You might be able to produce tones using an LFSR to generate the noise and gating it to make it a burst into a filter and delay loop but I've never tried that.
Frank Thomson
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diydsp
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Post by diydsp »

To be clear - I think this chip would be great for Karplus-Strong itself -- - It has excellent register-level support for buffer manipulation. One could probably handle numerous voices and/or do interesting linear/non-linear things with each delay line.

Tracking the analog keyboard though isn't something it's designed for. Tracking a keyboard from its audio is always a difficult problem. If you can get note information into the chip another way (audio adc input?) the FV-1 would be useful for Karplus-Strong.
dslocum
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Post by dslocum »

Thanks.

I should have been more clear. I didn't mean tracking the audio from a keyboard. I was thinking of using the CV inputs with an analog synth keyboard that puts out 1 V / Octave.

Does the ADC have enough resolution and accuracy for that? I seem to recall that there were some exponential functions built into the chip. Could those be used to advantage with the CV inputs?
frank
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Post by frank »

POT inputs are 10-bit.

You can apply the log and exp to the ACC. Since the POT inputs can be read into the ACC you can apply any function to the values read from POT inputs.
Frank Thomson
Experimental Noize
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