GK 13 pin

[kelargo]

Hi

Can the signals from GK 13 pin on a guitar be used as input signals to a CV synth?

here's a diagram of the cable I'm talking about - My link

From what I understand, the cable connector is originally used to go from a guitar into a Roland guitar synth, which would create a MIDI signal, to become a controller, to drive a synth.. But this connector has six analog signals for each string.. and I'm wondering why use MIDI, when a CV synth would possible be interesting?

just wondering. thanks.

[jojjelito]

Sure they could, but not without jumping through some interesting hoops first.

What you have in the GK cable is basically audio and a couple of extra signals. This audio would have to be treated so that you can get a synth oscillator to track the frequency of the guitar string. This frequency is preferably the root note (or fundamental frequency) that the pick-up is fed.

So, here you need a fast root note detection. Ok, then convert the frequency to some CV to control an oscillator somewhere, or just use the root note to reset a ramp wave which then has a different amplitude depending on how far the ramp got. Worst case: did it top out because the input frequency was lower than that of the ramp? Either way, you would then have to compensate the amplitude to be more or less constant and this is now your slave oscillator.

In analog you use some kind of f-v (frequency to voltage) process. There are special chips for this even, but you'd still need to figure out the fundamental frequency first. Guitar synths are complex beasts and the task of root frequency detection and so forth is usually done with proprietary DSP algorithms these days. Or, you get a guitar that speaks MIDI, but that's another beast.

You'd need some special sauce to make this process fool-proof. Then output MIDI or CV.

Take a peek at Wikipedia and follow the links for some pointers, this is a complex problem

Edited December 28, 2012 by jojjelito