Pitch Tracking for CV?

[Mr. Lime]

Thinking about ring modulators and their practical use for guitars has brought me to the topic, that pitch tracking might be a thing.

I know about the Pigrtonix Ringmaster which has a mono-phonic tracker which I would guess is archived through a CD4046 PLL IC as the sound reminds me on some Parasit Studio pedals I wired up.

Is there a commercial product or an easy DIY circuit of a pitch tracker that could replace a LFO or envelope detector you guys can recommend?

A digital solution on an ATTINY85 would be fine as well but I'm not aware of something like that..

anotherjim once posted this:


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[ElectricDruid]

I would say that I've never seen this done sufficiently accurately outside serious DSP. These days, "serious DSP" fits into a little pedal and need not cost serious money, but (in my opinion) it's still something that's outside the realm of possibility for analogue circuits.

Sure, there have been efforts in this direction ever since the 1970's (Didn't one of the Korg Synths have something like this? MS20?) but if they worked brilliantly, we'd all have heard of it already. They don't. They work *ok* in a limited way on a limited range of input signals. PLLs are in that category. Their capture range is fairly narrow, and the wider you make it, the longer it takes them to capture the signal. It's a bit like analogue octaving - if you play in a particular way to get the best out of it, it can be reasonably convincing. As soon as you push further than that, forget it. It all falls to pieces, and unless that's part of the effect you're after, it's a mess.

Other people may be more positive about this than me, but personally, I don't really believe it can be done effectively.

T.

[Mark Hammer]

Tom is right.  The bandwidth is the problem.  Why?  Because such convertors generally want more than one cycle of the input signal to reliably detect pitch. When the note fundamental is, say 200hz, two peaks and troughs takes enough time (10msec) that the lag between picking and hearing a sonic change is disruptive to the fluidity of one's playing.  Throw older pitch-2-MIDI into the mix and that lag is extended a bit longer.  It's not disruptive if the CV/gate is used to produce a "pad", with a longer rise time.  But if the intent is to produce a sound with a fast attack/rise time - something more percussive - that relatively brief conversion time is quite acceptable.  IF one could rely on pitch-detection via the harmonics, rather than the fundamental, that would speed up the detection and conversion.

I have two etched and populated boards with Robert Penfold's P2V convertor, but have not managed to get them to work.  All those microscopic solder bridges and "ragged" etches that produce similarly microscopic undesired connections between traces are the bane of my existence.

[Mr. Lime]

Thank you very much for the impressions.
I've read that people had problems getting the P2V to work.

I consider buying a Pigtronix Ringmaster to check out what they came up with and how good it works especially with controling other effects.
Is there any DSP solution avialable allowing pitch tracking with a CV out?

[moosapotamus]

...just throwing in some big props for the Pigtronix Ringmaster. Love it! Tracks incredibly well, IMO. However, have not yet taken advantage of the CV Out. Have to think about what/where I could use that...