Analog vs digital pitch shifting?
The way I understand it is that analog pitch shifting is comparable to resampling in the digital domain. Only that the analog pitch shift works "continuously", whereas resampling obviously works on a discrete valued digital signal.
However, is time-preserving pitch shifting purely a digital technique?
Analog vs digital pitch shifting?
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- KVRian
- Topic Starter
- 1097 posts since 28 May, 2010 from Finland
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- KVRAF
- 3080 posts since 17 Apr, 2005 from S.E. TN
This article by Sean Costello is good and also supplies more links for study.
https://valhalladsp.com/2010/05/04/pitc ... e-digital/
I have seen analog bucket brigade unidirectional pitch shifters which work "near identical" to early eventide digital shifters, except they sounded even crappier than the early eventides. The early eventide pitch shifters sounded purt bad even a semitone shifted sharp or flat, but sounded good for "a few cents shift doubling".
Long ago somebody gave me a single rackspace analog bbd shifter which had apparently been targeted at the karaoke market. I kept it for awhile then gave it away to someone else. As best I recall it had a stepped rotary knob capable of something like +/- 6 semitones but was noisy and sounded bad even at +/- 1 semitone shift, and laughably bad near the extremes. Maybe fabulous for a low fi grunge effect though, dunno.
Look up how the early eventides did it, discrete digital chips and no cpu. Same thing can be done with triangle LFO, analog VCAs for crossfading, two channels of BBD delay line.
Long ago I wrote several variants of the same algorithm in computer code, as have many people. Tortured mutant variations of delay-based chorus. It is easy to get something working with glitchy warbly results and rather difficult to make a good sounding shifter with that approach, either in analog or digital. In my experience anyway. Maybe somebody has made a good sounding shifter based on that idea.
Well, probably either analog or digital implementation could sound quite nice for a few cents unidirectional shift for doubling type effects or maybe even fine-tuning a track that is only a few cents out of tune. Just not promising for shifting by semitones for clean transpose effects.
https://valhalladsp.com/2010/05/04/pitc ... e-digital/
I have seen analog bucket brigade unidirectional pitch shifters which work "near identical" to early eventide digital shifters, except they sounded even crappier than the early eventides. The early eventide pitch shifters sounded purt bad even a semitone shifted sharp or flat, but sounded good for "a few cents shift doubling".
Long ago somebody gave me a single rackspace analog bbd shifter which had apparently been targeted at the karaoke market. I kept it for awhile then gave it away to someone else. As best I recall it had a stepped rotary knob capable of something like +/- 6 semitones but was noisy and sounded bad even at +/- 1 semitone shift, and laughably bad near the extremes. Maybe fabulous for a low fi grunge effect though, dunno.
Look up how the early eventides did it, discrete digital chips and no cpu. Same thing can be done with triangle LFO, analog VCAs for crossfading, two channels of BBD delay line.
Long ago I wrote several variants of the same algorithm in computer code, as have many people. Tortured mutant variations of delay-based chorus. It is easy to get something working with glitchy warbly results and rather difficult to make a good sounding shifter with that approach, either in analog or digital. In my experience anyway. Maybe somebody has made a good sounding shifter based on that idea.
Well, probably either analog or digital implementation could sound quite nice for a few cents unidirectional shift for doubling type effects or maybe even fine-tuning a track that is only a few cents out of tune. Just not promising for shifting by semitones for clean transpose effects.
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- KVRAF
- 3080 posts since 17 Apr, 2005 from S.E. TN
Another way to try it in analog or digital-- Dunno if anybody ever made devices based on it. Since about everything has been done, surely somebody built one or wrote a plugin. You would structure it with two or more overlapped bi-directional shifters as with early eventide. But rather than use sets of bbd or digital delay line, use sets of phase shifters.
Various old tube based 1950's phase shifter true vibrato gadgets were made for guitar and organ. No moving parts. Just use more than one circuits similar to the old vibrato circuits, and crossfade between them to only shift up or only shift down. Transpose rather than vibrato.
You could do the same thing with transistors or digital code. Might be even trickier to get a good quality result, but maybe as an effect it could be more charming/quirky than crossfaded delay lines?
Various old tube based 1950's phase shifter true vibrato gadgets were made for guitar and organ. No moving parts. Just use more than one circuits similar to the old vibrato circuits, and crossfade between them to only shift up or only shift down. Transpose rather than vibrato.
You could do the same thing with transistors or digital code. Might be even trickier to get a good quality result, but maybe as an effect it could be more charming/quirky than crossfaded delay lines?
