Removing tonality: antitune

Question

What kind of processing would you apply to an audio track to remove its tonal quality (its pitch), leaving sound with the same texture as the original but ambiguous pitch? For example, a drum sound is mostly texture without much tonality.

For another analogy, think of a process similar to "auto tune" called "anti tune".

Answer 1

A couple possibilities:

• Ring Modulation. For an example, see the sample audio for Mickey Delp's ring modular module.
• Vocoding — use a noise source (or some other sound source of ambiguous pitch) for the carrier. For an example, see the track "Uranium" on Kraftwerk's album Radio-Activity.

Answer 2

I'm not sure you will be able to keep the same texture but eliminate pitch.

We recognize sounds as having a pitch when that pitch is stable enough to recognize. Taking your drum example, drum sounds often sweep down in pitch (kicks and toms) or are enveloped white noise (snares and high-hats). In either case, you don't have a constant, identifiable pitch. But if you were to keep a kick drum's pitch constant, you'd end up with a very different texture.

It is pretty easy to play with these sound parameters in a modular environment like Pure Data.