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Re: How's the pitch-to-midi of Roland VP-70?



At 11:19 AM -0700 5/7/03, Herb wrote:
>Wonderfully terrible is how I'd describe the VP70.
>The VP70 is a very ambitious mid-80's vocal processor that often fails in
>very interesting ways. The pitch-to-MIDI is amusingly poor. It's fun to
>hear it trying to make sense out of speech, drums or chords.

This sort of behavior seems to be endemic to most, if not all, pitch 
trackers. I've done a bit of work with the Fairlight Voicetracker, 
which originally sold in the $2000+ range. It also freaks out in 
amusing and musically useful ways when fed complex inputs. I chose to 
pursue this as a compositional strategy.

One of the situations that really gets a pitch tracker going is when 
it is part of a feedback loop. If you use the MIDI output to drive a 
synthesizer or sampler and then allow the pitch tracker to "hear" 
that signal it will begin to pick up different components of the 
sound, such as resonances and upper harmonics. This can be greatly 
enhanced (or "aggravated") by adding a lot of reverberation to the 
mix. I once did a piece where I initiated the pitch tracking process 
with a short "pop" and then walked around the room waving the 
microphone through the sound field of the loudspeakers. I was able to 
generate (and control to a reasonable extent) slow pitch glides. I 
did this in several passes, overdubbing into a sequencer and playing 
back the different tracks with a variety of timbres. The combination 
of sounds, with a 10 second reverb time providing a sort of "memory" 
for the system, resulted in fairly coherent melodic material, largely 
based on complex arpeggiations.

Other strategies can involve acoustic instruments that are either 
polyphonic or that have mutable spectra. As an example of the first 
case, I did a performance with two percussionists playing xylophone 
and marima, again with a lot of reverb. They started playing 
sustained unisons and octaves, then introduced fifths, major thirds, 
and increasingly dissonant intervals. The generated melody 
progressed similarly from simple to complex behavior.

I also got very interesting results with bassoon, and instrument 
which typically produces stronger overtones than fundamental pitch. 
The player, composer Chuck Holdeman, quickly learned to manipulate 
this effect and dynamically adjusted the timbre of sustained tones to 
cause the Voicetracker to jump merrily among the harmonics.

Have fun!
-- 

______________________________________________________________
Richard Zvonar, PhD
(818) 788-2202
http://www.zvonar.com
http://RZCybernetics.com