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Very cool stuff, Richard. BTW, I'd love to hear of a source of the mentioned Neil Young CD! Anyone? David Lee Myers http://www.pulsewidth.com -------------------------------------------------------------------------- "Ourobouros" CD of new Feedback Music available now on Pulsewidth! In NYC at Downtown Music, Kim's Mondo, and Other Music, and through Forced Exposure, Anomalous, Wayside, Electronic Music Foundation, Recommended, and Staalplaat. on 3/20/01 6:41 PM, Richard Zvonar at zvonar@zvonar.com wrote: > The behavior and tonal characteristics of feedback are dependent such > things as the resonant characteristics of the acoustic (or virtual > acoustic) space it inhabits and the transfer functions of the > transducers the signal passes through. You can play around with the > use of different microphones, different loudspeakers, different > rooms, and the use of filters, reverbs, and other signal processors. > It's interesting to set up a sound system with multiple microphones > and multiple speakers in a naturally reverberant space and then play > around with the mixer levels. You can do a similar thing by > crosscoupling feedback paths within a mixer but substituting multiple > reverb units for the physcial room. > > I did some interesting work a while back with feedback and a > Fairlight Voicetracker pitch-to-MIDI convertor. A microphone fed the > Voicetracker and the Voicetracker controlled a synthesizer. The > synthesizer sound was fed through a digital reverb with a rather long > decay time and that was fed into the room through a set of > loudspeakers. Because the reverb time was long, there was a > phenomenon I call "resonance memory" - certain pitch resonances would > build up in the reverb and be detected by the Voicetracker. If > several different pitches were sounding at once, then Voicetracker > would jump from one to another in often interesting ways. The first > piece I did like this used one hand held microphone. I initiated the > process by making one short vocal sound into the mic and then I waved > the mic slowly through the speaker's sound field. I did several > passes, with different synthesizer sounds on each track, so there was > a kind of organic growth process as each new track added to the > source material for the Voicetracker process. > > I also worked with acoustic instrumentalists and a singer, using > several mics sent via the mixer's aux send to the Voicetracker. The > main signal "heard" by the Voicetracker came from whichever > instrument or voice was being fed to it at the time, but there was > also some bleed-through of the reverberated synthesizer sound. One > particularly interesting effect came from miking a marimba with two > mics. The percussionist played sustained tremolos and varied the > harmonic intervals. This generated some interesting arpeggiations. > Another interesting effect came from solo bassoon. This instrument > can often "lose" its fundamental frequency, with most of the timbre > coming from the overtones. The player could control these timbral > changes and achieved a fine degree of control over the response of > the Voicetracker. > > > I realize these pitch-to-MIDI techniques are somewhat removed from > your initial query about feedback, but there IS a certain conceptual > and physical acoustics commonality. > > > Also, on feedback music: I recall that a few years ago Neil Young > did a limited edition CD compilation of guitar feedback from live > gigs.