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Re: good feedback vs. bad feedback, or the revenge of the 10dollar microphone.

Very cool stuff, Richard.  BTW, I'd love to hear of a source of the
mentioned Neil Young CD!  Anyone?

David Lee Myers
"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

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.