🚀 go-pugleaf

Bob Masta wrote:
> However, there are some "electrophonic" effects that
> have been known as curiosities for about 100 years.
> By proper voltage application to tissue, you can actually
> make the tissue vibrate, creating regular old acoustic
> sound which can then be heard by a normal ear.

At the U. of Rochester around 1980, Rick Razdan (later founded ISCAN)
and I played with a crude Neurophone down in the basement of the vision
psych department.  A Wavetek signal generator fed a rack-mount power
op-amp, which fed a few turns wrapped around a TV flyback transformer
with floating secondary.   The electrodes were copper screen embedded
between thin plexiglas with silicone caulk.  Tune the generator to the
flyback's resonance, then either switch on the Wavetek's internal 1KHz
modulator, or pipe some audio into the VCG connector.

It worked!   With the electrodes clamped to our heads, we could hear
very clear sound.  But I noticed while clamping the electrode plates to
my arm, I could hear the sound coming from the electrodes.   By simply
touching my fingertips gently to one of the plates, I could hear the
sound coming from my fingertips.  We turned out the lights and saw a
purple glow surrounding our fingertips in contact with the plastic.

So the Neurophone is actually a "Kirlian Photography" setup!   It's
also a "plasma tweeter," since it creates a glow discharge, then
creates sound by modulating the amount of wattage feeding that plasma.

No doubt the device was injecting plenty of sound directly into the
tissues in contact with the electrodes, so the sound would travel
around inside.  However, I could NOT hear any sound when I clamped the
device to my arm and then plugged my ears.  If our amp had far more
power, perhaps I could have heard the flesh-conducted sound injected
into my arm and travelling up my neck to my ears..

When wearing the electrode plates on our ears, I suppose that the sound
mostly came from the contact point between our ear tissues and the
plastic.   It behaved somewhat unexpectedly, since most of the sound
was apparently being injected into the flesh of our outer ears, then
travelling internally to our eardrums or perhaps directly to the
cochlea, rather than travelling through the air path.  No matter how
the plates were positioned, the sound seemed to be coming from the same
direction.  By touching the plate to any part of our ears, we heard the
same clear loud audio signal.  Flesh conduction is weird.  Underwater
noises, with your body being the "water."

But best of all, we got to watch each other with 30,000V electrodes
strapped to our heads!


((((((((((((((((((((((( (  (    (o)    )  ) )))))))))))))))))))))))
William J. Beaty              http://staff.washington.edu/wbeaty/
Research Engineer             UW Chem Dept,  Bagley Hall RM74
beaty@chemwashingtonedu     Box 351700, Seattle, WA 98195-1700
ph:206-543-6195 fax:206-685-8665