MOTM

Radio Shack makes a $3 piezo buzzer that I modify to create
transducers to amplify acoustic instruments.  They sound nasty, so I
like them.

I have one mounted on an old guitar at the bridge. I'm going to hook
it to the output of my MOTM and see what happens.  I'll report back,
maybe with an mpg...

Mike

--- In motm@y..., <groovyshaman@s...> wrote:
> Hi Elhardt,
> 
> Very interesting.  I'm thinking there are basically two
possibilities here:
> 
> 1) Use a voltage-to-movement transducer to induce vibration in the
strings,
> causing the instrument to "play" itself.  Of course, without
fretting, the
> instrument would be somewhat limited to the fundamental frequencies and
> associated harmonics of the four strings (along with body
resonances.)  You
> could string the violin with steel strings and use electro-magnets
to induce
> movement.  Another option could be to use one or more piezo-transducers
> mounted to the bridge.  If you are thinking of amplifying the resultant
> signal, you could mount a microphone or piezo-pickup on the bridge
and pass
> the signal thru a pre-amp back to the synth.  Pickup location will
be very
> sensitive, I'm sure.
> 
> 2) Use the violin body as a resonating filter of sorts; to pass an audio
> signal "through" the body of the violin and recover the resultant
signal.  A
> voltage-to-movement transducer could be used at audio frequencies to
> "excite" the body resonances, and a movement-to-voltage transducer could
> then pick up the resultant signal.  Probably the optimal inducer
would be a
> very small full-range speaker mounted inside (!) the body.  The best
pickup
> would probably be a mic.  Another idea, you could mount a metal
plate to the
> bridge and use an electro-magnet to set the bridge into motion (but how
> would you mount this? hmm).  Obviously, mounting locations would
have the
> greatest effect on the response of this filter; there are so many
different
> resonance components.
> 
> There are quite a few challenging issues here: obtaining the appropriate
> signal levels for both inducing and recovery, transducer types, mounting
> hardware and location, etc.  Sounds like fun!  I would be very
curious to
> hear how this experiment turns out.  FYI, I have dabbled somewhat with
> piezo-transducer pickups on a cello, passing the resultant signal
thru my
> MOTM rig.
> 
> Cheers,
> George
> 
> ----- Original Message -----
> From: <elhardt@a...>
> To: <motm@y...>
> Sent: Sunday, November 03, 2002 1:58 AM
> Subject: [motm] transducers, input or output?
> 
> 
> > I've always thought that transducers were another name for
pickups, and
> doing
> > an internet search that seems to be what they are. They convert an
> acoustic
> > vibration into an electrical signal. But when reading about the
old Ondes
> > Martenot keyboard instrument, they say that one of the speakers (or
> diffusers)
> > uses a transducer to drive the strings on one of these diffusers.
Is there
> a
> > device that I can use that takes an electronic signal and converts
it into
> an
> > acoustic vibration for setting a string in motion or driving the
bridge of
> an
> > acoustic instrument? Something other than a speaker that is. I'm still
> thinking
> > about setting a violin in motion using a synthesizer.
> >
> > -Elhardt