MOTM

--- In motm@y..., elhardt@a... wrote:
> 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. [...]

By definition, a transducer is a device that converts energy from one 
form into another.  (So loudspeakers, microphones, light emitting 
diodes, photovoltaic cells, peltier junctions, all of these are 
transducers.)  Most transducers are also bi-directional, though they 
might be most effective in the intended forward conversion.  (Meaning, 
for example, that you can hook a loudspeaker up to the input of an 
amplifier and use it as a microphone of questionable fidelity.)


> [...] 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.

As to some "electrical" way of exciting a stringed instrument, it 
seems like part of the challenge is that you don't actually want to 
"touch" the strings, right?  Or rather, if the transducer were going 
to touch the string, you probably want to put it in place of the 
bridge (if the intent were to have the string resonate at its open 
tuning) or to touch at a specific location along the fret board (if 
the intent were to have the string resonate at a specific fretted 
note.)

If I were going to attempt this, I think the first thing I would try 
is a piezoelectric element.  Piezos are most often flat discs so you 
might glue a small wedge shaped block to one side of the disc and have 
the tip of this wedge touching the string in the intended location.


Seth