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[motm] Re: transducers (piezo buzzer)

2002-11-05 by elhardt@att.net

Mike Marsh writes:

>>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...<<

I'm assuming that it is an acoustic guitar, and you will try to use the guitar
body to amplify the piezo sound. If so, I'd like to hear an mpeg if you record
one. I seem to remember the piezo buzzer I used ages ago only put out one tone.
I'm guessing your modification gets around that problem.

-Elhardt

Re: transducers (piezo buzzer)

2002-11-05 by Mike Marsh

I didn't get home 'till late last night so I couldn't try. Tonight,
though, I promise...

The piezo acts like a pick-up when attached to the bridge of a guitar.
The mod is simply soldering a cable to it with a jack. Sometimes I
cut the it into a different shape (it's normally) or just to get it
less hot. The output is amazingly loud.

The idea, I guess, is instead of having it translate vibration into
electrons (as it does when it's a pick-up), but to translate electrons
(from the MOTM) into vibration that will move the top of the guitar
through the bridge. Then mic the top to record.

Mike

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--- In motm@y..., elhardt@a... wrote:
> Mike Marsh writes:
> >>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...<<
>
> I'm assuming that it is an acoustic guitar, and you will try to use
the guitar
> body to amplify the piezo sound. If so, I'd like to hear an mpeg if
you record
> one. I seem to remember the piezo buzzer I used ages ago only put
out one tone.
> I'm guessing your modification gets around that problem.
>
> -Elhardt

[motm] Re: transducers (piezo buzzer)

2002-11-05 by elhardt@att.net

Mike Marsh writes:

>>The idea, I guess, is instead of having it translate vibration into

electrons (as it does when it's a pick-up), but to translate electrons
(from the MOTM) into vibration that will move the top of the guitar
through the bridge. Then mic the top to record.<<

That's correct. In using a guitar instead of a violin, perhaps you want to use
a synthesized percussive sound immitating a string pluck.

Tim Walters writes:

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>>David Tudor's "Rainforest" might have some ideas you could use. This piece

was created by attaching transducers to various resonant objects and
playing electronic tones through them.<<

Thanks for the info. It sounds like he is mechanically doing the same thing I
want to. I think the device Larry Hendry pointed out is what's needed for this
type of stuff.

-Elhardt

Re: [motm] Re: transducers (piezo buzzer)

2002-11-05 by Paul Schreiber

((solder break...received '600 uSeq proto boards today!))

I think this is going about it the wrong way.

More complicated, but more controllable is to get a mechanism to "push & pull" the bow across a
string. Not a regular bow, a small one (say 4 inches). I would do this:

a) get surplus stepper motor for $7
b) get sample of stepper motor driver IC (www.microlinear.com), TI has them, etc.
c) use $5 PIC to drive IC
d) use on-chip ADC of the PIC to have 2 inputs: speed and depth (like an LFO)

This is a simple setup: 2 ICs and a <100 line program

Paul S.

[motm] Re: transducers (piezo buzzer)

2002-11-05 by elhardt@att.net

Paul Schreiber writes:

>>I think this is going about it the wrong way. More complicated, but more

controllable is to get a mechanism to "push & pull" the bow across a string.
Not a regular bow, a small one (say 4 inches). I would do this:....<<

Maybe you haven't been following the posts too closely. We don't want to move
strings since the pitch can't be changed without a lot of other hardware. What
we want is the synthesizer to freely generate the pitches and a resonant
acoustic body to give it the character needed. Using a $9 transducer like LH
pointed out should hopefully be all that's needed besides a mic to record the
sound back into electronic form. If that fails, then that's where I stop
because I will have answered my question as to whether it can be done or not.

-Elhardt

Re: [motm] Re: transducers (piezo buzzer)

2002-11-05 by groovyshaman@snet.net

<elhardt@...> wrote:

> What we want is the synthesizer to freely generate the pitches and a

resonant

> acoustic body to give it the character needed. Using a $9 transducer like

> pointed out should hopefully be all that's needed besides a mic to record

the

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> sound back into electronic form. If that fails, then that's where I stop
> because I will have answered my question as to whether it can be done or

not.

Where there's a will, there's a way!

I have given some thought in the past about doing basically the same thing
with a cello body. The experiments I have done (along with a cellist friend
of mine) are primarally only half of what you are aiming to accomplish,
namely, signal pickup (via piezo) although I am hoping to at some point add
transducer stimulation of the bridge. Our plan was to mount the cello to a
"holder" (which we would have to design & build), attach a metal plate to
the cello's bridge, and mount an electromagnet to the holder within
proximity to the bridge. An amp module would have to be created that would
take as input a MOTM signal and output an appropriate level current to the
electromagnet, with voltage control over the "drive" of the current.

One thing we did verify is how markedly different the signal response is
based on the mounting location of the piezo pickup - no shock there. One
solution I had envisioned was to mount multiple piezos around the bridge,
body and neck of the cello, amplify them separately and mix them using
multiple MOTM VCAs, thereby allowing for different timbres to be selected
under voltage control. Never got around to that, unfortunately.

Cheers,
George

Re: transducers (piezo buzzer)

2002-11-06 by Mike Marsh

And to expand on this idea a little further: I plan to tune the
strings on the guitar to an open tuning (say, Open D) and then play a
sequence in the same key through the thing. I think the acoustic
drone of the strings will add (if I can believe what I'm hearing in my
head) and incredibly interesting background. I just hope the strings
don't overwhelm the sound from the synth, but we'll see...

Mike

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--- In motm@y..., elhardt@a... wrote:
> Paul Schreiber writes:
> >>I think this is going about it the wrong way. More complicated,
but more
> controllable is to get a mechanism to "push & pull" the bow across a
string.
> Not a regular bow, a small one (say 4 inches). I would do this:....<<
>
> Maybe you haven't been following the posts too closely. We don't
want to move
> strings since the pitch can't be changed without a lot of other
hardware. What
> we want is the synthesizer to freely generate the pitches and a
resonant
> acoustic body to give it the character needed. Using a $9 transducer
like LH
> pointed out should hopefully be all that's needed besides a mic to
record the
> sound back into electronic form. If that fails, then that's where I
stop
> because I will have answered my question as to whether it can be
done or not.
>
> -Elhardt