MOTM

> 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. [...]

> [...] 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.

> 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.

>>Or rather, if the transducer were going to touch the string, you probably

>>If I were going to attempt this, I think the first thing I would try

>>You mean something like this?

> In a message dated 03 Nov 2002 06:58:57 +0000, elhardt@a... writes:
>
> > 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.
>
> You mean something like this?
>
> http://www.ebow.com/

----- Original Message -----
From: <elhardt@...>
I was asking about vibrating a string mostly out of curiousity for other
things I had in mind. But what I would really want to do now is remove the
lowest sounding string on something like a violin and put a device on the
bridge in its place that will vibrate the bridge which in turn puts the
whole violin body into motion. I would probably just use a sawtooth wave
and would control the pitch from a synthesizer.

--LH--
The whole problem with this as I see it is the notion that the pitch could
be altered by changing the frequency of the device inducing the string to
vibrate. The string has a natural frequency at which it will resonate
(along with many associated harmonics). The only way to change that
frequency is to adjust the tension of the string or adjust the length (by
fretting).

Assuming that one used a variable frequency and was successful at getting a
string to vibrate, I would think that only amplitude, and not frequency
would vary. As the frequency of the modulating signal approached the
resonate frequency of the string, vibration would be at maximum amplitude.
As frequency increase or decreased from that point, the sting would simply
become less responsive to the inducing device.

That's how I see it. And, I would think that only low frequencies could be
induced to begin with. And, then, it seems an electro-mechanical induction
might produce the best response from the string. So, metal would work (like
it does with the guitar e-bow thing). But, I would think non-metallic
strings would be very resistance to significant induced vibration. Perhaps
acoustically induced. But, I am guessing the amplitude of the signal needed
to induce the string to vibrate would mask the actual sound of the vibrating
string.

However, I have seen all strings of a piano set into simultaneous vibration
by musicians mixing drinking and equipment moving. As my memory serves me
(and it seems a bit cloudy on the event), I think each string vibrated at
its own tuned frequency.

Well, that's my $.02 on the subject. I do know a "little bit" about low
frequency induction issues. Say, around 60 Hz.
<snicker>

Larry (the power) Stooge

--- 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. 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

--- In motm@y..., "sucrosemusic" <sucrosemusic@y...> wrote:
> OK, I don't know what violin strings are made of, BUT if they're
> ferrous, I'd wire up an electromagnet, just a coil of some sort,
and
> put in in the 'sweet spot' on the strings where either of the
pickups
> on an electric guitar are placed. Placing it at different position
> will affect the sound, because certain harmonics will be easier to
> get into motion in certain spots.
>
> Find out if you can get violin strings that are ferrous, though.
> That's the key. Also, you're going to probably need to amplify
your
> signal quite a bit before your electromagnet will wiggle the
strings
> noticably (estimate around 20 watts, but who knows) since you're
> basically making a speaker, but without a cone... or a permanent
> magnet... etc etc. It'll be weak. It'll work. It won't work
with
> nylon strings.
>
>
> --- 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. 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

--- In motm@y..., "Michel Havenith" <anymail@x> wrote:
> The E string of a modern violin is usually made of steel or a steel
> with gold alloy. I checked with my violin and the E string reacted
on
> a magnet. Buy a cheap string, they have the most amount of steel!
>
> Michel Havenith,
> Netherlands
>
>
> --- In motm@y..., "sucrosemusic" <sucrosemusic@y...> wrote:
> > OK, I don't know what violin strings are made of, BUT if they're
> > ferrous, I'd wire up an electromagnet, just a coil of some sort,
> and
> > put in in the 'sweet spot' on the strings where either of the
> pickups
> > on an electric guitar are placed. Placing it at different
position
> > will affect the sound, because certain harmonics will be easier
to
> > get into motion in certain spots.
> >
> > Find out if you can get violin strings that are ferrous, though.
> > That's the key. Also, you're going to probably need to amplify
> your
> > signal quite a bit before your electromagnet will wiggle the
> strings
> > noticably (estimate around 20 watts, but who knows) since you're
> > basically making a speaker, but without a cone... or a permanent
> > magnet... etc etc. It'll be weak. It'll work. It won't work
> with
> > nylon strings.
> >
> >
> > --- 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. 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

----- Original Message -----
From: <elhardt@...>
To: <motm@yahoogroups.com>
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

--- 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

> I was asking about vibrating a string mostly out of
> curiousity for other things
> I had in mind. But what I would really want to do
> now is remove the lowest
> sounding string on something like a violin and put a
> device on the bridge in
> its place that will vibrate the bridge which in turn
> puts the whole violin body
> into motion.

>>As usual, I have made a total Stooge of myself.<<

>>To rectify my error, I will report to you that All Electronics has a

----- Original Message -----
From: <elhardt@...>
Larry Hendry missed the part where I said I wanted to remove a string and in
its place put some kind of device to vibrate the bridge. That would vibrate
at whatever pitch my synthesized waveform is. So matt_stubb and groovshaman
are correct in understanding what I wanted to do.

> I won't copy and paste everybodies posts to keep from making a

> respond. Larry Hendrey missed the part where I said I wanted to

> and in its place put some kind of device to vibrate the bridge.

> vibrate at whatever pitch my synthesized waveform is. So matt_stubb

> groovshaman are correct in understanding what I wanted to do. I

> keep the other 3 strings there to firmly hold the bridge down, plus

> reading I've been doing about the violin, the body tone is a little

> when under the tension of all the strings than without any strings.

> strings the main formants are lower in pitch.