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Shattering Glasses?

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Anonymous
February 4, 2005 3:54:26 AM

Archived from groups: rec.audio.tech (More info?)

I'm designing a system for shattering wine glasses with high intensity
sound, but my design doesn't "feel" right to me, and I need somebody to
tell me if I've forgotten something important. I need an oscilloscope to
measure the resonant frequency of the glass and a frequency generator to
produce it. I need stereo speakers and a stereo amplifier powerful enough
to generate the sound to break the glass.

But how do I correctly get the signal from the frequency generator into the
stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?
If I need a pre-amp, how do I spec it, on the outputs of the freq generator
and the input of the amplifier? What if I'm using a receiver with the pre-
amplifier and the amplifier built-in? Can I just use the pre-amp that was
intended for the turntable?

More about : shattering glasses

Anonymous
February 4, 2005 3:54:27 AM

Archived from groups: rec.audio.tech (More info?)

Selecting the correct wine glass might be the most important item.

Rgds:
Eric

"John Schutkeker" <jschutkeker@sbcglobal.net.nospam> wrote in message
news:Xns95F2CA92BB760lkajehoriuasldfjknak@151.164.30.44...
>
> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody to
> tell me if I've forgotten something important. I need an oscilloscope to
> measure the resonant frequency of the glass and a frequency generator to
> produce it. I need stereo speakers and a stereo amplifier powerful enough
> to generate the sound to break the glass.
>
> But how do I correctly get the signal from the frequency generator into
the
> stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?
> If I need a pre-amp, how do I spec it, on the outputs of the freq
generator
> and the input of the amplifier? What if I'm using a receiver with the
pre-
> amplifier and the amplifier built-in? Can I just use the pre-amp that was
> intended for the turntable?
>
Anonymous
February 4, 2005 3:54:27 AM

Archived from groups: rec.audio.tech (More info?)

In article <Xns95F2CA92BB760lkajehoriuasldfjknak@151.164.30.44>,
John Schutkeker <jschutkeker@sbcglobal.net.nospam> wrote:

> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody to
> tell me if I've forgotten something important. I need an oscilloscope to
> measure the resonant frequency of the glass and a frequency generator to
> produce it. I need stereo speakers and a stereo amplifier powerful enough
> to generate the sound to break the glass.
>
> But how do I correctly get the signal from the frequency generator into the
> stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?
> If I need a pre-amp, how do I spec it, on the outputs of the freq generator
> and the input of the amplifier? What if I'm using a receiver with the pre-
> amplifier and the amplifier built-in? Can I just use the pre-amp that was
> intended for the turntable?

Most signal generators have a variable output. Set it to around 0.5 to
1.0 volts.

As others mentioned, breaking the glass could be difficult. You'll need
a glass with an extremely high Q; one that rings easily and loudly when
rubbed. You'll also need precision frequency tuning to resonate an
object with such a high Q. Most wine glasses won't break before your
ears do.
Related resources
Anonymous
February 4, 2005 10:58:48 AM

Archived from groups: rec.audio.tech (More info?)

John Schutkeker wrote:

> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody to
> tell me if I've forgotten something important. I need an oscilloscope to
> measure the resonant frequency of the glass and a frequency generator to
> produce it. I need stereo speakers and a stereo amplifier powerful enough
> to generate the sound to break the glass.
>
> But how do I correctly get the signal from the frequency generator into the
> stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?
> If I need a pre-amp, how do I spec it, on the outputs of the freq generator
> and the input of the amplifier? What if I'm using a receiver with the pre-
> amplifier and the amplifier built-in? Can I just use the pre-amp that was
> intended for the turntable?

You don't need a 'scope or a signal generator.
Stick a contact microphone on the glass base, plug it into a low-level
input on a guitar amp, turn it up to 11 and let feedback do its work.

You could rent a soprano for a couple of hours from your local
choral society.

http://www.worldofglass.com/exhibitions/news_item.asp?N...

--
Eiron.
Anonymous
February 4, 2005 10:58:49 AM

Archived from groups: rec.audio.tech (More info?)

In article <36go9rF4raanoU1@individual.net>, Eiron <e1ron@hotmail.com>
wrote:

> John Schutkeker wrote:
>
> > I'm designing a system for shattering wine glasses with high intensity
> > sound, but my design doesn't "feel" right to me, and I need somebody to
> > tell me if I've forgotten something important. I need an oscilloscope to
> > measure the resonant frequency of the glass and a frequency generator to
> > produce it. I need stereo speakers and a stereo amplifier powerful enough
> > to generate the sound to break the glass.
> >
> > But how do I correctly get the signal from the frequency generator into the
> > stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?
> > If I need a pre-amp, how do I spec it, on the outputs of the freq generator
> > and the input of the amplifier? What if I'm using a receiver with the pre-
> > amplifier and the amplifier built-in? Can I just use the pre-amp that was
> > intended for the turntable?
>
> You don't need a 'scope or a signal generator.
> Stick a contact microphone on the glass base, plug it into a low-level
> input on a guitar amp, turn it up to 11 and let feedback do its work.

I've tried that and it didn't work. The feedback loop finds many odd
local resonances based on them having much better phase alignment than
the primary resonance frequency. It would take a lot of fussing with
the microphone and speaker positions to make it work.

> You could rent a soprano for a couple of hours from your local
> choral society.
>
> http://www.worldofglass.com/exhibitions/news_item.asp?N...
Anonymous
February 4, 2005 11:01:48 AM

Archived from groups: rec.audio.tech (More info?)

"John Schutkeker" <jschutkeker@sbcglobal.net.nospam> wrote in message
news:Xns95F2CA92BB760lkajehoriuasldfjknak@151.164.30.44
> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody
> to tell me if I've forgotten something important. I need an
> oscilloscope to measure the resonant frequency of the glass and a
> frequency generator to produce it. I need stereo speakers and a
> stereo amplifier powerful enough to generate the sound to break the
> glass.
>
> But how do I correctly get the signal from the frequency generator
> into the stereo amplifier. Do I need a pre-amp, or do I just wire it
> straight in?

Just about any good signal generator has enough output to drive just about
any power amp to full power, and beyond.
February 4, 2005 11:24:21 AM

Archived from groups: rec.audio.tech (More info?)

In article <Xns95F2CA92BB760lkajehoriuasldfjknak@151.164.30.44>,
John Schutkeker <jschutkeker@sbcglobal.net.nospam> wrote:

> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody to
> tell me if I've forgotten something important. I need an oscilloscope to
> measure the resonant frequency of the glass and a frequency generator to
> produce it. I need stereo speakers and a stereo amplifier powerful enough
> to generate the sound to break the glass.
>

I see 2 ways to go about this-

1. Pick the wine glass, measure the resonant frequency as you described.
And design a high sensitivity/high spl/bandpassed speaker configuration
that best reproduces that frequency range.

2. Pick a high sensitivity/high spl/bandpassed speaker configuration and
find a wine glass that its resonant frequency falls into.

Either way its just a matter of time and money.

Why not just throw the wine glass? Whats the point of this show?

> But how do I correctly get the signal from the frequency generator into the
> stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?

Use the computer that sent this message, find a software frequency
generator, output a line level signal to a mixer/amp.

> If I need a pre-amp, how do I spec it, on the outputs of the freq generator
> and the input of the amplifier? What if I'm using a receiver with the pre-
> amplifier and the amplifier built-in?

I seriously doubt a receiver has enough wattage for something of this
nature, but anything can happen with the high sensitivity that a
correctly set up speaker configuration can provide.

> Can I just use the pre-amp that was
> intended for the turntable?
>

Phono inputs will have an RIAA eq curve.

--
Cyrus

*coughcasaucedoprodigynetcough*
Anonymous
February 4, 2005 11:42:19 AM

Archived from groups: rec.audio.tech (More info?)

Kevin McMurtrie wrote:

>>You don't need a 'scope or a signal generator.
>>Stick a contact microphone on the glass base, plug it into a low-level
>>input on a guitar amp, turn it up to 11 and let feedback do its work.
>
>
> I've tried that and it didn't work. The feedback loop finds many odd
> local resonances based on them having much better phase alignment than
> the primary resonance frequency. It would take a lot of fussing with
> the microphone and speaker positions to make it work.

In that case, plug the microphone into your computer.
Use a free frequency measurement program such as:
http://www.aptuner.com/cgi-bin/aptuner/apmain.html
to measure the resonant frequency of the glass when you tap it.

Then it is easy enough to generate a sinewave on the computer
and either cut a CD or plug the computer's line out into your amp.

--
Eiron.
Anonymous
February 4, 2005 3:11:48 PM

Archived from groups: rec.audio.tech (More info?)

"John Schutkeker" <jschutkeker@sbcglobal.net.nospam> wrote in message
news:Xns95F2CA92BB760lkajehoriuasldfjknak@151.164.30.44...
>
> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody to
> tell me if I've forgotten something important. I need an oscilloscope to
> measure the resonant frequency of the glass and a frequency generator to
> produce it. I need stereo speakers and a stereo amplifier powerful enough
> to generate the sound to break the glass.
>
> But how do I correctly get the signal from the frequency generator into
> the
> stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?
> If I need a pre-amp, how do I spec it, on the outputs of the freq
> generator
> and the input of the amplifier? What if I'm using a receiver with the
> pre-
> amplifier and the amplifier built-in? Can I just use the pre-amp that was
> intended for the turntable?

**You'll find that this task is not as easy as it seems. You'll probably
need a wine glass with a weakened structure and HUGE SPLs. Really HUGE SPLs.
The amplifier is the least of your concerns. I'd be searching for a speaker
with at least 100dB/W/M SPL capability.

I'm guessing you will want to measure the glass's resonant frequency and
drive the sig gen with that frequency. I don't know how you'll measure the
glass's resonant point, without altering. Schrödinger's Cat and all that.


--
Trevor Wilson
www.rageaudio.com.au
Anonymous
February 4, 2005 3:30:33 PM

Archived from groups: rec.audio.tech (More info?)

On Fri, 04 Feb 2005 00:54:26 GMT, John Schutkeker
<jschutkeker@sbcglobal.net.nospam> wrote:

>I'm designing a system for shattering wine glasses with high intensity
>sound, but my design doesn't "feel" right to me, and I need somebody to
>tell me if I've forgotten something important. I need an oscilloscope to
>measure the resonant frequency of the glass and a frequency generator to
>produce it. I need stereo speakers and a stereo amplifier powerful enough
>to generate the sound to break the glass.


Why do you need to know the numbers? Why does the amp/speakers need
to be stereo?

Set up your generator and sweep the frequency until the glass "rings"
and shatters. If it's going to - I think your main problem will be
finding suitable glasses.

If you want an idea what sort of frequency to start at, make the glass
"sing" by rubbing the rim. Use your ears to match the generator
frequency. Try simple multiples of that frequency too.
Anonymous
February 4, 2005 4:03:27 PM

Archived from groups: rec.audio.tech (More info?)

John Schutkeker wrote:
> I'm designing a system for shattering wine glasses with high intensity
> sound, but my design doesn't "feel" right to me, and I need somebody
> to tell me if I've forgotten something important. I need an
> oscilloscope to measure the resonant frequency of the glass and a
> frequency generator to produce it. I need stereo speakers and a
> stereo amplifier powerful enough to generate the sound to break the
> glass.
>
> But how do I correctly get the signal from the frequency generator
> into the stereo amplifier. Do I need a pre-amp, or do I just wire it
> straight in? If I need a pre-amp, how do I spec it, on the outputs of
> the freq generator and the input of the amplifier? What if I'm using
> a receiver with the pre- amplifier and the amplifier built-in? Can I
> just use the pre-amp that was intended for the turntable?

They did this on an episode of 'Mythbusters' on Discovery (I think). Using
an opera singer and a metal rocker, they had each tap the glass for tone.
They put it in front of a small p.a. speaker and had the vocalist sing the
note they heard when they tapped the glass. IIRC, they also put a straw in
the glass as an indicator of when it was nearing resonance.

The hard rocker was able to get the glass to shatter, but the opera singer
was not....

jak
Anonymous
February 5, 2005 5:22:51 PM

Archived from groups: rec.audio.tech (More info?)

>
>
>I'm designing a system for shattering wine glasses with high intensity
>sound, but my design doesn't "feel" right to me, and I need somebody to
>tell me if I've forgotten something important. I need an oscilloscope to
>measure the resonant frequency of the glass and a frequency generator to
>produce it. I need stereo speakers and a stereo amplifier powerful enough
>to generate the sound to break the glass.
>
>But how do I correctly get the signal from the frequency generator into the
>stereo amplifier. Do I need a pre-amp, or do I just wire it straight in?

Most frequency generators that I have used have variable output, so all you
need to do is run it straight into the amplifier.



>If I need a pre-amp, how do I spec it, on the outputs of the freq generator
>and the input of the amplifier?

You need both specs in order for it to work correctly.

If your Frequency Generator is a -10dBV device(316mV) and your amplifier wants
to see +4dBu (1.23V) , you will need a voltage gain of 11.8 dB to match them.

Conversely If your frequency generator puts out +4dBu and your amplifier is
consmer stuff at -10dBV, youwill neet a 11.8dB attenuator to match.

What if I'm using a receiver with the pre-
>amplifier and the amplifier built-in? Can I just use the pre-amp that was
>intended for the turntable?

No.
The preamp for the turntable has an extreme EQ curve built into it. it will
boost the bottom end by 20 dB and cut the highs by a similar amount. Basically,
it won't work correctly.
>
>
>

Your biggest problem is going to be able to find HFspeakers that can handle
high power. You may fry a few before you complete this experiment.


Richard H. Kuschel
"I canna change the law of physics."-----Scotty
!