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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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 Posted: Sun Jul 02, 2006 2:22 pm Post subject:
5 gallon musical water bottle
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I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
Any pointers will be appreciated.
Glenn |
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Mike Amling
science forum Guru
Joined: 05 May 2005
Posts: 525
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| Posted: Sun Jul 02, 2006 2:32 pm Post subject:
Re: 5 gallon musical water bottle
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On Sun, 02 Jul 2006 09:22:07 -0500, Glenn Sowell <sowell2@cox.net>
wrote:
| Quote: | I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
Any pointers will be appreciated.
Glenn
|
You can't. And why would you want to? All of the quality of the sound
lies in those overtones. If you excited just the fundamentals you
would have sine waves, and not only are they very unmusical, but there
are much easier ways to make them then by blowing over bottles.
Having said all that, those plastic bottles aren't very stiff - they
vibrate strongly when you excite them that way and that absorbs much
of the sound energy. If you could get hold of stiffer bottles, like
the carboys that liquid chemicals come in, you would be able to
deliver a much more powerful sound.
d
--
Pearce Consulting
http://www.pearce.uk.com |
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woinem1@aol.com
science forum beginner
Joined: 03 Jul 2006
Posts: 6
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| Posted: Mon Jul 03, 2006 1:49 pm Post subject:
Re: 5 gallon musical water bottle
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Don Pearce schrieb:
| Quote: | On Sun, 02 Jul 2006 09:22:07 -0500, Glenn Sowell <sowell2@cox.net
wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
Any pointers will be appreciated.
Glenn
You can't. And why would you want to? All of the quality of the sound
lies in those overtones. If you excited just the fundamentals you
would have sine waves, and not only are they very unmusical, but there
are much easier ways to make them then by blowing over bottles.
Having said all that, those plastic bottles aren't very stiff - they
vibrate strongly when you excite them that way and that absorbs much
of the sound energy. If you could get hold of stiffer bottles, like
the carboys that liquid chemicals come in, you would be able to
deliver a much more powerful sound.
d
--
Pearce Consulting
http://www.pearce.uk.com |
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woinem1@aol.com
science forum beginner
Joined: 03 Jul 2006
Posts: 6
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| Posted: Mon Jul 03, 2006 1:52 pm Post subject:
Re: 5 gallon musical water bottle
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Don Pearce schrieb:
| Quote: | On Sun, 02 Jul 2006 09:22:07 -0500, Glenn Sowell <sowell2@cox.net
wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
You might find some answers here: |
http://members.aol.com/woinem1/index/physik.htm
and
http://perso.nnx.com/dferment/ukplasto.htm
We play with winddriven instruments since years now.
Have fun
Uli |
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ari
science forum beginner
Joined: 11 Jul 2005
Posts: 9
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| Posted: Mon Jul 03, 2006 4:38 pm Post subject:
Re: 5 gallon musical water bottle
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First guess is, that it is the case of laminar-turbulent transition.
So i have to agree with Don on the overtones. It is, most probably, the
lowest or second lowest mode of the system that is the loudest tone.
The flow velocity (or in more detail boundary layer on the leading edge
of "the hole") effects the flow-acoustics coupling in the systems
(possibly both Helmholz and organ pipes modes can be found). Further
more, the vibrating bottle surface can affect the feedback and it is
possible that it increases the sound.
Something similar happens also in turbulent flow.
And "pointers". Especially for laminar turbulent transition see
perturbation theory. To my knowledge Michalke A.´s version is most
complete (more complete than commonly found in Fluid dynamics books).
For practical purposes, i suggest that you start with Rockwell D.,
Naudascher E., Review – Selfsustaining oscillations of flow past
cavities, Journal of Fluids Engineering, vol 100 (June 1978), ss.
152-165. In acoustics analogies Howe M. S. and Doak P. E. (separately)
have dealt with similar cases.
hope this helps
ari
machineryacoustics.fi
Don Pearce wrote:
| Quote: | On Sun, 02 Jul 2006 09:22:07 -0500, Glenn Sowell <sowell2@cox.net
wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
Any pointers will be appreciated.
Glenn
You can't. And why would you want to? All of the quality of the sound
lies in those overtones. If you excited just the fundamentals you
would have sine waves, and not only are they very unmusical, but there
are much easier ways to make them then by blowing over bottles.
Having said all that, those plastic bottles aren't very stiff - they
vibrate strongly when you excite them that way and that absorbs much
of the sound energy. If you could get hold of stiffer bottles, like
the carboys that liquid chemicals come in, you would be able to
deliver a much more powerful sound.
d
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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| Posted: Tue Jul 04, 2006 12:08 pm Post subject:
Re: 5 gallon musical water bottle
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In article <44a8d82b.15035921@text.usenet.plus.net>, Don Pearce
<nospam@nospam.com> wrote:
| Quote: | On Sun, 02 Jul 2006 09:22:07 -0500, Glenn Sowell <sowell2@cox.net
wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
Any pointers will be appreciated.
Glenn
You can't. And why would you want to? All of the quality of the sound
lies in those overtones. If you excited just the fundamentals you
would have sine waves, and not only are they very unmusical, but there
are much easier ways to make them then by blowing over bottles.
Having said all that, those plastic bottles aren't very stiff - they
vibrate strongly when you excite them that way and that absorbs much
of the sound energy. If you could get hold of stiffer bottles, like
the carboys that liquid chemicals come in, you would be able to
deliver a much more powerful sound.
d
You are right, of course. But the notes are accompained by high-pitched |
squeals. Those I don't want.
The plastic bottles do vibrate strongly, but that does not stop 2-liter
pop bottles from working nicely.
Thanks
Glenn |
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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| Posted: Tue Jul 04, 2006 12:10 pm Post subject:
Re: 5 gallon musical water bottle
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The wind driven instruments look very interesting. Thanks for the links.
Glenn
In article <1151934758.227415.57340@h44g2000cwa.googlegroups.com>,
<woinem1@aol.com> wrote:
| Quote: | Don Pearce schrieb:
On Sun, 02 Jul 2006 09:22:07 -0500, Glenn Sowell <sowell2@cox.net
wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
I can excite a REALLY low note by blowing air from a vacuum cleaner
across the top. Unfortunately, I also excite several overtones as well.
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
You might find some answers here:
http://members.aol.com/woinem1/index/physik.htm
and
http://perso.nnx.com/dferment/ukplasto.htm
We play with winddriven instruments since years now.
Have fun
Uli
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Mike Amling
science forum Guru
Joined: 05 May 2005
Posts: 525
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| Posted: Tue Jul 04, 2006 12:11 pm Post subject:
Re: 5 gallon musical water bottle
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On Tue, 04 Jul 2006 07:08:36 -0500, Glenn Sowell <sowell2@cox.net>
wrote:
| Quote: | You are right, of course. But the notes are accompained by high-pitched
squeals. Those I don't want.
The plastic bottles do vibrate strongly, but that does not stop 2-liter
pop bottles from working nicely.
Thanks
Glenn
|
Huh? High pitched squeals are what makes it all worthwhile! That's
only one step short of throwing knickers.
Have you tries varying the angle of incidence of the air blast? You
should be able to kill them.
d
--
Pearce Consulting
http://www.pearce.uk.com |
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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| Posted: Tue Jul 04, 2006 1:32 pm Post subject:
Re: 5 gallon musical water bottle
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Yeah, I tried varing the angles. Mind you, I am using a vacuum cleaner
hose which has a circular opening about 2 cm in diameter. Would a flat,
narrower opening work better? I've got that attachment too!
Glenn
In article <44aa5a87.179479656@text.usenet.plus.net>, Don Pearce
<nospam@nospam.com> wrote:
| Quote: | On Tue, 04 Jul 2006 07:08:36 -0500, Glenn Sowell <sowell2@cox.net
wrote:
You are right, of course. But the notes are accompained by high-pitched
squeals. Those I don't want.
The plastic bottles do vibrate strongly, but that does not stop 2-liter
pop bottles from working nicely.
Thanks
Glenn
Huh? High pitched squeals are what makes it all worthwhile! That's
only one step short of throwing knickers.
Have you tries varying the angle of incidence of the air blast? You
should be able to kill them.
d |
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Mike Amling
science forum Guru
Joined: 05 May 2005
Posts: 525
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| Posted: Tue Jul 04, 2006 1:36 pm Post subject:
Re: 5 gallon musical water bottle
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On Tue, 04 Jul 2006 08:32:38 -0500, Glenn Sowell <sowell2@cox.net>
wrote:
| Quote: | Yeah, I tried varing the angles. Mind you, I am using a vacuum cleaner
hose which has a circular opening about 2 cm in diameter. Would a flat,
narrower opening work better? I've got that attachment too!
Glenn
|
I think there is a very good chance you are overblowing the bottle - a
vacuum cleaner expels quite a quantity of air. Any way you could
reduce the flow rate?
d
--
Pearce Consulting
http://www.pearce.uk.com |
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ari
science forum beginner
Joined: 11 Jul 2005
Posts: 9
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| Posted: Tue Jul 04, 2006 1:55 pm Post subject:
Re: 5 gallon musical water bottle
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Don Pearce wrote:
| Quote: | On Tue, 04 Jul 2006 08:32:38 -0500, Glenn Sowell <sowell2@cox.net
wrote:
Yeah, I tried varing the angles. Mind you, I am using a vacuum cleaner
hose which has a circular opening about 2 cm in diameter. Would a flat,
narrower opening work better? I've got that attachment too!
Glenn
I think there is a very good chance you are overblowing the bottle - a
vacuum cleaner expels quite a quantity of air. Any way you could
reduce the flow rate?
How about increasing pressure drop over the fan, for example by blocking |
the flow into the cleaner. Or taking a vacuum cleaner with a suction
control.
The angles, opening shapes, out flow velocities etc. things that modify
the incoming boundary layer might work. The same should/could apply with
the trailing edge of the opening (effects the feedback).
It might be worthwhile to remember that from physical point of view this
is not an easy thing to evaluate/estimate/forecast.
ari
machineryacoustics.fi |
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woinem1@aol.com
science forum beginner
Joined: 03 Jul 2006
Posts: 6
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| Posted: Tue Jul 04, 2006 2:23 pm Post subject:
Re: 5 gallon musical water bottle
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Glenn Sowell schrieb:
| Quote: | I can excite a REALLY low note by blowing air from a vacuum cleaner
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Hi Glenn,
do you have a recording of those sounds? I think it would be easier to
find the reason for those high pitches if I could put "an ear into
it"...
Uli Wahl
http://members.aol.com/woinem1/index/ |
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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| Posted: Tue Jul 04, 2006 3:32 pm Post subject:
Re: 5 gallon musical water bottle
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Both Ari and Don have good suggestions, which I will try tomorrow
(Wednesday). Today is a holiday in the US and my water bottles are at
work!
Thanks
Glenn
In article <fsuqg.13989$uQ5.10877@reader1.news.jippii.net>, ari
<ari.karjalainen@NOSPAMnic.fi> wrote:
| Quote: | Don Pearce wrote:
On Tue, 04 Jul 2006 08:32:38 -0500, Glenn Sowell <sowell2@cox.net
wrote:
Yeah, I tried varing the angles. Mind you, I am using a vacuum cleaner
hose which has a circular opening about 2 cm in diameter. Would a flat,
narrower opening work better? I've got that attachment too!
Glenn
I think there is a very good chance you are overblowing the bottle - a
vacuum cleaner expels quite a quantity of air. Any way you could
reduce the flow rate?
How about increasing pressure drop over the fan, for example by blocking
the flow into the cleaner. Or taking a vacuum cleaner with a suction
control.
The angles, opening shapes, out flow velocities etc. things that modify
the incoming boundary layer might work. The same should/could apply with
the trailing edge of the opening (effects the feedback).
It might be worthwhile to remember that from physical point of view this
is not an easy thing to evaluate/estimate/forecast.
ari
machineryacoustics.fi |
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| Back to top |
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Greg Locock
science forum Guru Wannabe
Joined: 28 May 2005
Posts: 111
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| Posted: Wed Jul 05, 2006 12:15 pm Post subject:
Re: 5 gallon musical water bottle
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woinem1@aol.com wrote in news:1152022998.895410.47520
@v61g2000cwv.googlegroups.com:
| Quote: |
Glenn Sowell schrieb:
I can excite a REALLY low note by blowing air from a vacuum cleaner
|
| Quote: | do you have a recording of those sounds? I think it would be easier to
find the reason for those high pitches if I could put "an ear into
it"...
|
Let me guess, third fifth and so on harmonics.
What will you learn?
Cheers
Greg |
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woinem1@aol.com
science forum beginner
Joined: 03 Jul 2006
Posts: 6
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| Posted: Wed Jul 05, 2006 3:00 pm Post subject:
Re: 5 gallon musical water bottle
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Greg Locock schrieb:
| Quote: | Let me guess, third fifth and so on harmonics.
What will you learn?
I'd like to know more about the nature of those high pitches. |
Are they generated at the soundhole? Then you're right with the
harmonics.
Are they generated by vibrations/ fluttering of the walls ofd the
bottle (depending where the soundhole has been placed.
Are they generated by the corrugated tube of the vacuum cleaner?
All this my ears wants to learn by the recording...  )
Jam and troast
Uli |
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