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| Author |
Message |
Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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 Posted: Fri Jul 07, 2006 12:40 am Post subject:
Re: 5 gallon musical water bottle
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They are generated at the sound hole.
Glenn
In article <1152111623.160600.323940@m79g2000cwm.googlegroups.com>,
<woinem1@aol.com> wrote:
| Quote: | Greg Locock schrieb:
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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Angelo Campanella
science forum Guru Wannabe
Joined: 08 May 2005
Posts: 226
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| Posted: Sat Jul 08, 2006 2:42 pm Post subject:
Re: 5 gallon musical water bottle
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|
Glenn Sowell wrote:
| Quote: | I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
|
That seems feasible.. filling any of them to various levels should
produce varios notes as desired.
| Quote: | 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.
|
My recollection of glass 5 gallon jugs is that the empty tone is about
30 or 60 Hz. One can ecite that tone by blowing one's breath across the
open mouth of the bottle. Wine bottle (750 ml) produce about 120 Hz.
The Helmholtz frequency calculations work well for approximate
prediction of the resulting tone.
But two perturbations arise that affect tone quality:
1- The Helmholtz calculation is accurate only for sound of wavelengths
very long as compared to the length of the bottle.
2- The turbulent nature of the flow of an aistream across the opening of
the bottle produces excitation over a wide range of audio frequencies.
Sound Eigenmodes of the bottle volume of wavelengths comparable to the
dimensions of that bottle will also be excited. Prediction of the
precise eigenmode frequencies cannot be done with the Helmholtz
calculation; rather it requires the cylindrical room method, treated at
least by Morse in "Vibration and sound".
| Quote: | How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
|
Bottle modes are excited by the turbulent velocity component along the
axis of the bottle opening centerline. The usual excitation is via the
(Von Karman) vortex street caused by the airflow over the edge of the
opening; trailing from first edge encountered by the airflow. The
frequency of that series of eddies depends on the flow velocity and
perhaps the diameter of the airstream.
Where the Helmholtz eigenmode is available, it soon becomes excited and
consequently controls the frequency of the vortex shedding rate. But it
is possible to blow with such a high velocity that higher frequency
eigenmodes that also exist for that cylindrical volume are also excited.
The mode of strongest excitation, or highest "Q" will likely dominate in
turn and control the edge vortex shedding rate for that flow condition.
I would think that the parameters that are controllable and privvy to
adjustment and selection are: Flow speed, Flow diameter, Edge sharpness
and flow incidence angle to that nearer edge.
It is all amenable to trial and error; and amenable to clever invention.
Good luck!
Angelo Campanella |
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Angelo Campanella
science forum Guru Wannabe
Joined: 08 May 2005
Posts: 226
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| Posted: Sat Jul 08, 2006 2:48 pm Post subject:
Re: 5 gallon musical water bottle
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Don Pearce wrote:
| Quote: | 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.
|
Agreed.
Old experiences are with glass bottles of relatively high rigidity. The
modern plastic bottle are much less rigid, and will generally produce
lower tones. I should expect that when partly filled with water, their
tones will change and rise more rapidly. Much more trial and error is
required to achieve a useful musical scale capability...
Angelo Campanella
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woinem1@aol.com
science forum beginner
Joined: 03 Jul 2006
Posts: 6
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| Posted: Sat Jul 08, 2006 7:26 pm Post subject:
Re: 5 gallon musical water bottle
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| Quote: | Old experiences are with glass bottles of relatively high rigidity. The
modern plastic bottle are much less rigid, and will generally produce
lower tones.
|
The problem are mainly square shaped bottles or bottles with flat
bottoms. The round bottles are no poblem in general, because its walls
don't vibrate. It is even possible to make (natural wind driven)
cylindrical organ pipes of 3-4 layers of glued paper without loss of
sound quality in comparison with metal ones.
So, one possibility to improve the sound would be to use bottles with a
cylindrical shape and to insert a rigid (or curved) bottom. A
possibility to make the sound louder would be to cout the soundhole
into the side wall of the cylindrical bottle. The length depending on
the thickness/ rigidity of the wall material. With plastic bottles,
there is in general a limit of soundhole-length. Otherwise the edges of
the soundhole begin to flutter and change the (desired?) sound...
Uli Wahl |
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Angelo Campanella
science forum Guru Wannabe
Joined: 08 May 2005
Posts: 226
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| Posted: Sun Jul 09, 2006 6:24 am Post subject:
Re: 5 gallon musical water bottle
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woinem1@aol.com wrote:
| Quote: | The problem are mainly square shaped bottles or bottles with flat
bottoms. The round bottles are no poblem in general, because its walls
don't vibrate. It is even possible to make (natural wind driven)
cylindrical organ pipes of 3-4 layers of glued paper without loss of
sound quality in comparison with metal ones.
|
Bottles of that type will also act as a drum when struck with the
fingers or a stick... an entirely different modus operandi.
| Quote: | So, one possibility to improve the sound would be to use bottles with a
cylindrical shape and to insert a rigid (or curved) bottom.
|
This wooud avoid the flexibele sidewall problem, but produce yet another
class of instrument, something like a wind pipe set.
| Quote: | A possibility to make the sound louder would be to cout the soundhole
into the side wall of the cylindrical bottle.
|
The hole will change the pitch.
| Quote: | The length depending on
the thickness/ rigidity of the wall material. With plastic bottles,
there is in general a limit of soundhole-length. Otherwise the edges of
the soundhole begin to flutter and change the (desired?) sound...
|
More invention required.
Angelo Campanella |
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woinem1@aol.com
science forum beginner
Joined: 03 Jul 2006
Posts: 6
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| Posted: Sun Jul 09, 2006 10:06 am Post subject:
Re: 5 gallon musical water bottle
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Angelo Campanella schrieb:
| Quote: | This would avoid the flexibele sidewall problem, but produce yet another
class of instrument, something like a wind pipe set.
The hole will change the pitch.
More invention required.
|
I agree.
Anyone else here having experiences in working with plastic bottles?
Uli Wahl |
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
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| Posted: Sun Jul 09, 2006 1:38 pm Post subject:
Re: 5 gallon musical water bottle
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|
In article <MvPrg.107079$mF2.49501@bgtnsc04-news.ops.worldnet.att.net>,
Angelo Campanella <a.campanella@att.net> wrote:
| Quote: | Glenn Sowell wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
That seems feasible.. filling any of them to various levels should
produce varios notes as desired.
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.
My recollection of glass 5 gallon jugs is that the empty tone is about
30 or 60 Hz. One can ecite that tone by blowing one's breath across the
open mouth of the bottle. Wine bottle (750 ml) produce about 120 Hz.
|
You must have a bigger lung capacity than I do!! I have been unable to
produce a sustained note simply by blowing. The opening to the bottle
is about 5 cm diameter.
| Quote: | The Helmholtz frequency calculations work well for approximate
prediction of the resulting tone.
But two perturbations arise that affect tone quality:
1- The Helmholtz calculation is accurate only for sound of wavelengths
very long as compared to the length of the bottle.
2- The turbulent nature of the flow of an aistream across the opening of
the bottle produces excitation over a wide range of audio frequencies.
Sound Eigenmodes of the bottle volume of wavelengths comparable to the
dimensions of that bottle will also be excited. Prediction of the
precise eigenmode frequencies cannot be done with the Helmholtz
calculation; rather it requires the cylindrical room method, treated at
least by Morse in "Vibration and sound".
How can I excite just the fundamental? Slower moving air? By shaping
the vacuum attachment through which is blown?
Bottle modes are excited by the turbulent velocity component along the
axis of the bottle opening centerline. The usual excitation is via the
(Von Karman) vortex street caused by the airflow over the edge of the
opening; trailing from first edge encountered by the airflow. The
frequency of that series of eddies depends on the flow velocity and
perhaps the diameter of the airstream.
Where the Helmholtz eigenmode is available, it soon becomes excited and
consequently controls the frequency of the vortex shedding rate. But it
is possible to blow with such a high velocity that higher frequency
eigenmodes that also exist for that cylindrical volume are also excited.
The mode of strongest excitation, or highest "Q" will likely dominate in
turn and control the edge vortex shedding rate for that flow condition.
I would think that the parameters that are controllable and privvy to
adjustment and selection are: Flow speed, Flow diameter, Edge sharpness
and flow incidence angle to that nearer edge.
It is all amenable to trial and error; and amenable to clever invention.
Good luck!
Angelo Campanella
|
Thanks
Glenn
> |
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
|
| Posted: Sun Jul 09, 2006 1:40 pm Post subject:
Re: 5 gallon musical water bottle
|
|
|
In article <1152386800.766499.135000@p79g2000cwp.googlegroups.com>,
<woinem1@aol.com> wrote:
| Quote: | Old experiences are with glass bottles of relatively high rigidity. The
modern plastic bottle are much less rigid, and will generally produce
lower tones.
The problem are mainly square shaped bottles or bottles with flat
bottoms. The round bottles are no poblem in general, because its walls
don't vibrate. It is even possible to make (natural wind driven)
cylindrical organ pipes of 3-4 layers of glued paper without loss of
sound quality in comparison with metal ones.
So, one possibility to improve the sound would be to use bottles with a
cylindrical shape and to insert a rigid (or curved) bottom. A
possibility to make the sound louder would be to cout the soundhole
into the side wall of the cylindrical bottle. The length depending on
the thickness/ rigidity of the wall material. With plastic bottles,
there is in general a limit of soundhole-length. Otherwise the edges of
the soundhole begin to flutter and change the (desired?) sound...
Uli Wahl
|
My bottles are cylindrical on the sides. The bottom is approximately
flat.
Thanks
Glenn |
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Angelo Campanella
science forum Guru Wannabe
Joined: 08 May 2005
Posts: 226
|
| Posted: Sun Jul 09, 2006 5:59 pm Post subject:
Re: 5 gallon musical water bottle
|
|
|
Glenn Sowell wrote:
| Quote: | You must have a bigger lung capacity than I do!! I have been unable to
produce a sustained note simply by blowing. The opening to the bottle
is about 5 cm diameter.
|
One gan get a about a 1/4-note with one hefty "huff" ehxale, and a lip
opening diameter of about 2 cm..
The "jug" players do a bit better with a one or two gallon jug; they
often carry the cadence of many "country" (peasant) songs .
>>Angelo Campanella |
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The Ghost
science forum Guru Wannabe
Joined: 24 Mar 2005
Posts: 115
|
| Posted: Sun Jul 09, 2006 6:55 pm Post subject:
Re: 5 gallon musical water bottle
|
|
|
Glenn Sowell <sowell2@cox.net> wrote in
news:090720060838300438%sowell2@cox.net:
| Quote: | In article
MvPrg.107079$mF2.49501@bgtnsc04-news.ops.worldnet.att.net>, Angelo
Campanella <a.campanella@att.net> wrote:
Glenn Sowell wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
That seems feasible.. filling any of them to various levels should
produce varios notes as desired.
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.
My recollection of glass 5 gallon jugs is that the empty tone is
about 30 or 60 Hz. One can ecite that tone by blowing one's breath
across the open mouth of the bottle. Wine bottle (750 ml) produce
about 120 Hz.
|
I just happened to have one of those large water cooler bottles in my
garage. It measured approximately 25cm in diameter and 49cm high and had a
5cm dia neck that was about 7cm long. A quick calculation yielded a
resonant frequency of 47Hz. The measured resonant frequency turned out to
be 46Hz.
| Quote: | You must have a bigger lung capacity than I do!! I have been unable to
produce a sustained note simply by blowing. The opening to the bottle
is about 5 cm diameter.
|
I think it's more a matter of technique than lung capacity. I had no
trouble at all exciting the 47Hz Helmholtz resonance for 7-8 seconds in a
single breath in my large water cooler bottle buy blowing across the neck
opening. I did however find that the angle of incidence of the airstream
was "extremely" critical. I was using an FFT analyzer to make the acoustic
measurement, and I saw no harmonic content in the 46Hz tone that was above
the noise floor of the room which was 70dB below the amplitude of the
fundamental. The measurement was made with the mic about six inches from
the neck opening and out of the airstream.
| Quote: | The Helmholtz frequency calculations work well for approximate
prediction of the resulting tone.
But two perturbations arise that affect tone quality:
1- The Helmholtz calculation is accurate only for sound of
wavelengths very long as compared to the length of the bottle.
2- The turbulent nature of the flow of an aistream across the opening
of the bottle produces excitation over a wide range of audio
frequencies. Sound Eigenmodes of the bottle volume of wavelengths
comparable to the dimensions of that bottle will also be excited.
Prediction of the precise eigenmode frequencies cannot be done with
the Helmholtz calculation; rather it requires the cylindrical room
method, treated at least by Morse in "Vibration and sound".
How can I excite just the fundamental? Slower moving air? By
shaping the vacuum attachment through which is blown?
Bottle modes are excited by the turbulent velocity component along
the axis of the bottle opening centerline. The usual excitation is
via the (Von Karman) vortex street caused by the airflow over the
edge of the opening; trailing from first edge encountered by the
airflow. The frequency of that series of eddies depends on the flow
velocity and perhaps the diameter of the airstream.
Where the Helmholtz eigenmode is available, it soon becomes excited
and consequently controls the frequency of the vortex shedding rate.
But it is possible to blow with such a high velocity that higher
frequency eigenmodes that also exist for that cylindrical volume are
also excited. The mode of strongest excitation, or highest "Q" will
likely dominate in turn and control the edge vortex shedding rate for
that flow condition. I would think that the parameters that are
controllable and privvy to adjustment and selection are: Flow speed,
Flow diameter, Edge sharpness and flow incidence angle to that nearer
edge.
It is all amenable to trial and error; and amenable to clever
invention.
Good luck!
Angelo Campanella
Thanks
Glenn
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Glenn Sowell
science forum beginner
Joined: 02 Jul 2006
Posts: 9
|
| Posted: Mon Jul 10, 2006 12:41 am Post subject:
Re: 5 gallon musical water bottle
|
|
|
In article <Aicsg.150922$cd2.66478@fe06.news.easynews.com>, The Ghost
<TheGhost@hotmail.com> wrote:
| Quote: | Glenn Sowell <sowell2@cox.net> wrote in
news:090720060838300438%sowell2@cox.net:
In article
MvPrg.107079$mF2.49501@bgtnsc04-news.ops.worldnet.att.net>, Angelo
Campanella <a.campanella@att.net> wrote:
Glenn Sowell wrote:
I want to make a set of musical water bottles using the typical 5
gallon bottles found on water coolers.
That seems feasible.. filling any of them to various levels should
produce varios notes as desired.
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.
My recollection of glass 5 gallon jugs is that the empty tone is
about 30 or 60 Hz. One can ecite that tone by blowing one's breath
across the open mouth of the bottle. Wine bottle (750 ml) produce
about 120 Hz.
I just happened to have one of those large water cooler bottles in my
garage. It measured approximately 25cm in diameter and 49cm high and had a
5cm dia neck that was about 7cm long. A quick calculation yielded a
resonant frequency of 47Hz. The measured resonant frequency turned out to
be 46Hz.
You must have a bigger lung capacity than I do!! I have been unable to
produce a sustained note simply by blowing. The opening to the bottle
is about 5 cm diameter.
I think it's more a matter of technique than lung capacity. I had no
trouble at all exciting the 47Hz Helmholtz resonance for 7-8 seconds in a
single breath in my large water cooler bottle buy blowing across the neck
opening. I did however find that the angle of incidence of the airstream
was "extremely" critical. I was using an FFT analyzer to make the acoustic
measurement, and I saw no harmonic content in the 46Hz tone that was above
the noise floor of the room which was 70dB below the amplitude of the
fundamental. The measurement was made with the mic about six inches from
the neck opening and out of the airstream.
Amazing. I have tried huffing & puffing at it repeatedly, with no luck. |
46 Hz sounds about right based on the note I heard with the vacuum
cleaner air source. Thanks
| Quote: |
The Helmholtz frequency calculations work well for approximate
prediction of the resulting tone.
But two perturbations arise that affect tone quality:
1- The Helmholtz calculation is accurate only for sound of
wavelengths very long as compared to the length of the bottle.
2- The turbulent nature of the flow of an aistream across the opening
of the bottle produces excitation over a wide range of audio
frequencies. Sound Eigenmodes of the bottle volume of wavelengths
comparable to the dimensions of that bottle will also be excited.
Prediction of the precise eigenmode frequencies cannot be done with
the Helmholtz calculation; rather it requires the cylindrical room
method, treated at least by Morse in "Vibration and sound".
How can I excite just the fundamental? Slower moving air? By
shaping the vacuum attachment through which is blown?
Bottle modes are excited by the turbulent velocity component along
the axis of the bottle opening centerline. The usual excitation is
via the (Von Karman) vortex street caused by the airflow over the
edge of the opening; trailing from first edge encountered by the
airflow. The frequency of that series of eddies depends on the flow
velocity and perhaps the diameter of the airstream.
Where the Helmholtz eigenmode is available, it soon becomes excited
and consequently controls the frequency of the vortex shedding rate.
But it is possible to blow with such a high velocity that higher
frequency eigenmodes that also exist for that cylindrical volume are
also excited. The mode of strongest excitation, or highest "Q" will
likely dominate in turn and control the edge vortex shedding rate for
that flow condition. I would think that the parameters that are
controllable and privvy to adjustment and selection are: Flow speed,
Flow diameter, Edge sharpness and flow incidence angle to that nearer
edge.
It is all amenable to trial and error; and amenable to clever
invention.
Good luck!
Angelo Campanella
Thanks
Glenn
|
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| Back to top |
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The Ghost
science forum Guru Wannabe
Joined: 24 Mar 2005
Posts: 115
|
| Posted: Mon Jul 10, 2006 12:54 am Post subject:
Re: 5 gallon musical water bottle
|
|
|
Glenn Sowell <sowell2@cox.net> wrote in
news:090720061941093717%sowell2@cox.net:
| Quote: | In article <Aicsg.150922$cd2.66478@fe06.news.easynews.com>, The Ghost
TheGhost@hotmail.com> wrote:
Glenn Sowell <sowell2@cox.net> wrote in
news:090720060838300438%sowell2@cox.net:
In article
MvPrg.107079$mF2.49501@bgtnsc04-news.ops.worldnet.att.net>, Angelo
Campanella <a.campanella@att.net> wrote:
Glenn Sowell wrote:
I want to make a set of musical water bottles using the typical
5 gallon bottles found on water coolers.
That seems feasible.. filling any of them to various levels should
produce varios notes as desired.
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.
My recollection of glass 5 gallon jugs is that the empty tone is
about 30 or 60 Hz. One can ecite that tone by blowing one's breath
across the open mouth of the bottle. Wine bottle (750 ml) produce
about 120 Hz.
I just happened to have one of those large water cooler bottles in my
garage. It measured approximately 25cm in diameter and 49cm high and
had a 5cm dia neck that was about 7cm long. A quick calculation
yielded a resonant frequency of 47Hz. The measured resonant
frequency turned out to be 46Hz.
You must have a bigger lung capacity than I do!! I have been unable
to produce a sustained note simply by blowing. The opening to the
bottle is about 5 cm diameter.
I think it's more a matter of technique than lung capacity. I had no
trouble at all exciting the 47Hz Helmholtz resonance for 7-8 seconds
in a single breath in my large water cooler bottle buy blowing across
the neck opening. I did however find that the angle of incidence of
the airstream was "extremely" critical. I was using an FFT analyzer
to make the acoustic measurement, and I saw no harmonic content in
the 46Hz tone that was above the noise floor of the room which was
70dB below the amplitude of the fundamental. The measurement was
made with the mic about six inches from the neck opening and out of
the airstream.
Amazing. I have tried huffing & puffing at it repeatedly, with no
luck. 46 Hz sounds about right based on the note I heard with the
vacuum cleaner air source. Thanks
|
Rather than huffing and puffing, I suggest that should simply relax, pucker
your lips and pretend that you are blowing lightly through a straw. As I
said, the angle of incidence is "extremely critical." The optimal angle of
incidence that I found is relatively shallow...on the order of 20 degrees
relative to the plane of the opening. If you are off by more than 5
degrees you can blow as hard as you want, but doing so will be futile.
When you hit the right angle of incidence, the bottle will sing loudly and
it will be obvious.
| Quote: | The Helmholtz frequency calculations work well for approximate
prediction of the resulting tone.
But two perturbations arise that affect tone quality:
1- The Helmholtz calculation is accurate only for sound of
wavelengths very long as compared to the length of the bottle.
2- The turbulent nature of the flow of an aistream across the
opening of the bottle produces excitation over a wide range of
audio frequencies. Sound Eigenmodes of the bottle volume of
wavelengths comparable to the dimensions of that bottle will also
be excited. Prediction of the precise eigenmode frequencies cannot
be done with the Helmholtz calculation; rather it requires the
cylindrical room method, treated at least by Morse in "Vibration
and sound".
How can I excite just the fundamental? Slower moving air? By
shaping the vacuum attachment through which is blown?
Bottle modes are excited by the turbulent velocity component along
the axis of the bottle opening centerline. The usual excitation is
via the (Von Karman) vortex street caused by the airflow over the
edge of the opening; trailing from first edge encountered by the
airflow. The frequency of that series of eddies depends on the
flow velocity and perhaps the diameter of the airstream.
Where the Helmholtz eigenmode is available, it soon becomes
excited and consequently controls the frequency of the vortex
shedding rate. But it is possible to blow with such a high
velocity that higher frequency eigenmodes that also exist for that
cylindrical volume are also excited. The mode of strongest
excitation, or highest "Q" will likely dominate in turn and
control the edge vortex shedding rate for that flow condition. I
would think that the parameters that are controllable and privvy
to adjustment and selection are: Flow speed, Flow diameter, Edge
sharpness and flow incidence angle to that nearer edge.
It is all amenable to trial and error; and amenable to clever
invention.
Good luck!
Angelo Campanella
Thanks
Glenn
|
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| Back to top |
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ari
science forum beginner
Joined: 11 Jul 2005
Posts: 9
|
| Posted: Mon Jul 10, 2006 9:39 am Post subject:
Re: 5 gallon musical water bottle
|
|
|
| Quote: | I just happened to have one of those large water cooler bottles in my
garage. It measured approximately 25cm in diameter and 49cm high and had a
5cm dia neck that was about 7cm long. A quick calculation yielded a
resonant frequency of 47Hz. The measured resonant frequency turned out to
be 46Hz.
I take the amplitude was p'/(roocU) < 10^-3 (p' acoustic amplitude, roo |
density of air, c sound velocity and U blowing velocity). This is, in
classic sense, a low-amplitude level case. This means that the case is
linear (as the Helmholtz frequency calculation and experiment and a pure
tone with no multiples or harmonics also suggest).
In this case acoustics or structural vibrations don't affect (no
feedback) the primary flow perturbation (vorticity).
I would expect that once the relative amplitude increases also multiples
appear and the primary frequency shifts.
BR,
ari |
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