 The Clarinet BBoard
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Author: Eoin
Date: 2000-06-02 08:12
This is a question about the human voice. I'm a clarinetist who sings as well. The lowest note my clarinet can produce is D3, the D below middle C (in actual, not written pitch). The bass clarinet can go down to D2, the octave below this. (Some can go a few notes lower). To achieve this low note, the bass clarinet has to be very long. About 2 metres, 6 feet?
But I can sing the same D2 without any great problems. The length from my reed-like vocal chords to my bell-like lips can't be more than about 20 cm, 8 inches. How do I and other men do it? Even a women's voice which is about an octave higher than mine still seems unusually low considering the size of the woman's throat and mouth.
My first thought was that the chest and ribs act as a chamber resonator, but I've been told that in fact the chest is not a good resonator because it is full of this wet spongy stuff called lungs.
Does anybody have any ideas? Could the same principle be used to produce incredibly deep wind instruments?
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Author: Dee
Date: 2000-06-02 11:25
I believe that I have read that it is due mainly to the thickness of the vocal cords. Thick members vibrate more slowly than thin ones. The pitch is varied by changing the tension on the vocal cords. Men's vocal cords are thicker than women's so men have deeper voices (note that falsetto singing is different yet). Anyhow, this makes the voice more closely related to string instruments than to wind instruments. The air stream is the mechanism that sets the vocal cords to vibrating.
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Author: Eoin
Date: 2000-06-02 12:11
Thanks, Dee. It is certainly true that my larynx doesn't move up and down as I sing low and high notes, despite the impression given by Donald Duck, Goofy and other cartoon characters. The change of pitch must be caused by a change in tension.
But one thing worries me about this. If I breathe in Helium, my voice goes up in pitch. (Hypothetically - I haven't tried it myself). If the pitch was determined by the frequency of a vibrating vocal cord, it would not be affected by the composition of the air around it, would it?
On a different topic, what would the effect of a lungful of helium on clarinet playing be? Would the pitch gradually rise as the air in the clarinet was replaced by helium, or would it jump all over the place? I remember hearing a vocal piece "Song of the White Horse" by David Someone where the lead singer uses Helium to gliss up to an amazingly high note at the end. Is there any clarinet equivalent of this?
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Author: Mark Charette
Date: 2000-06-02 13:22
Eoin wrote:
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If the pitch was determined by the frequency of a vibrating vocal cord, it would not be affected by the composition of the air around it, would it?
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The pitch is determined by the vibration of your vocal cords, but the pitch they vibrate at is determined both by their tension and the local speed of sound. Helium is less dense, and the local speed of sound much higher than regular "air".
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On a different topic, what would the effect of a lungful of helium on clarinet playing be? Would the pitch gradually rise as the air in the clarinet was replaced by helium, or would it jump all over the place? I remember hearing a vocal piece "Song of the White Horse" by David Someone where the lead singer uses Helium to gliss up to an amazingly high note at the end. Is there any clarinet equivalent of this?
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I've done it. The clarinet pitch is significantly higher than normal. There's a paper on pitch & carbon dioxide linked in the Misc section here ("The Inhalation Sharpening Effect" (I think) by Martin Pergler).
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Author: Dee
Date: 2000-06-02 20:03
The basic equation governing sound is:
wavelength x frequency = speed of sound
Or to put it another way,
frequency = speed of sound / wavelength
The speed of sound is different for every material. So if you take a sound generator that creates a fixed wavelength (as a clarinet does for any given fingering), the frequency (or pitch) will be different for every medium. It will sound high pitched in helium, "normal" in air, and low pitched in water.
This phenomenon also explains why wind instruments will be relatively sharp on hot days and relatively flat on cold days. The speed of sound in air depends on the density of the air which in turn depends on the temperature of the air (among other things).
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Author: larry
Date: 2000-06-02 20:07
Eoin:
I hope this discussion provides you with enough material to go back into battle with Olav on the Selmer.com discussion board.
Good Luck!
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Author: Jim
Date: 2000-06-03 04:37
As a bass singer, I listen to tenors, and especially counter-tenors (men who sing in the alto range) and ask the exact opposite question! The dark humor in choir lofts attribute it to tight shorts!
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Author: Meredith H
Date: 2000-06-05 00:56
My year 12 physics teacher explained the helium quesiton in a slightly different way to what Dee has described it.
All gases have the same kinetic energy at a given temperature. Since helium is such a small atom to have the same kenetic energy it must move at a much higher speed. Hence, as it is vibrating much faster sound moves through helium far faster than through air and hence the pitch is higher (back to Dee's equation for this part).
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Author: Eoin McAuley
Date: 2000-06-05 23:30
What Dee said is certainly true and applies to all wind instruments. It does not apply to string instruments. The strings vibrate at a frequency dependent on their tension, cross-sectional mass and length, but not dependent on the composition of the air around the string. Once the note has been produced at a particular frequency, it remains at that frequency as it travels to my ear, even if the air composition changes. It can't arrive at a higher frequency than it is being produced. One easy way to think of this is, if I serve tennis balls across a net at 1 per second, they can't arrive at the other side at 2 per second, even if they go faster, because where would the extra balls come from.
It is this difference between wind and string instruments that leads me to believe the human voice is closer to a wind instrument, hence my surprise that its pitch is far lower than that of any other wind instrument of the same size.
Perhaps the voice is a combination wind/string instrument of a type that does not exist elsewhere.
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Author: Mark Charette
Date: 2000-06-05 23:43
Eoin McAuley wrote:
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It can't arrive at a higher frequency than it is being produced. One easy way to think of this is, if I serve tennis balls across a net at 1 per second, they can't arrive at the other side at 2 per second, even if they go faster, because where would the extra balls come from.
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Sure they can. It's all relative. If the person serving is running toward you and continually serving 1 per second, you'll get more than one second over the net (until the server runs into it), even at a constant speed. The flight time shortens. Doppler effect. Leslie speakers used this to great effect years back.
Of course, swinging a violin around your head to get the effect is not recommended :^)
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Author: jim lande
Date: 2000-06-06 04:58
Disclaimer: I am an economist. Economists are paid to be wrong a third of the time and trained to make stuff up.
In your throat, your vocal cords vibrate, as does the air in your lungs and mouth. The frequency of vocal cord vibrations are determined by muscles pulling the vocal cords. There may be some interaction with the shape of the mouth. I don't think the volumn of the lungs has too much effect since it is easy to close your mouth and hum the same note while going from full to nearly empty lungs. (Anyway, I don't feel like I am changing tightness or wind volumn to compensate. Think about a balloon powered horn, the pitch stays pretty constant for the first 2/3rds or so of the air. Maybe the air in the lungs doesn't actually vibrate much.)
Now, lets think about the clarinet. As pitch changes, the frequency of vibrations in the reed changes. Certainly the muscles in your mouth are very important. On a sax, you easily can jump registers without moving a finger. However, it is very hard to play a scale without using the keys. I believe that the length of the column of air is used, in part, to control the frequency of vibrations of the reed. (And the overlap between mouth shape and keys pressed is what helps with sluring notes.)
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Author: Eoin
Date: 2000-06-06 07:39
Well spotted Mark!
I left Doppler out of it to simplify the issue. Most musicians in Europe tend to be stationary, because we don't have the same tradition of Marching Bands that you have.
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