The Clarinet BBoard
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Author: Rene
Date: 2001-01-27 10:11
Can anybody explain to me how the register key works from the acustical point of view?
I think I understand, why the clarinet resonance length ends at an open hole. As I understand this is the point of most air movement and least pressure change. So this point determines a quarter of the wave length. However, I have no idea, why the register hole cuts away this frequency and leaves only the third overtone.
Rene
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Author: jbutler
Date: 2001-01-27 12:23
When equally strong compression waves are coming at each other from opposite directions they obviously cancel each other out creating a displacement node at the meeting place. Their pressures combine to form a compression antinode at the meeting place corresponding to the displacement node.........Each of the registers correspond to an odd numbered multiple of low register frequencies, which is to say that the sequence of the different registers should follow the odd-numbered harmonic series. (Ferron pp 10-11)
I'm not a physicist (don't know if I even spelled it correctly) but I think I understand it from reading Ferrons book: The Clarinet Revealed published by International Music Diffusion, c. 1996)
John
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Author: William
Date: 2001-01-27 14:05
In other words, when you experiance an unauthorized compressive antinode, ........you squeak!
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Author: Bill
Date: 2001-01-27 15:43
Sorry, the link doesn't get you directly to clarinet info. Go to the web page, select Sound and Hearing, then Musical Instruments, then Woodwind Instruments, then Clarinet, then Further Details, then Register Key and Further Details. It's easier than this looks, and worth the visit.
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
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Author: jbutler
Date: 2001-01-27 17:53
Thanks for the link, Bill. Yes, that is what I was trying to describe, but didn't quite know how to put it in words to convey the proper meaning. In other words the fundamental is "destroyed" for a lack of better term, leaving the third harmonic.
John
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Author: Rene
Date: 2001-01-29 05:22
Thanks for the link from here too.
Still I do not really understand it. Why does the first mode have a pressure node at the point of the register key, while the third overtone has none?
Maybe my idea of the air column inside the clarinet needs to be revised. Hmmm, thinking ...
Rene
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Author: Gordon (NZ)
Date: 2001-01-31 09:47
Doesn't the diagram show the third overtone with the pressure node at the register key? I'll have to check.
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