Klarinet Archive - Posting 000838.txt from 2000/09

From: "Clark W Fobes" <reedman@-----.com>
Subj: [kl] Reed behavior on mouthpiece
Date: Tue, 26 Sep 2000 12:04:43 -0400

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In an earlier post I said:

"We know that the beating reed actually never touches the tip rail given =
a properly matched facing and reed strength. (If you play a very soft =
reed on a standard 1.00mm facing the reed will collapse, touch the rail =
and stop vibrating)"

Bill Hausmann countered that in fact the reed does touch the mouthpiece =
based on experiments reported by the Physicist McGinnis.

I am partially wrong in saying "never". Please read Backus, "The =
Acoustical Foundations of Music", pg 229 -231. He says:

"For soft tones the reed never touches the mouthpiece. As blowing =
pressure is increased, the amplitude of the reed vibration increases =
until for loud tones the the tip of the reed is against is against the =
tip of the mouthpiece for approximately half each cycle."

I have a problem with this statement and the nature of the experiment. =
First, Backus has no clear description of what "loud" means. To a =
musician this could mean anything from f to fff. When does the reed =
start to actually beat against the tip? Perhaps his "loud" is out of the =
range of 95% of general performance levels.His experiment or the =
experiment he refers to was done with a mechanical device that simulated =
an embouchure. In performance we tend to back off the pressure as we =
reach the loudest dynamic to prevent the reed form closing off.

Undoubtedly, any mouthpiece does have a maximum vloume of sound and this =
is most likely the point where the reed begins to touch the tip.

In any case, this does not affect my theory of "the plane of =
resistance".

Clark W Fobes

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