Klarinet Archive - Posting 000398.txt from 1995/03

From: "Edwin V. Lacy" <el2@-----.EDU>
Subj: Re: flatness at higher dynamic levels
Date: Mon, 13 Mar 1995 23:44:48 -0500

Dick Williams wrote about the apparent lowering of the pitch level when
increasing the dynamics.

This phenomenon exists for ALL reed instruments. (The flute works in
just the opposite way - but that's not only another subject, it's a
different BBS.)

If the player could increase the breath pressure and alter no other
factor, the pitch should rise. (Greater pressure = faster air speed =
higher pitch) But, in order to get more air into the instrument to
achieve the higher intensity level, the player will consciously or
subconsciously reduce the embouchure pressure on the reed, thereby
allowing for a wider tip opening to accomodate the greater air flow.
This opening of the reed tip effectively increases the total interior
volume of the instrument, which has the same effect as increasing the
bore of the instrument, and thereby lowering the pitch. So I agree with
the person who said that the effect is caused by the player.

That is one of the big problems of the woodwind quintet and similar
ensembles which involve both the flute and reed instruments. As the
dynamic level increases, the flute tends to go higher while the other
reed instruments tend to go lower. But, expert players will compensate
in other ways for this change, so that the overall effect is that the
pitch remains the same.

That at least is my recollection of my acoustics course from about 35
years ago!

Ed Lacy
el2@-----.edu