Klarinet Archive - Posting 000808.txt from 1998/12

From: George Kidder <gkidder@-----.net>
Subj: Re: [kl] Gas flow rate in clarinet
Date: Mon, 21 Dec 1998 19:25:32 -0500

Tony Pay wrote:

>I imagine you don't want the value to a very great accuracy: therefore,
>my suggestion is simply to take as large a breath as you can, and play
>the relevant note at the relevant dynamic (whatever that is) until your
>breath is exhausted, and measure the time (t seconds) that takes.
>
>Then do the same thing through a tube under water into a calibrated
>vessel of some sort (I seem to remember collecting gases at school in
>this way) and measure your lung capacity (V cc).
>
>The flow rate is then V/t cc per second for that note at that dynamic.

I'm sure various players vary in this, but when I attempt to sustain a note
to the maximum, I "run out of oxygen" before I run out of gas. That is, I
have to breath >out< to release excess "used" gas before taking another
breath. (Interestingly, this is not the case in attempting to >sing< a long
phrase. Clarinet seems to take very little air.) If this is the case,
Tony's method would not work.

Yes, an approximate value is all I need at this point. If I am going to
measure the gas concentrations in the tube, I need to take a gas sample. To
avoid upsetting things by the measurement system, I want the sample to be a
small fraction of the gas moving through, yet large enough to give readings
reasonably quickly. Thus my interest in the flow rate.

I remember as a kid seeing a demonstration by a trumpet player, in which he
dipped the bell into a soap solution and played for several minutes (many
breaths) without breaking the resulting bubble. Of course, on a trumpet all
the air comes out of the bell for all notes, which is not our case.

And thanks to all of you others who have contributed to this discussion!

George

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