Klarinet Archive - Posting 000165.txt from 1996/10

From: "Scott D. Morrow" <SDM@-----.EDU>
Subj: Re: CO2 influencing pitch
Date: Tue, 8 Oct 1996 15:28:44 -0400

Jeroen T. Salm wrote:
>When I had my lesson with Karl Leister about second movement of Schubert
>Oktet, he told me, to take a breath (deep, 'cause the frase will be long),
>hold the breath for about 4 seconds and only after those 4 long seconds
>begin playing, otherwise the first note/tone will be too high (in pitch).
>Indeed, always when I start a long frase with a long tone,this method is
>the only way to get a good pitch (i.e. not to high). Just inhaling and play
>for it causes a to high beginning (as we here so often).
>I think this also has to do with CO2?

>

Leonardo Fuks wrote:
>Luuk van Buul, our dear Dutch Carnival player, reports his interesting pitch
swinging during his beer-CO2- driven tones.
He is completely sober about that:
The sound speed in air (at 0 C) is 331.8 m/s and from the CO2 it is 258.0
m/s . CO2 is much havier than the air mixture (which contains less than 0.1
% of CO2 outdoors). The air column of the instrument resonates in a way that
is proportional to the sound speed, so the pitch of the fundamental and all
the overtones are proportional to c (sound speed).
If Mr. Bull is able to accumulate a lot of CO2 from his beer (hope it's
better than Heinecken :)), he is supposed to transpose 4.4 halftones lower.
What actually happens is that the CO2 is mixed with the air in his lungs
(+throat, mouth, airways), reducing the pitch fall.
By the way, even with discrete differences in the percentage of CO2, as
reported in my last message
(Re:odd comment (acoustics)-CO2), some variation in pitch may happen. I
estimate that from 3.5 % to 7.5% of
CO2 a maximum lowering of 37 cents (37/100 of half-tone) will occur. Try to
play a tone with very fresh air, just after a deep and fast inhalation, in
front of an electronic tuner. Then play the same tone after a long period of
breath holding. If you keep the same embouchure you may find that. Please
report me about your experiments and ideas, what will be very helpful in my
research.

I SAY:

Perhaps I am just unenlightened, but, in the absence of a more
colourful Dan Leeson characterization, I find this all sounds like a lot of
nonsense!
First of all, I have read NOTHING in this discourse that could even
remotely suggest that any change in pitch could be related to the CO2
content of the air being forced through the clarinet. Everything I've read
here - from belching to breath-holding- sounds more like the effect of
proper air-column support and effective use of the diaphragm (THAT's why
you'd wait a couple of seconds after taking your breath before attacking)
on the pitch rather than from the gas mixture in that air in our lungs!
Secondly, even if sound travels faster or slower in CO2 than in N2,
it is completely irrelevant because we are not LISTENING to that sound
travelling through CO2: we are listening to it travelling through AIR
(N2). So, unless you are a volcano and the amount of air you blow through
your instrument can drastically affect the air composition in the room
around you, IT DOESN'T MAKE ANY DIFFERENCE!
My proposal is:
The soundwaves emanating from the clarinet are dependent on
the acoustics of the instrument and the air support used to create the
tone.
The composition of that air, alone, does not affect the pitch.
The pitch MAY be altered by reduced air column support
caused by ineffective use of the diapragm and breathing techniques (i.e.,
hyperventilation, etc.) and relaxation of the embouchure due to fatigue or
loss of control as a result of overriding bodily functions (i.e., belching,
coughing, smiling, etc.).
If you drink and play, please make sure you have a
designated soloist!

-Scott

Scott D. Morrow
Department of Biochemistry
School of Hygiene and Public Health
Johns Hopkins University
(410)-955-3631

SDM@-----.edu