Klarinet Archive - Posting 000148.txt from 1996/10

From: Leonardo Fuks <leonardo@-----.SE>
Subj: Re: CO2 influencing pitch (in beer drinkers).
Date: Mon, 7 Oct 1996 18:51:44 -0400

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 am also receiving any brand of beer that you can donate for some
experiments during next Stockholm Carnival...
All the best
Leonardo

van Bull wrote:
>I have some experience on this subject. Once a year I play at the Carnival
>festivity here in the south of Holland with a small band. We drink lots of beer
>during those days and we play a lot of music, very loud and for the clarinet
>very high also (just remove the register key :) ).
>The beer in my stomach contains lots of CO2 and this is pressed out during
>playing by applying the firm pressure needed to blow. So, sometimes, I belch
>while playing. This brings lots of CO2 in my breath and in the clarinet. The
>pitch is immediately affected and lowers for about a quarter of a tone, and
then
>climbs slowly back, up to the old pitch.
>
>Luuk van Buul

   
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