Klarinet Archive - Posting 000121.txt from 2010/08

From: Jennifer Jones <helen.jennifer@-----.com>
Subj: Re: [kl] Location of antinodes of vibration in an air column
Date: Sun, 15 Aug 2010 05:23:04 -0400

On Sun, Aug 15, 2010 at 2:14 AM, Tony Pay <tony.p@-----.org> wrote:
> On 15 Aug 2010, at 00:18, Keith Bowen wrote:
>
>> I, too, am surprised that the distance from the reed tip to the antinode=
is as much as 8 cm. This doesn't correspond with some quite detailed measu=
rements and calculations I made last year of bass clarinets to determine th=
eir pitch (not being allowed to play museum specimens).
>
> I think I see where the 8cm problem is. =A0Diego has made the assumption =
that the 'speed of sound' in the clarinet tube is the same as the speed of =
sound in open air.
>
> But we know that that speed can vary according to other parameters -- for=
example, the 'shoelace-down-the-tube' experiment, that changes the pitch o=
f a clarinet as much as a semitone, demonstrates it. =A0And I seem to remem=
ber (stuck here in Siena without access to references) that there is someth=
ing about the diameter of even a theoretically smooth tube....
>

What about the end effect approximation? The "End corrections are
more complicated in real instruments" section at
http://www.phys.unsw.edu.au/jw/musFAQ.html#end indicates that the end
effect approximation is more complex than L+2a for instruments with
bells. I have followed several links so far and have not found
anything more specific than that yet.

-Jennifer
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