In message <f37cce1d-f6c6-4225-a602-8738e787e...@ultrasw.com>, Paul
Scott <psl...@ultrasw.com> writes
On Apr 3, 2009, at 3:49 PM, Anthony W. Youngman wrote:
In message
<7ca3d5a30904031519ya3b89hb87cf8f81a544...@mail.gmail.com>, Neil
Puttock <n.putt...@gmail.com> writes
2009/4/3 Anthony W. Youngman <lilyp...@thewolery.demon.co.uk>:
In message <mj9t1jgcvk1jf...@thewolery.demon.co.uk>, Anthony W.
Youngman
<lilyp...@thewolery.demon.co.uk> writes
Ow!
Sorry, reading this was painful (I play the trombone, as many of
you know
:-)
Replying to myself ... Just in case anyone didn't realise (and I
certainly
didn't make myself clear :-) these are my revised versions that I
think
should replace the existing entries. Feel free to edit and improve.
For example Concert A is 440Hz, the speed of sound in air is
343m/s,
therefore an A clarinet (or any other A wind instrument) will
have a length
of 343/440 = 78cm. (Or be a power of 2 longer or shorter.)
Concert A is definitely not the fundamental for an A clarinet: it's a
cylindrical tube stopped at one end, so the wavelength of the
fundamental is four times the length. Since the lowest note on a
clarinet is usually the E below middle C unless it has an extension,
the fundamental would be C sharp (D on a B flat).
Ummm ... I think I might be getting physics fundamentals confused
with musical fundamentals. But I'm COMPLETELY puzzled at your
statement that the wavelength of the fundamental is FOUR times the
length. I would guess the trombone is also "a cylindrical tube
stopped at one end", and the wavelength of any note played must be
an integral number of half-wavelengths. So we have 1/2-wavelength
giving me a pedal Bb, 2/2 giving me the fundamental Bb, and 3/2 giving me an F.
I don't see how the physics would work to give you a quarter-
wavelength as you claim.
I just did some quick online research and he is right. A tube closed
on one end like a clarinet or trumpet has a wavelength that is four
times the length of the tube. A flute is open on both ends so it has
a wavelength of double the length of the tube.
Okay, I've just looked up "standing wave" on Wikipedia, and it seems
you're right about the "four times". I can't reconcile that with brass
instruments though. The first four open notes on a Bb instrument are Bb,
Bb, F, Bb. To me that's saying the wavelength is 1/2, 2/2, 3/2, and 4/2
the instrument length, and NOT 1/4, 3/4, 5/4 and 7/4 (Wikipedia says
that for a quarter-wavelength, only the odd numerators are available).
Can anybody explain?
Cheers,
Wol
--
Anthony W. Youngman - anth...@thewolery.demon.co.uk
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