Klarinet Archive - Posting 001404.txt from 1998/10

From: "Doug Sears" <dsears@-----.org>
Subj: Re: [kl] re:Altitude pt 2
Date: Sat, 31 Oct 1998 13:52:03 -0500

Very interesting calculations, but your speed of sound at sea level
doesn't match the number you plugged into the formula for f1:

>Speed of sound at sea level at 0 C @-----.3 M/s
>f1 @-----.30 / 2(l + S/c) (sea level)

Correcting this to:
f1 @-----.3 / 2(l + S/c) (sea level)
f2 @-----.27 / 2(l + S/c) (5000 ft)

gives a ratio of .988, and 440 Hz at sea level becomes 434.6 Hz at 5000
ft, a more believable change, IMO, and still pretty significant.

--Doug
---------------------------
Doug Sears dsears@-----.org/~dsears

-----Original Message-----
From: Mark Charette <charette@-----.org>
[...]
>Speed of sound at sea level at 0 C @-----.3 M/s
>Speed of sound at 45,000 ft at 0 C @-----.0 M/s
>
>Doing a linear interpolation ( a dangerous
>assumption, but who cares at the moment - we
>can lip things up or down to make 'em right :),
>the speed of sound at 5000 ft would be:
>
>327.27 M/s
>
>Using a ratio (since the other variables will
>remain about the same - c changes a tiny, tiny bit):
>
>f1 @-----.30 / 2(l + S/c) (sea level)
^^^^^^
>f2 @-----.27 / 2(l + S/c) (5000 ft)
>
>f2 will be lower than f1 by a ratio of .962,
>therefore (again, this is approximate):
>
>A fingering for Concert A (440 Hz) at sea
>level produces 440 * .962, or 423.28 Hz at 5000
>ft - just a wee bit flat :)
>[...]
>----
>Mark Charette@-----.org

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