Klarinet Archive - Posting 000175.txt from 2010/08

From: Jennifer Jones <helen.jennifer@-----.com>
Subj: Re: [kl] About clarinet acoustics
Date: Mon, 16 Aug 2010 18:59:12 -0400

On Mon, Aug 16, 2010 at 1:07 PM, Jennifer Jones
<helen.jennifer@-----.com> wrote:
> On Mon, Aug 16, 2010 at 11:53 AM, Tony Pay <tony.p@-----.org> wrote:
>> On 15 Aug 2010 at 11.15, Jennifer Jones wrote:
>>
>>> It appears there are some end effects that make the (L+2a) approximation not quite
>>> correct in the presence of a bell, as indicated by the section "End
>>> corrections are more complicated in real instruments" at (4)
>>> http://www.phys.unsw.edu.au/jw/musFAQ.html#end.

OOPS. L+0.6a not what I wrote above

Making a revised calculation for the clarinet without a bell:

Making this [58.3 + (1/2)*0.6*2.4] or 58.3 +.7 = 59 cm instead of
60.7. 59 cm minus Diego's 58.5 cm 1/4 wavelength of concert a
(clarion b) is 1/2 cm from the tip of the mouthpiece. I can't measure
the frequency of my concert a. My tuner is packed away and may not be
sophisticated enough.

The sharpness of chalumeau E and clarion b without the bell:

Low E, sharper without the bell; clarion B/concert A sharper than 445
Hz, means higher frequency and shorter wavelength, moving the node
towards the bell, lower than the 2.5 cm or the 1/2 from the tip of the
mouthpiece.

sound speed/frequency = wavelength

Concert a (clarion b) has 1/3 the wavelength of chalumeau E (interval is a 12th)

so,
(sound speed/frequency of clarion a = wavelength of clarion a)*3 =
wavelength of chalumeau E; frequency is bigger, which is in the
denominator, so the wavelength is smaller and the node is farther down
the clarinet; more than 0.5 cm below mouthpiece tip,

still less than 8 cm below? Diego's calculation is established as a
reasonable estimate.

-Jennifer
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