Klarinet Archive - Posting 000193.txt from 1995/02

From: Jon Delorey <Jon_Delorey@-----.COM>
Subj: Re: Caution More Physics!
Date: Thu, 9 Feb 1995 07:56:36 -0500

RE>>Caution More Physics! 2/9/95 7:16 AM

In response to Jonathan Cohler's response.......

>> I don't understand this statement. A non-linearity is needed in order to
>> produce non-harmonic partials.

>The "natural modes" or "resonances" of the tube are determined by the shape
>of the tube. An "ideal" cylindrical tube closed at one end will have
>integer multiple modes for wavelengths long compared to the width of the
>tube. Any deviation from perfect cylindrical shape will modify the modal
>frequencies. One can measure the input impedance curve (the resonance
>curve) of the clarinet by measuring resultant pressure (using a microphone,
>for example) divided by input air volume using a speaker as the resonator.
>Varying the frequency of the produced by the speaker over the whole range,
>you will find that a clarinet has modes (resonances) that are slightly
>flatter than the odd integer multiples (and they get flatter as you go up).

This is exactly the point I didn't understand and I think the source of the
confusion. Each mode may become slightly flatter in frequenecy. In other
words if you over blow a 12th it will be slightly flatter than the first 12th.
Each of the partials produced from the original or overblown 12th will still be
interger related. The overblown 12th becomes the fundamental in this case. Is
this what you mean?

==================================Jon Delorey============
Jon_Delorey@-----.com
The following is the legal disclaimer:
The opinions expressed here are my own
and not those of TRW Inc.