Klarinet Archive - Posting 000578.txt from 2001/02

From: Bill Hausmann <bhausmann1@-----.com>
Subj: Re: [kl] Difference Tones
Date: Thu, 15 Feb 2001 20:11:46 -0500

At 12:44 PM 2/15/2001 +0000, Tony Pay wrote:

> > > What causes the objects to vibrate at 8 Hz is the interaction
> > > between one aspect of their properties (nonlinear response to
> > > vibration), and the fact that they are being stimulated by two
> > > frequencies that differ by 8 Hz.
> > >
> > > The thing to see is that something doesn't have to be *vibrated* at
> > > a given frequency in order then to vibrate at that frequency.
> >
> > Is this not exactly what is happening to the AIR when the two pipes
> > are played?
>
>Perhaps my last sentence should have read:
>
> > > The thing to see is that something doesn't *necessarily* have to be
> > > vibrated at a given frequency in order then to vibrate at that
> > > frequency.
>
>The air, you see, is being vibrated at two frequencies, and the response
>of the air is to vibrate at those frequencies, and at no other, *because
>the air responds linearly*.
>
>However, if that air vibration in turn stimulates a system that
>*doesn't* respond linearly, other combination tones are generated in
>that system.

Linear and non-linear responses are interesting theoretical
exercises. Still, all I know is that since 1926, the organ in Liverpool
Cathedral has been producing notes as low as 8 Hz CCCCC, even though it has
no 64-foot pipes, by means of "beating" the frequencies of two 32-foot
pipes against each other. Check with Henry Willis and Sons, who built it
and also restored it in 1958-60 and added a mobile console in 1965, or
Harrison and Harrison, Ltd. of Durham, who did further overhaul and
revision in 1977-78. I'm sure they can explain how and why it works far
better than I can.

Bill Hausmann bhausmann1@-----.com
451 Old Orchard Drive http://homepages.go.com/~zoot14/zoot14.html
Essexville, MI 48732 ICQ UIN 4862265

If you have to mic a saxophone, the rest of the band is TOO LOUD!

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