Klarinet Archive - Posting 000126.txt from 1996/05

From: "Jonathan A. Cohler" <cohler@-----.NET>
Subj: Re: A question about acoustics
Date: Tue, 7 May 1996 13:51:00 -0400

On Tue, 7 May 1996, Teri Herel wrote:

> In a message dated 96-05-06 10:37:50 EDT, you write:
>
> >On Mon, 6 May 1996, Jonathan Cohler wrote:
> >> At 9:35 PM 5/5/96, Lisa Clayton wrote:
> >> >> cylinder, but there is no common orchestral instrument that is an open
> >> >> cone, but if there were, it too would oveblow a 12th.
> >> >> Ginny Lyons
> >> >
> >> >Is there an uncommon instrument out there that is an open cone?
> >>
> >> The early music folk probably know better, but I believe there were old
> >> conical flutes. Those would have been open cones.
> >
> >Unlike today's cylindrical flutes, most of today's professional quality
> >piccolos (and many intermediate ones) have (reverse) conical bores --
> >wider at the headjoint and narrower at the foot. Yet they do overblow an
> >octave and do produce all even and odd harmonics. I seem to recall that
> >the advantage of this bore shape is an improvement in intonation in the
> >high register. Can you explain the physics?
> >
>
> My physics texts are (thank God) buried deep within the depths of my attic,
> however, we must keep in mind that the models we are discussing here are
> simplified, i.e., the clarinet is not an ideal cylinder open at one end, nor
> is the flute an ideal cyllinder open at both ends, but rather empirically
> developed systems that for the most part function as these models. So the
> fact that the piccolo has a slight inverse taper would not change it
> functioning as an open ended cylinder until the ratio of the taper becomes
> relatively much larger.
>
> Teri Herel
>

Exactly.

There are even slightly conical sections inside most clarinets. The lower
joint of the clarinet is usually slightly larger, and there are many
reverse cone barrels.

These are slight adjustments that effect the relative tuning of the
harmonics.

---------------
Jonathan Cohler
cohler@-----.net