Klarinet Archive - Posting 000877.txt from 2003/03

From: "Dee D. Flint" <deehays@-----.net>
Subj: Re: [kl] Introduction
Date: Sat, 22 Mar 2003 11:37:32 -0500

----- Original Message -----
From: "Dan Leeson" <leeson0@-----.net>
Subject: Re: [kl] Introduction

> ... I still remain a confused person with respect to a wind instrumnet
> overblowing of an octave as contrasted with a 12th. Your comment above
> suggests that it is the geometry of the bore of the instrument that
> determines the nature of the overblow; i.e., conical overblows an octave
> while cylindrical overblows a 12th.

Quick summary:

Cylindrical bore open at both ends - overblows octave
Cylindrical bore closed at one end - overblows the 12th
Conical bore - overblows octave regardless of whether it is open at both
ends or closed at one end.

So it is a little bit more than bore alone.

Now we relate this to musical instruments. Some flutes and piccolos are
made as conical bores and others are made as cylindrical. Lets address the
cylindrical ones. Flutes are OPEN at both ends. i.e. You blow across a
hole at one end and the flute is open on the other end (the end is actually
the lowest open tone hole). When you overblow, it jumps the octave.

The clarinet, however, acts like a cylinder closed at one end due to the
reed action. So it overblows the 12th. It has to do with the way the sound
wave nodes form. Haven't you noticed that although the clarinet and flute
are the same length, the clarinet plays much lower than the flute? Again it
is due to the way the nodes form in a cylinder closed at one end. What
would happen if you made the clarinet a conical bore? Well you would have a
saxophone!

Notice that oboes and saxes are both conical bores. Thus regardless of the
type of reed (single or double) driving them, they overblow the octave.

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