Klarinet Archive - Posting 000580.txt from 1998/02

From: George Kidder <gkidder@-----.edu>
Subj: Cylindrical bore in brasses
Date: Sat, 14 Feb 1998 20:58:25 -0500

This is not really a clarinet question, at least directly, but perhaps
someone out there knows the answer.

We are told that the reason why the clarinet family overblows at a 12th is
that the clarinet is 1) a closed pipe (by virtue of its read) with 2) a
cylindrical bore. The oboe, bassoon and saxophones with their conical bores
overblow at the 8ve even though their reeds are (somewhat) like ours. The
flute, by contrast, is a cylindrical bore, but is an open pipe, and
therefore also overblows the octave.

Among the brasses, there are instruments with bores which are cylindrical
throught most of their length (trumpet, trombone) and those with conical
bores (cornet, tuba). I would think that the lips of the player would
function similarly to the reed, and that these would therefore be closed
pipes. I am assured by competant players that both classes of brasses
produce an 8ve as their first note above the fundamental?

What is the error in my thinking? Why doesn't the trumpet have a different
harmonic arrangement than the cornet, to the extent that its fingering is
different? Is this due to the much greater length/diameter ratio of the
brasses compared to woodwinds? Is my assumption of a closed pipe wrong?

Any thoughts from the acoustics experts on this one? (Maybe Robert Howe is
recovered sufficiently from the Reunite to attempt this one as well.)
George Kidder
gkidder@-----.edu