Date: Tue Apr 17 13:59:53 2007

Author: Richard Berg

Subject: Re: music pipes

Post:

Anthony,

I would suggest that ALL of the instruments act as acoustical open tubes
except the clarinet, which functions as an acoustical closed tube. There
is a realy good book, The Physics of Sound, by Berg and Stork, that
discusses this. Actually, so do a number of good acoustics books. I have
never seen one that presents the list that you showed:

OPEN
flute
piccolo


CLOSED
oboe
clarinet
saxophone
trumpet
bugle
tuba
trombone
french horn

The clarinet is the only woodwind instrument that is cylindrical and has a
closed end (the reed end), thereby functioning as a closed tube.

The others, such as the oboe, basson, and saxophone families, have a reed
end, but the bore shape is conical, leading them to have resonances at all
harmonics, and thereby function as open tubes.

Brass instruments, such as the trumpet family (cylindrical) and the
cornet family (conical) function as open tubes, producing all harmonics,
due to the addition of the mouthpiece and bell to the tube.

You will find information that a reed end or a lipped end function as
"closed ends," but that fact is over-ridden by the bore shape,
transforming the apparently closed tube (odd harmonics only) into an open
tube (all harmonics).

I hope this helps.

Dick

***********************************************************************
Dr. Richard E. Berg, Professor of the Practice
Director, Physics Lecture-Demonstration Facility
U.S. mail address:
Department of Physics
University of Maryland
College Park, MD 20742-4111
Phone: (301) 405-5994
FAX: (301) 314-9525
e-mail reberg@umd.edu
www.physics.umd.edu/lecdem
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