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Brass instruments



On Wed, 7 Jul 1999, Jim Green wrote:

Leigh, the trombone, trumpet, bugle and I suppose other brass are clearly
harmonically driven -- musicians please speak up here -- ie the lips must
vibrate at the frequency of the desired note -- or maybe at an
harmonic. The instrument is merely a resonant cavity to amplify the sound
made by the lips -- as opposed to the winds and reeds, which amplify broad
spectrum noise in the case of the reeds and define the frequency in the
case of the winds.

However I am not sure of any of this. (:-)
The vibration of the lip that brass players use to initiate the sound
sounds not unlike the 'breaking of wind', absent a mouthpiece, horn and
accoutrements. The lip can be tightened muscularly or loosened to shift
the maximum in the vibrational spectrum of the input to the mouthpiece but
it is definitely a broad spectrum emission. The 'tone' of a beginner
sounds funky compared to that of an experienced player because the latter
is more skilled at approximating the input spectrum's maximum to the
desired output, but even a Maynard Ferguson's input was a spectrum broad
enough to make its 'pitch' indeterminant.
I am not a reed player but I think players of true reeds, even
flautists, do the same crudely by varying pressure on the cane reed or
lips to effect a different input for high and low registers.

John N. Cooper, Chemistry
Bucknell University
Lewisburg PA 17837-2005
jcooper@bucknell.edu
http://www.facstaff.bucknell.edu/jcooper
VOX 570-577-3673 FAX 570-577-1739