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Re: [Phys-l] music pipes



Note also that the SHAPE of the instrument is important! Instruments
with a straight bore behave differently from instruments with a conical
bore.


OPEN
flute
piccolo


CLOSED
oboe
clarinet
saxophone
trumpet
bugle
tuba
trombone
french horn


Some sites say a trumpet is an open pipe, while others say
it is a closed pipe! Same thing was mentioned for the oboe,
bugle, and saxophone.

Brass instruments, along with reed woodwinds are considered "closed"
because they can have a pressure antinode at the mouthpiece end and a
node at the other end, as opposed to flutes, which have a pressure node
at both ends.

However, a closed tube with a conical bore has the same harmonics as an
open tube. A saxophone gets continuously larger while a clarinet is
basically uniform diameter the whole way. So even though they look
similar, they behave much differently. A saxophone has all harmonics
and goes up one octave when you go to the upper register (or when 6th
graders overblow the instrument!). A clarinet has only the odd
harmonics and goes up 1.5 octaves when you go to the upper register.

The bell on brass instruments (along with the mouthpiece) also make
brass instruments have similar harmonics as an open pipe.

Tim F