Re: Brass instruments

[Leigh Palmer <palmer@SFU.CA>]

> In the case of the clarinet (single reed) it is NOT the case that the reed
> just makes noise and the tube selects only the frequency it wants to
> "amplify".  The tube _forces_  the reed to vibrate at the selected
> frequency -- selected by musician key press -- and the mouth does little
> more than supply air.

No! The reed is tuned (with the lips and strength of the air stream*)
to open and close at the frequency of the reflected standing wave. It
is similar to the brass instruments in that way. It doesn't work like
a keyboard instrument.

> On the other hand for double reeds one CAN play a tune with just the mouth
> and reeds so I take it that the oral cavity (by changing shape) can force
> the reeds to vibrate at the frequency of choice -- and the note is
> "amplified" by the tube accompanied by the simultaneous key pressing.
>
> Sort of.

Indeed. Adjustment of the mouth cavity does affect timbre. (I really
wish you would use the conventional meaning of "amplify".)

There are instruments which have capped reeds. The reed does not go
into the mouth and cannot be tuned. The sound is similar to that of
the voice of a laryngectomized person talking with a "buzzer" on his
throat (the krummhorn) or worse (the bagpipes). In the latter case
the drone reeds play but a single note, so tuning them actively is
not a problem. I have no idea what happens at the chanter reed, but
I suspect it's a bit like the krummhorn.

Leigh

*The air stream pressure is only very slowly varying over the pitch
midrange according to several workers.