Phil Housh asked about holes in flute pipes.

I suspect they are just about in the center of the speaking length of
the pipe.  This would tell you that they are harmonic flutes.  The pipe
puts out a pitch an octave above what it should put out considering its
full length.

In other words, if you have a 4' long open pipe it plays at a 4' pitch.
If you close the open end of the pipe the pitch jumps down to
approximately an 8' pitch.  If you leave it open and drill a hole
through the very middle of the length, the pitch jumps up an octave
to sound a 2' pitch.

The reason for this is to get the softer, breathier tone of a pipe that
is overblowing.  Sometimes they are difficult to voice since you are
not voicing the fundamental as you are on most pipes, but you must
voice for the first partial.  The tuning will still be done at the open
end of the pipe.  The hole will be usually all the way through a wood
pipe(both sides).  Often the hole is only on one side of a metal flute
but sometimes the builder put holes on both sides.

By the way, stoppering a pipe will not get you an exact octave lower.
With pipe scaling taken into account a stopper only gets you very close
to an octave lower.  The same goes for the hole in an harmonic flute.
It will not usually be in exactly the center of the length.

DL Bullock
St. Louis
http://www.thePianoWorld.com/