Re: Tapering the PVC Bore

From: Nelson Zink (zink@newmex.com)
Date: Sun Dec 01 2002 - 19:49:28 PST


Peter,

> Maybe it's time to ask why the pvc flute plays so well without a
> taper?

I've always liked the straight pipe sound. Over the years I've searched for
a plausible explanation as to why the bores of flutes, recorders, etc.
changed from straight to tapered around 1600 during the shift from
Renaissance to Baroque. A straight pipe has trouble with second octave
tuning and tapering can fix that, but it's never been clear to me if that
was the reason for tapering.

In any event, Boehm found another way to do second octave tuning and went
back to straight pipe for the flute and the change has stuck. The upshot of
all this is that I don't really understand what benefit(s) a taper bestows
to a shakuhachi. Having this truly clarified would make things considerably
easier. There are a number of issues (timbre, tuning and balance between
notes) which can be separated and dealt with in a straight forward fashion
in straight pipes. What makes the subject of shakuhachi bore even more
opaque is there is a big dose of tradition mixed in.

I've found a new way to do second octave tuning in end blown straight pipes.
Timbre is easily handled in pipes by direct setting of the aspect ratio and
balance between notes isn't much of a problem because of the regularity of
the bore. So I, like you, wonder what's so hot about a taper.

> Another question. If caste bore flutes were cast with a softer, or
> different kind of resin would they sound less harsh?

The short answer is no.
 
>A flute maker here in Washington state is making caste bore flutes that don't
>sound harsh.

I'd wager that the difference between what you hear as 'harsh' and 'soft' is
simply a matter of aspect ratio. The Washington maker probably fashions a
fatter bore.

The difference between 'brass' and 'wood' (also called string and flute)
pipes in a pipe organ isn't material (both pipes being made of a zinc alloy)
it's aspect ratio. 'Brass' pipes are the skinny ones and 'wood' the fat.

Nelson

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