Re: Downward reed curvature!?

[Pat Missin <pat@xxxxxxxxxxxxx>]

Nidalap wrote:
>
>  I've learned from some harp customizing gurus that adjusting reed
>  curvatures help inprove performance. All the information I got say
>  the curve has to be a upward one, that is, bent down from the rivet,
>  then up somewhere near the middle or end of the reed.
>
>  Recently I borrowed a book from libray, which explains the physics
>  of  musical instruments. I'm quite confused when I read the part about
>  free reed instrments, a figure displays a typical harmonium reed,
>  which has a downward curve.
>
>  The book pointed out the curvature, but didn't seem to explain it.
>  I am very curious why a downward curve is applied, could somebody
>  please help me find out the answer? thanx!

There are many different voicing curves used for reed organ reeds,
many of them involving a setting that rises up in the middle of the
reed and downwards towards the tip. Twists are often applied to the
reed too.

The short answer is that despite the similarities between reed organ
reeds and harmonica reeds, the playing conditions of the reeds are
quite different and most of the settings used for reed organ reeds are
inappropriate for harmonica reeds. Curving harmonica reeds downwards
towards the tip makes them sound muffled and also causes their pitches
to vary quite noticeably at different pressure levels. 

 -- Pat.