Re: [Harp-L] Reed gapping questions

[Vern <jevern@xxxxxxx>]

On Sep 13, 2013, at 3:53 PM, pneupco@xxxxxxxxxxxx wrote:
>  Anyway, the rule of thumb when gapping is that the gap should be as wide as the reed end is thick.

Wrong.  Most gaps are  wider than the end is thick.  Tuning can change the end thicknesses.

I am sending you a gapping chart in another email (harp-l doesn't allow pictures) that will help you judge reed gaps based on the length/pitch of the reed. It is based on measurements of many reeds. IF you use the chart, I'll guarantee that your reed will play well in ordinary circumstances.  Use it as a starting point.  If you wish to bend or overblow, then the gaps are a little bit smaller and you'll have to fiddle around more with them to find the optimum.  I'm not sure, but I think that for gapping and overblowing you use the smallest gap that will allow the reed to start promptly. Maybe some bending and overflow experts have something to add.

If you are dealing with one reed on an otherwise well-gapped harp, the gap should be between the heights of the gaps of the neighboring reeds.

> OK, so what does either increasing the gap or decreasing that gap do to the sound produced and/or the playing characteristics of that reed?

IF the gap is too small, the reed will be balky and reluctant to start, then choke if you play hard.  IF the gap is too large, the reed will sound wheezy and might not start at all.  A well-gapped reed will start at about .5 inches of water breath pressure and not choke at 10-12 inches of water.
I know, you don't have a way of measuring breath pressure.  I can tell you how in another email.  

Except maybe for bending and overblowing, gapping isn't as critical as you might think.  Small changes of gap within the acceptable range won't much change the sound.

Vern