Double Striking Hammers

[Jim Coleman, Sr.]

Hi Avery:

After carefully setting letoff, drop, springs, drop, aftertouch, etc., 
sometimes we will find that on a very soft blow the hammer will bobble or
hit the strings a second time. When all the other things are right, the
letoff may be just a little too close. My standard is to set the letoff as
high as possible just short of the double bounce produced by a soft blow 
with stiff finger. If the jack is too far under the knuckle, this could
exacerbate the problem. And, or course, if the springs are too strong, they
could also be contributors. It doesn't matter how much extra aftertouch you
have if on a soft blow the jack does not even escape from the knuckle. This
is where you have to do something about the letoff being too high.

Jim Coleman, Sr.

On Fri, 18 Sep 1998, Avery Todd wrote:

> List,
> 
>    I'm having a minor problem on one of our 'D's with hammers that sometime
> double strike a little on very soft blows. The key(s) are being played all
> the way down but the hammers don't go into check on that soft a blow. So
> some bounce back up enough to sometimes "bubble" very softly.
>    It's happened before on another piano but I've always been able to change
> a little here, a little there, and manage to stop it. However, I've never
> really understood why it happens or what regulation adjustment would be
> *most* likely to stop it. Or is it a combination of things: like rep spring
> too strong, drop too little or too much? Dip? Something else? Comments?
>    Thanks.
> 
> Avery
> 
> 
>