soft, bass trill regulation

[William Ballard]

At 3:53 PM -0700 8/30/05, V T wrote:
>I don't play Schubert's Sonata in B flat, but I did
>have a similar problem with a Chopin prelude.  No
>matter how gently I tried, that one note went off like
>a shotgun!  The piano barked.  It drove me crazy.  It
>only happened on my own piano.
>
>It turned out that the action center was too loose.
>Once the hammer was moving, there was nothing to
>moderate the speed.

"Fly-away-hammers". The more I think about this situation, the more 
it's like the end-of-life situation, ie., as our bodies creak on up 
through our 80s and it the 90s, what part of our body is going to 
fail first and do us in.

In the trill situation, factors like hammer center friction (present 
during the entire stroke), and escapement friction plus butterfly 
spring tension (present at the bottom of the stroke) are things the 
finger pushes against. As the trill gets quieter and quieter, these 
become a greater obstacle in comparison to what the finger is doing. 
Eventually one of these will cause the string of note-strikes to fail.

Bill Ballard