[CAUT] Downbearing Error - solution - The plot thickens

[Richard Brekne]

For those of you interested :

I spent the afternoon fashioning and installing rest cushions of 5 mm 
thickness for about 2/3ds of this old grand.  After retuning I noticed 
that the sound actually got worse.  Quite a bit thinner... in the 
direction of banjo-like sound.  Then I got to thinking a bit about this 
string offset angle and this particular piano.

The back lengths range from 250 mm to 600 mm.  The tension is quite low 
compared to modern pianos... about 12500 kilo total.  I ran some numbers 
and found that compared to back lengths typical for modern pianos I'd 
have to have string offsets of way more then I started without the rest 
cushions to even come close to the same amount of actual downwards 
pressure on the soundboard.

So... as it turns out I suppose I was lucky in my error after all.  
Someone said in a response on pianotech... "Just think if you'd had too 
little downbearing".  Looks like for these back lengths, and for this 
tension level... I might just have been able to use a tad more.

Any thoughts anyones has are appreciated... but just writing this out 
and getting the little feedback I do has been of great help thinking 
this though.

Cheers
RicB