MH BB Pinblock

[Ron Nossaman]

>   I think there is some acoustical loss in an unattached block, simply 
> because there is vertical movement in it that is not as well resisted by the mass of 
> the case.  The difference in stiffness between a block that is doweled in and 
> one that is not is profound.  

Is it? Unfortunately, I'm a couple of days past being able to 
directly test this with the piano I'm currently working on, 
but I think it's worth looking at. A dial indicator, set up 
under the stretcher and pinblock (plate firmly screwed to it) 
will tell you pretty easily. How much deflection with your 
weight on just the stretcher, and your weight on just the 
plate/block assembly? I think you'll find the stretcher to be 
considerably, possibly profoundly less rigid.


>The sound transmission is also noticeably 
> different if you tap the undowelled block then clamp it to the stretcher and tap it 
> again.  

It also is when you tap the undowelled block, and the same 
block with just a clamp attached without the stretcher because 
you've lowered the resonant frequency and raised the impedance 
of the thing with the mass of the clamp. You can observe the 
same thing by tapping the belly rail when a soundboard is out.

Ron N