Buttressed Arch. Question for Ron N.

[John M. Formsma]

Rons,

So, bear with one of the guys who feels a little slow in getting all this
through a thick skull...hitherto I've focused on servicing these pianners
rather than making the design better, although it's always been quite
fascinating.

I think what you're saying is that mass in the rim and on the rim via the
plate is good. Right? 

Now, the impedance under consideration is the ability to resist energy from
the board into the rim where it's dissipated, if I'm getting it. So, more
mass = more impedance = more sustain, huh?

OK, next. If more mass is good, what about the theoretical possibility of
having the most massive, densest material as a rim to which the board was
affixed somehow? Just for theoretical consideration, would that make it
better theoretically?

Practically, what better material could be used than what is currently used?
I mean, it seems like you could actually get about anything to work, but the
heavier you make 'em, the less likely they would be bought b/c they would be
so difficult to move.

Thanks from someone whose head impedance is pretty high. <g>

John Formsma

> Following on from Ron N's comments on the mass loading of rims, and its 
> impedance benefits, I've suspected for some time that heavy plates help 
> sustain. I think its one of the reasons why the Baldwin SD-10 is such a 
> remarkable instrument. The benefit of using a denser timber such as rock 
> maple for the rim may have as much to do with the mass increase as 
> stiffness.

I agree, both counts. Load 'em up.

Ron N