[pianotech] new board evaluation

Ron Nossaman rnossaman at cox.net
Sun Dec 7 14:00:03 PST 2008


> What's the back scale length of A-0?
> 95mm

Not an awful lot. Is that all the room there was?


  > Bass rescaled?
> Only slightly - reduced spl to get slightly longer tail lengths.

What was the original A-0 back scale?


> What's the core diameter of A-0?
> .058

Still fairly stout. I'd say it's likely a combination the 
board being too stiff, with the back length, and core diameter 
contributing. Up to about 6-1/2' (200cm) I float the tail 
around the low bass too. The bridge is for sure clearing the 
edge of the plate, right? I recently had an embarrassing 
reminder of how easily that can happen.


> What "design" board did you build?
> Radius cut ribs - 60 ft in the bass and tapering to the treble - 16 
> total. Made from quartered Sitka. Glue up at around 6 to 6.5 mc.

What method did you use to determine the count and 
dimensioning of the ribs?


> The board was not cut off in the bass but the inner rim gluing surface 
> was built up with epoxy and veneer to accomidate the part of the board 
> that did not want to go down on the rim without a struggle.

Why not, and why?


> Thickness is 9mm - on the fat side - no diaphraming.

Again, why?
Ron N



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