Evident in the top half of the scale: distortion on a medium to hard
blow, diminished sustain. Check bearing and crown everywhere in the
piano you can reach, not just on the long rib as we were all taught.
There should be positive bearing over positive crown everywhere. If not,
the soundboard isn't structurally doing it's job. It may sound
acceptable in high humidity seasons, and horrible when it dries out.
You'll get the call, naturally, when it's dry. They'll want that killer
octave voiced away. It sounded fine a couple of months ago, so maybe it
was something you did last time you tuned it. There aren't any checklist
numbers or go/no-go gauge for automatic diagnosis. It's a matter of how
far gone it is, and whether it's past the owner's tolerance threshold.
We've all heard so many dead soundboards, we tend to accept them as
normal, but if you spend some time with a well functioning board, it's
hard to listen to the usual stuff again. Distortion and limited spectrum
are present in the low half of the scale as well, but it's not as
dramatic and obnoxious as killer octaves and trebles that "dink"
typically are.
Ron N
Original Message------
> Cracks are not the end of the board but loss of crown is.
Yes it is, and if there are loose ribs at all, the soundboard is trash.
Ron, all: What sonic reasons merit a new board or are they mostly vetted and valued by eye? For instance what are typical before and after ring times? Is there a favored ratio of ring time decline from bass to treble? Is dynamic contrast objectively measurable and are there known volume and sustain times to aim for? Down bearing measurements are often mentioned. What else please?
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Paul Klaus
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