evaluating sdbd. crown & bridge downbearings in a new piano

[Richard Brekne]

Pianogreig@AOL.COM wrote:

> I'd appreciate feedback from experienced techs regarding the measuring and
> evaluating of soundboard crown and bridge downbearings as well as the
> importance
> of these readings along with the impact of factory hammer voicing on the
> quality
> of tonal production on a new high quality instrument.
>
> Yesterday I examined, while a client played, 6-7 new & "slu" $52K  pianos in
> NYC.
> I measured crown with a thread adjacent to the longest rib & bridge bearings
> with
> a Lowell bubble gauge.  Of the 2 best sounding (treble sustain, singing
> quality and
> sonority) one had very "positive" measurements while the other a nearly flat
> board
> with a slight rise toward the treble side.  The "positive" one had obviously
> been
> voiced more brightly while the second one projected beautifully with less
> brilliance.

Were these two "best" that had such different crown measurements the same make
?? Did they have the same kind of scale ?? ie low tension versus high tension ?
I think the experts are going to need a bit more to go on to make a fair
appraisel.

>
>
> I'm also curious as to the long range effects of what appear to be "pressure
> ridges" -
> the client even noticed these and asked me about them.

I assume this is in the soundboard ?? I have understood these to be a sign of
pending problems, sometimes caused by the board wanting to grow, and not having
any room left to do it in, and this can in extreme cases cause cracking in the
soundboard, and ribs pulling away.

I am NOT one of the experts in this area, but threw my two bits in as I like to
pick up any new info I can myself. SO .... if any of what I just said is
wrong... I am looking forward to being shot down, hopefully with like good
explanations.

>
>
> Bruce Greig, RPT