[pianotech] Soundboard problem?

[Ron Nossaman]

On 12/30/2011 9:40 AM, Claude Harding wrote:

> I have done a moderate amount of rebuilding down through the years,
> including pinblocks and bridge work, but all of it
> has been on pianos where the soundboard was not a problem. I am
> thinking I have run into my first such issue.

Claude,
Much more likely, you've seen a number of them and this is the first 
you've recognized.


> The poor condition of the strings and hammers make tonal evaluation a
>  challenge, but the tenor and treble seem adequate in both

Yes, that is a problem - one of the many with evaluating soundboards by 
tone.


> volume and sustain. The bass is much weaker in both ways. Checking
> bridges and ribs for resonance and decay time with a tuning fork
> gives what seems to me to be acceptable results.

Have you tested dynamic range throughout the piano? Even the worst of 
boards can sound acceptable at a low dynamic level, and fall apart 
quickly at higher amplitudes. I know you took bearing measurements, but 
did you match those to crown measurements underneath in the same spots?

You also mentioned taking the strings off and seeing how much the board 
comes up. This is an almost universally invoked, yet utterly useless 
test, as it tells you nothing of the load capacity of the board. That 
information comes from a correlation between bearing measurements on 
top, and crown measurements directly below the bearing measurements (and 
lots of them) when the piano is still strung and at pitch.


> The piano is a family "heirloom," being fixed up to be passed on to a
>  daughter, so her 5 year old can begin lessons.

Of course.


>I think I need to get the piano
> owner in my shop, discuss the entire situation with her, then proceed
>  with caution.

I agree 120%, and the age of the piano doesn't warrant any degree of 
optimism whatsoever on the condition of the board. And that's the 
foundation. Any work put on top of a dead soundboard will be wasted. and 
then it's too late. Not to put too fine an edge on it, but lipstick on 
the corpse won't produce an acceptable prom date. <G>
Ron N