Tuning instability question

[John W. McKone]

>        We're having some trouble with our Hamburg Steinway D going out of
>tune during performances(it seems to be getting worse) and wonder if the
>extreme low humidity in the hall could be a factor. The entire building is
>without humidity, so the piano has been at 25% RH for a month now. It DOES
>jump up to 33%, but it pretty much stays at 20-25%. The question is:
>
> Will constant low humidity cause tuning instability? I'd appreciate
>answers from those who have had experience with these conditions.
>Thanks...
>
>John Minor
>Piano Technician
>University of Illinois
>jminor@uiuc.edu

John,

The humidity levels in a performance hall increase quite a bit when you
fill it with lots of (hopefully) breathing bodies.  Seems to make sense
that this effect would be more pronounced at lower starting humidity (i.e.
when the hall is empty and you are tuning)  Is the instability you mention
in the unisons, or is the middle of the piano going sharp on you?  If the
latter is true, you might try modifying your stretch to compensate.

Just a thought.

John McKone, RPT
Operations Manager
Haugen's Pianos
Twin Cities