Tuning instability question

[John Musselwhite]

At 04:53 PM 2/5/96 -0700, John Minor wrote:

>     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

How old is it?

>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.

I work in a similar hall, where the pianos (five NY S&S and two Heintzman)
are normally stored at about 18% RH during the winter. The hall's humdidy is
boosted as high as 43% (rarely!) for some shows. Stability doesn't seem to
be much of a problem DURING concerts. BTW, the soundboards are intact on
every piano (one S&S D is from 1955) even at that dryness level (I can
hardly call it a moisture level). In the spring and summer, the storage
humidity rises with the ambient humidity, but even that isn't a great
amount. The pianos are rarely used in the summer, but once a tuning is in
they all seem stable. Once consolation is they are very well preserved since
there are no moths and few rust problems.

What I would address are the tightness of all the plate bolts and screws and
the fit of the pinblock to the flange. This should be a fairly regular
procedure on ALL screws actually, especially with offshore pianos (Oh no!
Not the "sea-level pianos" discussion again!). Once the bolts and screws are
tight, try running a business card between the pinblock and flange. If you
CAN fit it in there then that could be the problem. If the piano is under
warranty (and Hamburgs rarely are on this continent) then contact the
factory or dealer or both.

A temporary fix for this can be made by carefully tapping thin maple wedges
(with perhaps a tiny spot of glue on them) between the flange and block
where there are spaces. Cut the protuding ends of the shims off and
re-assemble. This is not an alternative to replacing the block with a new
properly fitted and dowelled block, but it does help and may buy some time.

If that doesn't help, then we need more data!  <g>

                        John

John Musselwhite, RPT
Calgary, Alberta Canada
musselj@cadvision.com