[CAUT] mind bender (for me at least..)

Don pianotuna@accesscomm.ca
Tue, 15 Feb 2005 17:27:51


Hi Michelle,

As others have noted the changes are due to more than one factor. The
harpsichord gives a good clue to which is *more* important--the strings
contracting or the wood expanding. My experience is that humidity changes
are far more important that temperature over a period of hours.

With the piano the cast iron plate has a different coefficient of expansion
(or in this case, contraction) than the steel in the strings.

I believe the plate also "grabs" the wooden structures and helps to distort
the soundboard, and this plus the greater moisture conditions will cause
the instrument to go out of tune on the sharp side.

If you measure the first unwound string and then the first wrapped string
you may be amazed at the difference in pitch.

I have toyed with the idea of a "Picasso" tuning style relying 100% on ETD
measurements. The process might be tune the piano at concert temperature
and humidity (right after a concert). Wait for the hall to be dark for 48
hours. Then measure every string in the piano and store it in the
particular format your ETD uses. For the next concert tune the instrument
to these measurements.  This might have the utility of a performance
instrument that ends up better by the end of the concert than where it
started out. I'm not convinced that unisons would be sufficiently reliable
using such a methodology, but I'd love to try it all the same. The process
does mean that aural checks would essentially be useless. I suppose it is
"distantly" related to the "floating pitch" concept that we are sometimes
forced to use for "domestic" tuning.

Good luck with your concert.


At 02:12 PM 15/02/2005 -0500, you wrote:
>
>Tomorrow evening we have a 2 piano (Steinway B's) recital (Bartok) with a 
>Bach violin sonata (??) complete with harpsichord thrown in there for 
>SERIOUS fun.
>
>I have been babysitting all the instruments since Friday when they were 
>moved in there. Everyday they have been tuned.
>Heat was on.

>Anyways-I figured they would go flat being the temperature went down.
>
>Anyone have any idea why I am not thinking this out correctly??


Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.
Non calor sed umor est qui nobis incommodat

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