why does a string go out of tune?

[Don]

Hi Wim,

They go out of "unison" for more than one reason. Look at the bridge and
the placement of the pins, they don't have equal amounts of wood towards
the sounding length. Also look at the pin block. The pins do wobble back
and forth with humidity changes and those with the shortest length will
change the tension more. One interesting side effect of using *lots* of CA
on blocks is better unison stability. The pins seem much less affected by
changes in humidity in the short term. I do always recommend a dc system
when I CA. If not then the piano will (in my climate) become untuneable again.

I try to set pins and strings with no more than a mf sound level. I learned
the hard way that pounding can be detrimental to good long term stability.


At 03:35 PM 4/10/04 EDT, you wrote:
>   In a message dated 4/10/2004 2:00:24 PM Central Standard Time,
>
>  humidity causes pitch instability, why just one one string? Why not in
>all of them? Why do some strings go up, and other go down?   Wim  

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.
Tuner for the Center of the Arts

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