Humidity Change and Unisons

[Larry J. Messerly]

It seems a few weeks ago there was discussion on left, center and right
strings responding differently to humidity changes.  I was not able to
follow all this discussion.

Interesting situation today.  Chickering 5'4" 1937.  On 11-96 raised
pitch 5 cents (67 degrees, 44% RH); 11-97 raised pitch 2 cents (65 and
36%); 5-99 raised 8 cents (78 and 30%).

Today tuned at 8 cents sharp (where the piano was at A-4), temp. 84
degrees F. 72% RH.

Bass was all slightly flat at A-440+8 cents.  Tenor section, right
strings were 4-6 cents sharp, center was at the offset 8 cents, and the
left strings were 4-6 cents flat of my offset.

Trebble octaves 5-6 right strings were 8-10 cents sharp, center strings
about 4-6 cents and left strings were close to the offset.

Octave 7 all strings were sharp with the right string the sharpest by as
much as 30 cents.

Any explanations?

Larry Messerly, RPT 
Prescott/Phoenix