Changing Harmonicity

[Patrick C. Poulson]

Hello All: I have a question about new strings and changing harmonicity,
which may have been covered before. I retuned an upright that I restrung
last year. The last time I tuned it I noted down the FAC numbers on the
service record. I remeasured those numbers today, and they had all dropped
an average of 2 cents. I wonder if others have noticed this happening, and
if so, how much change they noticed and an explanation for this phenomenon.
I hazard the guess that it has something to do with the stretching going on.
This is the 8th tuning I gave the piano after restringing. The last time I
tuned it was in September, when humidity was somewhat here up in the Sierra
foothills. Thanks in advance.
Patrick C. Poulson
Registered Piano Technician
Piano Technicians Guild