Drifting Unisons

[Roger Jolly]

Hi Ed,
          For stage work I've tried it both ways with RCT in the extreme
treble, first pass up and a second pass down for  minor corrections . In a
vain attempt to make the upper treble perfect.
P.S. I'm talking about less than 1/2 a cent. corrections.
Check the piano after a concert and after a  week and I can't tell the
difference.
 Some time ago I did some experiments, investigating string coupling, and
spent a full day getting the killer octave as close to perfect as possible.
Full blush on every string on the RCT. Each string is within .02 of 1 cent.
To achieve this I had to touch up every string many times. This was done on
a newly strung piano, so no false beat anomilies.
Only two conclusions from the exercise. String coupling effect in this
register was 0.2 cents flat.
The right hand string drifts faster than the left.
As was stated before, my educated guess is due to the lack of mass support
from the notching.
Regards roger


At 09:34 AM 08/11/99 -1300, you wrote:
>Dear List,
>	Here is another variable, that I don't think has been mentioned:
>	Most people tune unisons from left to right, so the right string is
>almost always the last to be tuned. Is there some way this could cause the
>right string to be more sensitive to humidity change? If the unisons were
tuned
>from right to left, would the pitch change be reversed?!
>	Ed Sutton
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505