[CAUT] Restringing treble

[Gary Mushlin]

It seems to me that the following may  prove this theory.

The next time you experience a broken string, measure the pitch change 
on adjacent strings/notes. Then press down on the bridge about 7 lb. 
worth. If there is no effect on the pitch on these adjacent strings, 
you will know it is not the downbearing change on the bridge causing 
the pitch change. After the new string is installed, check the adjacent 
strings again.

Do you think this will prove the point? I've not done this, but I will 
do this the next time the situation occurs. This has been enlightening, 
because I've always heard that pitch change takes place due to the 
change in downbearing on the bridge and soundboard.

Sincerely,
Gary Mushlin, RPT


On Dec 31, 2004, at 11:17 AM, Ron Nossaman wrote:

>
>> I have measured
>> soundboard drop under tension, and it isn't uncommon to see them drop 
>> .050" when the
>> piano is chipped to pitch.  Some more (such as the Chickerings with 
>> the inner
>> rim), some less (Steinways and Baldwins), but there is still a lot of 
>> movement
>> up and down.
>> Regards,
>>
>> Ed Foote RPT
>
> Not from one broken string, there isn't. That's about 7 lbs of 
> downbearing on the bridge, and about 300 lbs of pull on the plate. 
> Also consider the directions the movement of plate and bridge 
> respectively take. For example, take an arbitrary string of 150mm 
> speaking length, 50mm rear duplex, and 1° downbearing. Bridge rise of 
> 0.0245mm (0.001") will change those lengths a total of 0.00045+mm 
> (0.000017+"), where you will get a nearly 1:1 relationship with plate 
> deflection from tension changes and string lengths. No contest.
>
> Ron N
>
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