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The degree any string changes tension due to a change in length to any
of its segments is calculated by the formula given by Dr. Galembo. I've
posted this several times now. Again. it is <br>
<br>
Change in Tension = (E*S*Change in Length) / Original length.<br>
<br>
Where E is Youngs modulus and S is the cross section of the string.<br>
<br>
You first figure the length change, then figure the change in tension,
then add the change of tension to the original tension... then with
both the new tension and new length you can figure change in pitch.
This works for plain wire. If you actually apply this formula find out
what kinds of things need to happen to a given string for it to
experience the kind of pitch changes we observe... you immediately see
that the pitch changes we see at the tenor bridge have no (at present)
good explanation. <br>
<br>
Cheers<br>
RicB<br>
<blockquote><br>
<br>
The degree to which a string goes out of tune will be a function of the
break point percentage (BPP) when it is at pitch (thanks Ron N. for
clarifying that). The lower the BPP, the greater the change in pitch
for a given change in length. The top end of the bass section is
generally considerably higher BPP than the low tenor, and the low tenor
is usually the lowest BPP in the entire piano and thus goes out of tune
the most with seasonal changes. <br>
<br>
David Love<br>
<br>
</blockquote>
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