[CAUT] Wire Stretch

[John Delacour]

At 9:57 pm -0500 28/4/07, Tim Coates wrote:

>I think Jeff Tanner asked a question that was interesting.  There 
>was a lot of discussion about crushed bridge surface causing the 
>pitch to drop, but then the thread changed to wire stretch causing 
>the pitch to drop.  I thought his question was: which is it?   I 
>don't believe I've seen anyone answer his question yet.

It's easy enough to calculate.  If you have C76 of length 100mm at 
pitch when lying on the surface of the bridge and then lower the wire 
0.5mm into the top of the bridge (some indentation!) then, all else, 
being equal, the frequency of the string will drop about 0.026 Hz. 
producing one beat per 40 seconds against the proper frequency.  The 
difference will be even slighter as the strings get longer.

JD