[CAUT] pre-stretching new string?

[Richard Brekne]

Grin... further exploration reveals that in a sense both are right and 
both are wrong. Same length and pitch strings with different diameters 
will react identically to same length changes. But different length and 
same pitch strings will not. JD's observation below has a slightly 
hidden tripping point.  Halving two different length strings does not 
change their length by the same amount...  same percentage yes.... but 
not same actual amount.

Even so... the method for calculating change in pitch for change in 
length holds. An insteresting little side track this turned out to be.

Cheers
RicB

         >Sorry, but itÕs not quite a complete enough formula for
        purposes of
         >this discussion.  When comparing two strings that produce the
        same
         >pitch but with different tensions, either the original length
        will
         >be different or the diameter will be different (or both), thus a
         >similar change in length will yield a different change in tension
         >and thus pitch.


    If this were so, then the whole basis upon which musical instruments
    are designed would crumble.  When you halve the length of a vibrating
    string, no matter how much strain is on it etc., you double the
    frequency, and if you stop two unison strings of identical length but
    of different mass, and thus tension, at the same point, you will make
    precisely the same change in their frequency and they will still
    sound in unison.  If this were not so it would be impossible to play
    a guitar in tune unless the tension of all six strings were identical.

    According to Wolfenden, if the temperature changes, and one of the
    strings is well below its yield point whereas the second is close the
    yield point, then the strings will produce a beat because the less
    strained string is more sensitive to the change in temperature.  This
    is easy enough to verify by a simple experiment, which I shall do in
    the next few weeks once the new workshop is up and running.

    JD

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