longitudinal mode vibrations

[Ron Nossaman]

>List,
>
>What is the relationship, if any, between string torque and longitudinal
>mode vibrations?  

Hi Paul,

* I don't believe you got any bites on this one, and I think that's because
nobody has established any such relationship.  


>When there is torque in the string, I presume there is
>torsional movement, and my guess is that it would be longitudinal. 

* I'm not sure what you mean here... that the effect would be in the
longitudinal frequencies? And why would there be torsional movement in a
torqued string when the note was played? If the string is round, it seems to
me that it would act pretty much the same whether it was twisted or not. If
it was oval, and had a different modulus of elasticity horizontally and
vertically, it would surely make a difference if it was twisted.   


>Would torque affect the amplitude of longitudinal vibrations that might
>otherwise occur anyway?  Would lack of torque eliminate or minimize
>longitudinal vibrations?  Could it affect such vibrations in other
>ways?  I would be interested to hear some thoughts on this.
>
>Paul S. Larudee, RPT
>Richmond, CA


* While I don't have proof one way or the other, I doubt that one could
detect any difference. No one has ever reported any discernable difference
between strings installed with and without a slight twist. Then again, it
may be a matter of degree. Does the MOE and resultant partial structure of
music wire change if it's twisted enough? I'm thinking three or more turns
past what one would normally find installed in a piano. I don't know, but
anyone with an ETD and a piano in the shop could check it out. Even so, I
would expect any resulting changes to show up more in the transverse
partials than the longitudinals.

Does anyone else out there have anything more substantial?

 Ron