[CAUT] Hardness of termination vs string breakage (was Re: restrung D)

RicB ricb at pianostemmer.no
Tue Apr 24 03:28:39 MDT 2007


Hi Jim

Please do see if you can spor it up.  It wouldnt be the first time 
different ways of describing something seem in dissagreement more then 
they end up being :)

But to try and specify better the profile I've always used.  It is  a 
definite V form, not an U.  Flat contact area to the string with the 
edges of the profile cutting away from this surface area as opposed to 
rounded of.

Ted said something about the  rounded profile compensating for the 
string length change in the initial phase of the strings vibration...  
the quote was

    "A vibrating string is quite evidently being stretched at 
    amplitude . and the consequent lengthening is offset by the alternating 
    termination point caused by the deflection of the wire around the radius of the bar"

      

This is simply false, no disrespect intended.  If a rounded termination 
could effect any change in speaking length it would do so only in 
vibrational directions close to vertical, and this would result in 
differences between those directions in other directions... and this is 
the whole single string beat thing again.

There IS a difference in resultant inharmonicity caused by the two 
different profiles. The sharp/thin profile allows the string to flex 
more around the termination, and the round/wide causes more of a bend.  
In the former inharmonicity is lowered slightly.  Whether that is or 
isnt a desirable is another matter entirely.

Again.. read McMorrows stuff on this, and there is a lot of discussion 
surrounding this in the archives.

I'm off and running !

Cheers
RicB

      

    Hi Ric,

    I'll check. Maybe we're talking different things here. I think 2.5mm is
    the radius. Your .5mm profile might mean the same thing.(?) .5 radius
    would mean 1mm diameter. Am I thinking correctly?

    Have fun!

    Jim




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