[CAUT] pre-stretching new string?

[Richard Brekne]

Hi Scott

I dont think anyone would go so far as to say the board is not a major 
contributing factor.  Its just that the idea that a change in the 
vertical displacement of the string by the board / bridge and board 
assembly can account for much of a change.

I look at some obvious consequences of such changes... and these rule 
out either by virtue of physical realities or by what we observe that 
vertical displacement changes can account for much.  That basically 
leaves segment length changes which when accompanying change in tension 
is calculated become interesting. Even these tho have to add up with 
what we observe.

For example... we see that major changes are happening to the long tenor 
unwound strings.  So far... there is nothing I've seen put forward by 
anyone that can account for these changes.  It is stated that the low 
tension on these wires cause a far greater response to similar changes 
relative to wire under higher tension.  But you can calculate change in 
tension for change in segment lengths... and you need a combination of 
all segments changing lengths pretty significantly to account for the 
observed change in pitch.

One also has to account for why unisons consistently display non uniform 
change in  pitch to climatic changes... and do so in such symmetric fashion.

There is lots we dont really have figured out here... but a strictly 
vertical displacement just doesnt seem likely.  A  monochord experiment 
with an adjustable bridge height deflection will underline that nicely 
for you.

Cheers
RicB


    Ok, I get it. Thanks for the clarification.

    Maybe you guys are right, but it seems counterintuitive to me that
    the board
    is not a major contributing factor due to it's size and the fact
    that it is
    captured in the rim and has rise and fall (or try too).

    Is it possible that tension could increase in response to the upward
    force
    while also containing the upward movement, or is that impossible?

    Scott

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