plate reaction was Re: Pitch Raising to A440.......Or Not?

[JIMRPT@AOL.COM]

In a message dated 19/08/01 2:08:19 PM, RNossaman@KSCABLE.com writes:

<< then low later as the string slowly renders
through the bridge. 

Anyway, that's my take. >>

I would say your take is correct and take your take a little 
further....................

 A given string will not render past a front bridge pin until the tension 
above the pin is equal to, or larger than, the tension of the speaking length 
'plus' the friction gain at the pin 'and' across the bridge.  Additionally 
the string will not render past the rearward bridge pin until the tension of 
the speaking length is equal to, or larger than the sum of the friction gain 
of front pin 'plus' bridge 'plus' friction gain of the rear pin.........(if 
we add in aliquots then that friction gain would also have to be added to the 
total)
 Does the plate "flex" or "compress"...well yes without a doubt it does.... 
to some extent......... the question is 'which way'? With downbearing on the 
bridge the strings will have a tendency to pull upward on the plate...right? 
But since the hitch pin holds the string above, or on top of, the plate and 
the tension applied to the pin is off-center at the top surface of the 
plate....... the tendency of the string tension will be to pull/push the 
plate down...right?  So that being accepted........... the aggregate question 
then is whether these tendencies 'cancel' each other out...or does one 
overide the other?
  For the sake of question No. 1 let's assume that the bridge/soundboard does 
'not' flex....period.

 For question No. 2 we will add the 'flexibility' of the sounding board. Grey 
iron and steel wire are each relatively unaffected by changes in humidity 
whereas the soundboard is changed at a ratio determined by the available 
humidity and the cellular structure(s) of that particular board. This 
'humidity shift' changes from board to board and is much greater than any 
humidity change to wire or plate in any of the currently used 
formulations....................For the sake of the question let's suppose a 
static temperature and also suppose that a soundboard rises just enough to 
change speaking length tension but not enough to overcome "friction gain" at 
the front bridge pin. In this situation the pitch of the speaking length will 
rise, as will the pitch of the standing end of the string...except that 
because of equal tension and differing speaking lengths the pitch of the 
standing end will be proportionately higher than the speaking length...right?
 In this situation does the flexing/compressing of the plate follow the rise 
of the soundboard or does the plate remain static and realtively unaffected 
by this change?...............
Ponder points only. :-)
Jim Bryant (FL)