=?ISO-8859-1?Q?Re:_Bridge_Seating_(was_Re:_Where_to_notch_a_bridge, &_relative_effects_?????_(Advice_sought)?=

Ric Brekne ricbrek at broadpark.no
Fri Sep 8 02:41:23 MDT 2006


Hi David, others.

Exactly ! I see no reason to get into a state of denial about the 
usefulness and necessity of string seating.  I do see the point about 
when it becomes destructive.  But that does not touch on when it is 
appropriate and is in reality a different subject matter. 

    Let me see if I'm clear on this...the front edge of the notch has
    been crushed by humidity increases and decreases on this brand new
    Yamaha grand piano.   That is why when I tap the string it drops?  
    SIGH...

    David Ilvedson, RPT
    Pacifica, CA  94044

This is boils down to rather simple geometry. Forget the string for a 
moment.  If you think of the front termination, hitch pin (or aliquot 
termination in the case) and the high spot of the bridge as a simple 
triangle and can measure that the entire surface of the bridge pin is as 
high or above the line drawn down from the high spot of the bridge to 
the front termination.... (and the same to the back length termination) 
then there is a positive bearing situation for the string to seat on.  
If the string in spite of this situation is for whatever reasons off the 
surface of the bridge.. then it needs seating. 

If on the other hand there is some length of the bridge surface below 
this line between the high spot of the bridge and the front termination, 
then ordinary seating will be at best a very temporary improvement and 
at worst a further detriment to the condition.  

If one can lower the high spot of the bridge by sanding the entire plane 
and still be able to measure positive down bearing afterwards  alleviate 
a localized negative bearing problem... then by all means do so either 
by sanding or by light taping at the high spot of the bridge. 

Whether (and why) the string is seated properly on a bridge surface that 
provides a positive bearing situation or not is a completely different 
subject matter then whether or not there is indeed a bridge surface that 
meets that requirement in the first place.

Cheers
RicB





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