[CAUT] String Coupling / SB and Bridge stiffness

[Richard Brekne]

Hi... no bites on this so I thought I might try phrasing it a different 
way and see if I could get any feedback. 

If the string terminations were infinitely stiff, then there would be no 
mechanism for string coupling .... yes ? You could in theory have a 
piano unison, excite the strings in the usual way with the hammer.... 
but the infinite stiff terminations would not allow for any coupling, 
there by the strings would each vibrate completely independent of one 
another.  Ok.... so add a set of non infinitely stiff bridge pins and 
leave everything else about the terminations infinitely stiff. You still 
have the same situation, tho the bridge pins become some form or another 
of an extension of the string.  Perhaps this scenario would open for 
false beats on individual strings at best, but there is still no 
mechanism for the three strings to couple given the infinite resistance 
to vibration by the bridge itself.  So no pitch drop due to coupling is 
possible as no coupling is possible to begin with.  Yes ??... So at some 
point the bridge becomes non-stiff enough to allow for this coupling.  
And the more non-stiff the bridges becomes... the greater the ability 
for the strings to couple, hence the greater their influence on each 
other... and hence the more evident (greater degree ?) of pitch drop.... 
Or what ?

Cheers
RicB

    Got to thinking abit about string coupling and the mechanisms that
    are at work that account for the pitch drop and got to wondering if
    it is viable to think of the degree of pitch drop when 2 and 3
    strings are coupled in on a unison as an indicator of  SB/bridge
    stiffness at any given note.

    Or... is this another one of my rabbit holes ?

    Cheers
    RicB