SAT & wild strings

[Jim]

Dear Ed:

As you probably already know, the wild string effect is produced by a string
vibrating at two frequencies at once.  For example, when a string has in-
dented the bridge out in front of the bridge pin line, the string is essent-
ially shorter in its downward excursion than when it is up and bearing only
on the bridge pin. A similar thing happens when you have a loose bridge pin.
It can also happen when the V-bar is flat and the string cycles over the two
edges of the flat.

As these two frequencies bounce off the walls nearby, they
are in conflict at the point of the mic.  You can move the SAT around from one
point to another to get a stronger emphasis in the display for one or the other
of the two frequencies.  If one of the frequencies is at a null point at the
mic due to bouncing off opposite walls and meeting at the mic in opposite
phase, then you see only one indication in the display.  If both frequencies
meet equally strong or away from their null points, the display will
oscillate back and forth between the two frequencies at the speed of their
difference beat.  At this point, you can run the cents up to stop the display
of the higher frequency or run the cents down to stop the lower frequency
display.  You will still be able to see the indication of the other frequency,
but it will be moving.

If I am ever confused as to which frequency I want to tune, I can tune one
and then play a 17th below and compare with the neighbor's speeds.  I mainly
want to use the one which fits with the neighbors best, but sometimes will
settle for the one which is the loudest.

Jim Coleman, Sr.