String coupling.

[Ron Nossaman]

>Has anyone considered that this area of the soundboard may be the most
>flexible and that the single string of a unison does not have as much
>effect on the bridge as all three pulling the bridge up and down
>together.  
----------------
>Larry Messerly

Hi Larry,
But the killer octave probably isn't the most flexible part of the board.
It's probably going to be more flexible in the mid - low tenor and bass
area, even in the worst case killer octave you ever heard. No, a single
string won't have as much active affect on the bridge as three, but even
with two strings muted off, they are still coupled to the active string
through the bridge and acting as dampers to the active string's motion.
When they are free to speak along with the unison is when you would get
partials mismatches, or whatever it proves to be. Consider that in one pass
of my trial samplings, with the duplexes taped off, the pitch drop didn't
happen with all three strings in the unison speaking, through the entire
octave I tested. That's a smack in the forehead that got my attention and I
intend to look for explanations among the dumbest and simplest
possibilities first before I get into the stuff that requires brains and
equipment. I've found and downloaded some spectrum analyses software, so
maybe I'll have something with which I can look a little deeper - if I
happened to accidentally get one of the one out of twenty of anything that
actually works and does something useful. I'll install a few on my laptop
and play a little.
Ron N