Ghosts of impedance past, and yet to come

[Richard Brekne]

Hi Ron.. I also have noticed this. Ever since we got into that string
coupling discussion a while ago I have been watching what RCT and Tunelab
show. I can only say that my own observations are identical to the ones you
describe below. Even to the point of likeing the sound of the notes that
rised in pitch a bit when the second and third strings are coupled. I have
also found occassionally that when a second string is coupled the pitch may
rise or it may fall a bit, but when the third string is coupled in it goes
the other direction.

Also thinking perhaps I was just a bit off on one side or the other pitch
wise with the second or third string, I would double check what RCT /
Tunelab had to say about each individual string. Couldnt find any "mistake"
on my part to account for it. I aggree that sometimes they almost seem to
be steerable.

Kinda shoots the tomatoes out of the present "string coupling " theory tho
dont it ??



Ron Nossaman wrote:
> 
> Hi Gang,
> Anyone remember my fevered speculations about the possibilities of the
> reported pitch drop from a single string to a two or three string unison
> possibly being related to the soundboard/string impedance match/mismatch?
> Well, it just got stranger.
> 
> Tuning the Kimball grand I'm finishing up, I set Tunelab going so I could
> watch what a unison's pitch did as I progressed. I spent most of my time in
> the top half of the scale. Some unisons dropped slightly, some stayed the
> same, and some climbed in pitch as the second and third strings tuned in.
> It was about an even three way split on probability, with no obvious order
> or grouping as to position in the scale. The changes in the timing of the
> attack pitch climb and drop back to dwell pitch were every bit as erratic
> as the dwell pitch change. Some unisons that hadn't changed as the second
> and third string tuned in, tended to climb slightly in pitch in decay. Some
> dropped.
> 
> Thinking I might have some control of the process by where I centered the
> tuning of that second string, I played with it a bit within that area just
> sharp or flat of dead-on to the first string - where you can wooly up the
> attack a little without leaving a noticeable roll in the unison. Some
> unisons seemed to be slightly steerable, some not. My favorites were the
> unisons that went sharp as the second string tuned in, even when the second
> string was still a beat low.
> 
> In most cases, the addition of the third string took the climbers a little
> higher, the droppers a little lower, and left the non changers non changed.
> The only reasonably dependable effect I found was that the attack phase
> pitch climb  tended to shorten in duration with the addition of each
> string. It was interesting watching the attack phase of the unisons that
> climbed in pitch. The single string envelope profiled about like that of
> any other single string. Adding the second string, the attack pitch climb
> seemed to be less than with the single string, but rose to maximum dwell
> pitch in a second or so.
> 
> So far, no answers, just more and different effects than others are
> reporting. I'll tape off the back scale and play with it some more this
> weekend. That will probably just add another layer of unaccountable
> weirdness, but I might get lucky too.
> 
> Later,
> Ron N

-- 
Richard Brekne
Associate PTG, N.P.T.F.
Bergen, Norway