[CAUT] Re: D with a ghost

[James Ellis]

I posted that item for the benefit of those who might also be encountering
the ghosting problem.  

Wim:  I had you in mind when I wrote it.  

Eric:  I'm not surprised at all.  In fact, I would be surprised if it did
not happen.

Don:  You are absolutely correct about the sustain, and about one set of
strings taking energy from another set of strings if the tuning is just
right. It has to do with resonance, phase angles, and how much mutual
coupling there is between them.  But I disagree on one point.  Lightly
muting the C-4 rear duplex is not going to reduce the sustain of the
speaking length of C#-6.  It will improve it, because it will get rid of
the resonance between the two that is robbing the C#-6 of its output to
excite the C-4 duplex.  There was obviously enough coupling and critical
tuning here to make it happen, despite the fact that the strings were two
octaves apart on the bridge.  We see this all the time in resonant
circuits, whether they are electrical or mechanical.

Ron:  Pitchlock is not going to help the situation I describe.  There is
not that much mass in those little clips, and we aren't trying to lock two
strings of a unison together.  It might shift the problem to a different
set of strings, but that's about all.

John:  It's the same thing I told Ron:  I'm talking about the rear duplex,
not the front.  The front duplex is something else entirely.

Eric has the right idea.  Just mute off the offending rear duplex - the
rear - not the front.  Do that to the front, and you will make the note
dull by damping the higher partials that bleed over the capo bar.

My philosophy is:  Keep all the important partials in the speaking lengths
where they belong, but there are those who disagree with me.

Jim Ellis