Strings on Duplex

[James Ellis]

Wim,

I can help you out here.  Your customer's contention that you ruined her
piano because each duplex bar does not have three strings on it is utter
nonsense.  If you did "ruin" it, that's not the reason.  To fully make
sense of this, I would need to give you an essay on the history, theories,
developments, and fallacies of the duplex, but there simply is not space
for that here.  At one time, Del Fandrich and I were going to do an article
on this, but the idea got sidetracked.  We might still do it at some time.
But I'll get to the point.

The rear duplex is very different from the front duplex.  The notion that
energy will transfer across the bridge, single string speaking length to
single tail, is nonsense.  It doesn't, and it can't.  That's because of the
way the strings terminate at the bridge.  Energy does transfer across the
bridge from whole groups of speaking lengths to whole groups of tails by
the vibration of the bridge itself, but not from single string to single
tail.  Contrary to common belief, it doesn't really matter if a single tail
is on the proper duplex bar or not.

What DOES MATTER is that the string tail either firmly rides on the bar, or
that it completely clears it.  If it just barely touches the bar, you will
get all sorts of loud zings, rattles, and buzzes.  I have seen a few cases
of this on brand new S&S pianos.  I even wrote S&S NY about it a few years
ago, but as I expected, never received a reply.

Exactly how you will explain this to your customer, I don't know.  I don't
think you will change her mind.  Human psychology comes into play here.
The next time your restring a piano, just make sure all three strings ride
on the proper duplex bars all the way.  That way, it will look right,
despite the fact that it won't really make any difference.

What DOES make a big difference is the sum total length of a whole group of
string tails, especially in the bass and tenor, because that affects the
compliance of the soundboard in that area.  In the high treble, you can get
away with very short tails, because the board is narrow and stiff up there
anyway.  It needs to be, because you want to accentuate the high
frequencies of the string vibrations and suppress the thuds of the striking
hammers.

Good luck,  Jim Ellis