[CAUT] more front duplex fun

[Ric Brekne]

Hi folks


I have a very easy little experiment I would like as many of you as possible to play with me.  Ran into it today after having fooled around a bit with various things this past month.

Take a good thick bridge pin and insert it in the middle of the front duplex between two strings of a unison in the highest octave.  Play the note muting the one string that doesnt have the pin touching its front duplex segement  so that only the two that have it sound.  Listen closely to the pitch(s) that are sounded.  Now move the pin slightly  into various positions close to half way between the capo and counterbearing.

Its really quite weird... the secondary pitch that comes very  clearly through is extremly tuneable by the position of the pin, and it is lower then the fundemental of the speaking length... by quite a bit really.  Put in the exact middle of  A7 on a Steinway C I was checking this out with today, a clear 5th below the fundemental of A6 was sounding.  I have no explanation as to how this sound comes about... but it was unmistakable.

The neat thing you could do tho was to move the pin very close to the counter bearing point.   Especially on the highest notes...from around f7 upwards.... sustain and clarity were markedly improved if you got the pin just right.  Insertion of a second bridge pin to couple the third string into the picture seemed to require a slight offsett in position to find the <<best>> overall effect for the entire unison.

Strikes me that this has some obvious implications for potential alternative approaches to the front duplex length.  It also re-enforces another thougth I've been having for quite some time now.  That the length of the front duplex, and probably also the angle of the offset up to the counterbearing have little or nothing at all to do with energy loss across the capo.  These rather more likely only deal with what happens to that energy.  Either one damps it.... or attempts to utilize it in some fashion. But either way the amount of energy that leaks across the capo is probably  not affected much by  various types of front terminations.

Cheers
RicB