[CAUT] Re: Tuning the backlength

Ric Brekne ricbrek@broadpark.no
Tue, 06 Dec 2005 09:15:33 +0100


Hi Jim

A couple headscratchers I have about this stance is that if you pluck an 
undamped strings backlength firmly then the speaking lengths fundemental 
is excited.  Not nearly as much as with the front duplex to be sure, but 
it does indeed get started. If you pluck the back length of neighboring 
strings for that same undamped string... then nothing... at least 
nothing audible. 

Then the other point that I wonder about is how the two lengths of a 
string interact with the brigde.  When the bridge vibrates, the two 
lengths can either support one anothers efforts to keep the thing 
vibrating, or work against each other yes ?  If the two vibrate in close 
enough harmonic coincidence with one another then energy transfer to the 
bridge should be made a bit more efficient. Doesnt that mean a 
corresponding lessening of sustain and increase of power ?

I'll agree that simple aural impressions alone are not sufficient to 
substantiate any claim. On the other hand, when seemingly vast amount of 
technicians have these same impressions, one has to wonder at the very 
least if there is truth to them. 

Its a very curious issue to be sure. One that deserves a bit of hard 
science... and probably wont get much.

Cheers
RicB

-------------------
Jim Ellis writes:

The question remains:  Do the transverse modes of individual string tails
couple across the bridge to those of individual string speaking lengths?  I
say they don't, unless the bridge termination is faulty.  They DO couple to
be sure, but over whole sections of the bridge - the closer the tails to
the speaking lengths, the more the coupling.  If anyone can send me hard
measured data to prove me wrong - not just aural impressions - I'll change
my stand in a heart-beat, but until then, I'll maintain it.

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