[pianotech] Additional Information Regarding False Beats

[Richard Brekne]

Hi David

    Ric,

    Are you saying that inserting a brass bushing (what is that?  like a
    pin?) under the string in the middle of the bridge will never cause
    a false beat or that sometimes it never causes a false beat?   That
    replacing a bridge pin on a string that is clean always stays clean
    even if the new pin is smaller and loose? 

    David Ilvedson, RPT
    Pacifica, CA  94044


"Never" is a very big word, as is "Always":)  So of course I wont say 
this or that either "always" or "never" happens. I do know a fair deal 
about the discipline of statistics however and can use it reasonably 
well enough to confirm, validate, (or not) claims like the "loose pin 
causes false beats" theory.  And after some 50 experiments of various 
ways simulating the loose pin condition I find it impossible to confirm 
the cause/effect relationship claimed and indeed see more statistical 
evidence to reject it then anything else.

To answer your query about the brass bushing. Yes it could be a center 
pin (and I have used those as well a few times for this), but really 
anything that will raise the string level over the bridge surface 
leaving the front half of the string more or less floating in air held 
only in place by the front bridge pin. 2 mm height ought to more then be 
adequate to ascertain the assumed flag poling effect that is supposed to 
cause false beats.  If you do this on say 100 strings, you need to 
observe enough positive returns on your hypothesis for it to be 
validated.  Under this percent there is a grey area where you can 
neither validate or discount it, and at some point you have enough 
negative returns to reject the hypothesis. My experiments lean pretty 
heavily towards rejection.

You can also take false beating strings and subject them to the same 
kinds of experiments and find similar random results.  An annoying (for 
the theory) degree of false beating strings actually get cleaned up when 
raising them thus or inserting a very loose pin.

I cant see how this points to anything else then that there is very good 
grounds for suspecting that something else is primarily at work in the 
occurrence of classic false beat. The fact that the addition of CA, 
epoxy, various lacquers etc to the wood so often results in a lessening 
of falseness does not in itself support the loose pin idea.  It only 
shows a connection between the addition of these substances to the wood 
of the bridge and the occurrence of false beats. It does not follow from 
this fact exactly what the cause/effect relationship is one way or the 
other.  Its interesting to note that this same addition of these 
substances has essentially the same "cleaning" up effect on strings 
where I have purposely also introduced an undersized bridge pin. All 
this points me in the direction of looking closer at the role the wood 
in the area of the bridge surrounding the bridge pin itself has to play 
in all this and away from the idea that it is a flag poling pin that is 
at fault.

I know of course this is at odds with the popular notion at present.... 
but the data  in front of me is just plain to difficult to ignore.

Cheers
RicB