[CAUT] More on Single String Beats

[RicB]

Hi Folks

Several off list discussions with a few well known piano physics profs 
has recently confirmed a now long held suspicion that the idea that 
classic false beats or single string beats are caused by a loose pin is 
just plain way too simplistic and very far from complete.  In fact loose 
pins can only account for a contributing factor to the overall larger 
and holistic bridgepin / bridge / and soundboard termination area. As a 
consequence of this it should be expectable to find this kind of 
falsness in all registers of the piano, contrary to present popular 
belief that these are confined to the mid upper range of the piano.  
Closer examination of what the overtones of strings in all registers of 
the pianos does indeed reveal exactly this.  I am finding single string 
beating in all registers and these are of the sort that respond to the 
pressure of a screwdriver or similar tool to the side of the pin.  They 
are quieter and harder to discern the lower you get in the scale, 
probably because of the wealth of overtones and amplitudes of these that 
are present, but they are indeed and no doubt about it very present.  
 From A0 to C8 one can find this kind of single string beat popularly 
called the false beat.

One thing I find curious, tho I have not confirmed it yet... is that 
these beats seem to occur in range of 1500 hz upwards.  At least in the 
ones I've been able to identify in bass notes... they seem to convey a 
sense of being overtones in this range.

In all cases so far, the addition of mass to the strings front bridge 
pin, or an area very close to same has an impact on the speed of the 
beat.... and at some optimal degree of mass addition (or even 
subtraction perhaps) the beat disappears.

It has seemed to me for a long time that this whole area of sound 
problems needs quite a bit more close examination as to what really 
causes this single string beat.  And it also seems more and more evident 
to me that a cure, and one which bears with it other tone enhancement 
factors, lies somewhere in an <<optimal mass at the termination>> 
perspective as opposed to the idea that the pin simply needs to be tight 
enough.  Especially since loose pins can so often be absurdly present 
with no noticeable resultant single string beat.

Cheers
RicB