False Beats

[Ron Nossaman]

>Ron Overs... you make a great case for the offset angle, I do have one 
>quiestion relating to this tho.. the necessity for a particular degree of 
>sidebearing to avoid this kind of falseness... is this because of the use of 
>bridge pins to secure the string to the bridge to begin with ? Or is it (the 
>side bearing)  necessary in the effective transmision of string vibration to 
>the bride, hence dictating the use of the bridge pin configuration ?

Wrong Ron, I'm the one on the left, but I'll bite. The side bearing,
stagger, offset, or whatever you want to call it (Uncle Fred?) is purely to
provide enough angular deflection to make use of the string tension that's
going to have to be there in any case, to provide a reasonably secure
string termination at the bridge pin. It matters not a whit what direction
it takes, from a termination standpoint, as long as the termination is
minimally solid in all directions, and the mounting system is supportable
by the available parts. More on that below.  


>I think back to that wreck of a piano I saw a while back with the brass 
>clamps.. not a good example to judge by for sure... but the sound there 
>was... well.. better for sure then the surrounding area on the bridge... 
>Also one thinks of the bridge aggraffe system.. I have never had a chance to 
>check one of these out so I dont know how they sound.. yet as some were in 
>production for quite some time I suppose the solution was workable from an 
>acoustic point of view. These would indicate (to me anyways) that side 
>bearing in itself would not necessarilly be essential.
>
>If on the otherhand, these configurations have inherent falsness of this 
>type, and the employment of the appropriate amount of side bearing is the 
>way to get around it, then I sure would like to know a bit more about the 
>mechanics involved.

It's every bit as simple as it looks. Greater bearing angle = greater
pressure from a given tension = more solid termination. Pin inclination
angle clamps the string to the bridge. The greater the angle, the more
positive the clamp. The traditional bridge pinning system is still used, as
far as I know, for the same reason it was developed in the first place.
It's easy to understand, easy to produce without expensive machinery and
great quantities of labor, easily modified in production if one wishes to
change angles in experimentation or to attempt to cure perceived problems,
it provides the greatest return in termination efficiency for production
cost and labor expended (again, as far as I know), and it's in the public
domain. The limits to the process are inherent in the strength of the wood
in the bridge. Excessive side bearing angles, and/or pin inclination angles
can put undue strain on the bridge material without effectively improving
the termination quality. Like just about everything else we touch, there's
a trade off, and therefore an optimal balance between function and cost -
be it monetary or damage potential. Theory and practicality have to meet in
the middle somewhere to avoid becoming one of those stories about the
fabulous old - insert icon of choice - that was wonderful beyond belief,
and cheaper than anything, but isn't available any longer because they
tended to self destruct and take large portions of the surrounding
countryside with them. Or, they were very good, but too expensive, or
awfully expensive for the slight evidence of improvement over the generic
product. About the only way to duck this natural law of conservation of
performance is to cut costs to a degree that is perceived as being
proportionally less than the accompanying drop in performance, making up
the difference with advertising. This works great in the short run, but
eventually gets back to the "What ever happened to..." Since changing
stagger offset angles, pin inclination angles and diameters doesn't really
cost much of anything in the grand scheme of things, and it ends up working
pretty well, and for such a simple system, it's not bad.   



>I have a similar old Bechstein.. a 9 footer... horrible falsness.. yet I 
>suspect we are talking about falsness related to other problem areas then 
>the bridge pin alone.. And in any case on mine there is no capo bar.. 
>(common to Bechstein ??) only agraffes. Here I wonder if things like lack of 
>crown / insufficient downbearing, worn agraffes, old strings, etc are the 
>major problems. In anycase the kinda falsness I hear on this piano is 
>entirely different then that I hear from the Petrof piano I describe when 
>starting this thread. Here the falseness is very unclear.. wangy, string 
>noise-ish, long unstable meeeowww-ish like.

Yep, that's different stuff, starting with duplex noises, through mass
loading bridges, to ??????? Possibly even evil spirits. The SAT II doesn't
have all of them, you know.


Ron N