Seating strings

[Phillip Ford]

>Hi Phil
>
>...It is simply assumed that the strings force upwards for even a hard 
>blow is not enough to contribute to the string moving upwards on the pin. 
>I dont know myself how much of a yank there is there... but it has to be 
>pretty signifiacant to get the mass that the soundboard is along with the 
>string plane to vibrate in a large enough amplitude to create the volume 
>of sound we hear.  I did do a cute little experiement a while back... put 
>a penny on the string just at the bridge pin and whack the key.
>Dont get in the way of the penny... :)

Hi Ric,

Yes, that is my assumption.  But I don't have any experimental evidence to 
back it up.  The force or the movement may be a lot greater than I imagine.

>Another moment that bothers me which I see no one looking at is the fact 
>that the string is forced into an unatural curve across the bridge surface 
>to begin with. A string pushed up by a flat surface the width of a bridge 
>will not (without bridge pins) lay perfectly flat on that surface. It will 
>tend to bend around the surface being highest in the middle.

Which may be one of the reasons that the cap gets crushed at the notch.
Perhaps the top of the bridge should be curved to accomodate this.

>   The bridge pins force the string to flatten out, creating essentially 
> two fulcrum points where the string contacts the bridge. Which forces are 
> doing what in this regard I dont know... but it would seem to me that 
> since the string wont be comfortable just laying flat as it were.

And if these fulcrum points are actually slightly back from the edge of the 
notch because of the way the pins are holding down the string, then the up 
and down movement of the string would be tending to crush the edge of the 
notch, especially if the string movement really is violent.  Perhaps the 
idea of notching slightly back from the pin is a good one.  I wonder if 
long term this type of notching tends to exhibit less false beat development.

>A third point which relates to the friction by the pins that seems totally 
>over looked is that these also are vibrating in their own fashion.
 
I don't think it's overlooked.  I think this is what Ron, and maybe Roger, are
saying.  Because the string is not firmly down on the bridge at the pin, the pin
is flagpoling, which is causing the false beat, by some mechanism which I don't
think I've seen described.

>For that matter the whole assembly is moving around, components phasing in and 
>out .... all in all a pretty complicated picture.

Agreed.

>
>Seems to me that  carefull observation clearly reveals that strings do 
>indeed somehow climb up these pins.

I also think we may need to clarify what we mean by climbing the pin.  Are 
you talking about the whole string lifting itself off of the bridge cap or 
the portion of the string at the notch not wanting to stay down in the 
groove that tends to form with time?

>   Just how remains perhaps a mystery.
>I sure would like to hear more about Maninnos video tho.... :)
>
>Cheers
>RicB

Me too.  I wonder if he'll have them at the upcoming convention?

Phil Ford