bridges/seating

[Ron Nossaman]

At 05:36 PM 4/6/97 -0400, you wrote:
>Since I've read the first post on this subject, I've been wondering. If the
>small indentation the string makes in the bridge can reduce sustain, is it=
 a
>good thing to tap strings on the bridge to get rid of false beats? It seems
>to me that by tapping the strings, we would be driving the strings in the
>bridge. Would it be better just to tap the bridge pin? Also, is it the
>sanding that improves the sustain or could it be only the renotching?
>
>I'm curious to find out what you all think.
>
>Marcel Carey, RPT
>Sherbrooke, QC
>




NOTICE: The following is my OPINION (based on experience and logic), not to=
 be confused with, and modifyable ONLY by, FACT (or gooder logic).



Hi Marcel,=20

    If the grooves are deep, the string termination point will be farther=
 forward on the bridge than on the bridge pin. That could affect sustain.=
 Other that, I don't see how.=20

As far as tapping strings on the bridge, I think it's not a good practice. I=
 have heard and read many times that strings will ride up on bridge pins and=
 need to be "seated" to stop false beats. This is contrary to the laws of=
 physics as I know them. I don't think it's possible for a string, with=
 measurable positive bearing, to ride up a pin (against tension), slanted to=
 force the string down on the bridge (against side bearing), and stay there=
 until someone knocks it back down where it belongs. It's just a case of=
 techs misinterpreting what they think they see and hear. The string noise=
 most likely comes from a loose bridge pin. Isolate a beating string with=
 mutes, play the note, and press a screwdriver against the front bridge pin=
 on the side opposite where the string touches. The beat will probably go=
 away, returning when you remove the pressure. Tapping the string down will=
 temporarily clear the beat up by wedging the string down into the groove in=
 the bridge, making it deeper in the process, as it springs the loose bridge=
 pin back against the side of the hole until the movement stops, further=
 elongating the top of the hole. The noise stops and the assumption is that=
 we have seated the string back down on the bridge where it belongs, when=
 all we've done is affected a temporary "false positive" result at the cost=
 of long term damage to the=20bridge. The problem will be back with the next=
 humidity cycle. Driving the bridge pin deeper is a much better approach,=
 (gently) but won't work in many cases. The real problem is the loose bridge=
 pin and can be cleared up by epoxying (or CA) them in solidly. This isn't a=
 casual field repair to be done with a normal tuning. It requires lowering=
 tension, disengaging strings from the bridges, epoxying, curing,=
 re-assembly, and tuning. It's time consuming, expensive, and traumatic to=
 most folks. That's why most techs continue to take the easy out and "seat"=
 the strings as they shorten the long term service life of the instrument.=
 Sometimes you don't have a choice in a concert situation where you have to=
 make it clean, and right now. Just remember to consider seating strings on=
 bridges to be an emergency only procedure, not a daily practice.

To all: If anyone has contrary enlightenment, I'd be pleased to hear it.=
 Rants will be deleted immediately. End of opinion.


 Ron Nossaman