Seating/false beats

[Ron Nossaman]

Hi John, can I play?


At 03:04 PM 4/16/97 -0500, you wrote:
>Hi all!
>
>Geeze... A guy takes a few days off the list to take care of his new kid
>and everyone beats him to the answers!
>

New kid! We'd better get this thread wrapped up before cumulative sleep deprivation takes you out altogether. <G>


>Thanks to all for their input on this issue.  Its been fun to see a
>discussion move toward consensus as people on the list put their
>considerable talents toward a problem.
>This thread - and the one about optimizing repetition remind me why this
>list is the best resource around for continuing education.  Keep it up
>folks!

Ditto. Having a ball. This thing has bothered me for twenty years but I never had the chance, or took the trouble, to try to get enough different brain cells together to formulate a rational explanation for what I thought I knew. Now I know that I didn't
know what I thought I knew when we started, you know?


>
>This whole issue has made me want to look at the bridge pin/bridge system
>and how it responds when a note is played.  Has anybody come up with a
>fairly complete model for this.  If not, can we discuss how such a model
>might be designed an tested?
>
>Some things I have in mind:
>
>1. What does the b. pin look like at the top vs. the bottom as it vibrates.
>and how,
>     exactly, does this change with a slightly loose pin


Guess on 1: As the hole enlarges over time with seasonal humidity swings and the bridge top saws up and down the pin, the side bearing would lever the pin at the top. This would spring the pin in a slight arc as the top of the hole wore faster then the ar
ea half way down while the bottom didn't wear at all (hardly). I would think a loose pin flagpoles with side excursion of the string, being forced against the "back" wall of the hole when the string swings toward it, straightening and springing back towar
d the center of the hole as the string swings away and the side bearing lessons enough for the pin tension to overcome it a bit. This would make the effective horizontal speaking length much longer than the vertical. Result, a beat rate corresponding to t
he difference in the two speaking lengths in the same string. Oh, the bottom of the pin probably isn't moving in the bridge at all.


>2. How does the above contrast with the bridge material directly adjacent
>to the pin.

It's going up and down with the rest of the bridge according to the vertical portion of string motion. (simplistic, probably much more to this one)

>3. How does the model change with the introduction of foreign material
>around the
>    pin (i.e. epoxy or CA)


CA or epoxy would solidify the wood around the pin for it's entire length. This should severely inhibit the ability of the wood in the area immediately around the pin to both absorb moisture, and change dimension as a result of moisture transfer. Sorry, s
tarting to sound like a Government employee. Anyway, if it doesn't absorb, it won't move and the hole won't get scrubbed oval. This wouldn't be an absolute, but the pins should stay tighter, and the tunings cleaner, longer as a result.


>
>Just meant to be a start.  You fill in the rest.
>
>John McKone, RPT
>St. louis Park, Minnesota
>(612) 280-8375
>mckonejw@skypoint.com
>


Thanks for the chance to play. All further enlightenment cheerfully embraced.

Regards,  Ron Nossaman