Mechanics of fret buzzing on a straight neck, and a relieved one

river251

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I received a new guitar, and want to set it up. I have read many threads and watched many videos on relief and action but still can not visualize what happens as a string is fretted. I will leave discussions about relief for another thread.

Looked at one way, with a straight unrelieved neck, it doesn't seem possible that the ellipse of the standing wave of a vibrating string can intersect a straight line along the tops of the frets, because that straight line must form a tangent to the curve of the ellipse at the fret. It is not possible that string oscillation could hit against a fret causing buzz, it the neck and frets are levelled.

Looked at another way, it is possible to pluck the string hard enough so the ellipse is wide enough (and thus curved enough--in the limit, it would become a semi-circle) so that a straight line along the frets IS intersected by the curve of the ellipse. As curvature increases, the angle between a tangent to the arc at the fret and a line from the fret to the bridge must increase.

So am I right that even if the neck (along tops of frets) is perfectly straight, you can still get fret buzz on fretted strings, or not?

Now, add in .008" of relief at the 8th fret.

I can not for the life of me visualize or reason through how this increases or decreases the string height at which this straigh-neck buzzing will occur.

??
 

cmjohnson

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Play an open string. The point of maximum string excursion is over the 12th fret. Relief is necessary to accomodate for the wider excursion of the string toward its middle area. For any fret you note at, the point of maximum string excursion is 12 frets higher.

35 years experience as a guitar tech and luthier. Believe me, a little bit of relief really matters, on some guitars more than others, but never is a dead straight neck the answer for the lowest possible action.
 

SWIM

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You wanna do what with your strings now?
 


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