Truss Rod adjustment ?

BigLicks67 · November 2014

I'm getting what can be best described as a tinny sound from my top E and B strings. It sounds to me as if the string is slapping against the fret when played. The guitar is a Martin OM strung with 12's and has always had a pretty low action (i've never needed to adjust it since new).

My question is would a truss rod adjustment help here or is this just a quirk of the guitar?

Many thanks in advance for your learned replies.

ICBM · November 2014

Does it happen everywhere or only at specific frets? Or at all the lower frets?

It could be fret wear - that produces flat spots which cause a slightly 'sitar-y' tinniness. If it's not too serious it's easy to cure with a light fret dress.

Generally truss rods need tightening with time rather than loosening as the neck tends to pull forward slightly as the wood settles down, which would generally reduce a tendency to buzzing - but not always, and it could be climate-related too, especially at this time of year or if you've recently moved where the guitar is kept.

richardhomer · November 2014

Martins are rarely 'low' from the factory - though more recent ones are generally set lower they once were.

Have you checked the neck for straightness?

The correct way to do this, is capo the guitar at the first fret and (using your right hand) press the top and bottom Es down on to the fourteenth fret, where the neck joins the body. This should be done with the guitar in the playing position to eliminate the effect of gravity.

There should be a gap between the bottom of the strings and the 7th/8th fret of no more that the thickness of your top E. If the gap is less on the treble side than the bass side, that's ok.

If the strings appear to be touching frets all the way along, it is likely that the neck has a 'back bow' - effectively the headstock end is too far back. This will lower the action over the first few frets and create buzz. The truss rod needs to be loosened, if this is the case (turn counter-clockwise). Back off an eight of a turn and recheck.

If the neck is correctly adjusted, is is possible that the top has sunk due to being kept in too dry an atmosphere - though I would expect the neck to have developed a forward bow if this were the case.

If you hold a straight-edge across the lower bouts, it should 'rock' over the arch behind the bridge. If the top if perfectly flat, or concave, the guitar needs some moisture, using a guitar humidifier. There are several of these available - all are easy to use. A digital hygrometer is a useful thing to have either in the case, of the room the guitar is kept in.

Sorry to go on a bit - I hope these suggestions help.

BigLicks67 · November 2014

The guitar is 10 years old so there's a possibility of fret wear, but the sound does also occur on the open E.

Using the capo at 1st fret I'd say the neck looks pretty straight, particularly when compared to my Yamaha which has a distinct bow and a much higher action.

The guitar stays in it's case when not being played but not sure whether moisture/lack of is an issue, although I know central heating dries the atmosphere. Saying that I live in the North West and we are not short of moisture round here : >

I'll experiment with the truss rod adjustment at the weekend and see what happens.

richardhomer · November 2014

^ I live in the North West too - it's the drying effect of central heating which causes the problem - so cold wet places tend to be worse than warm, sunny ones.

The truss rod should only be adjusted if it needs to be. From what you say, the neck sounds to be okay.

You mentioned in that it only occurs on the open E. Do I take it from that, that the fretted notes are okay? If so, it sounds like the nut has worn too low and may need replacing.

Have you checked whether the top is slightly convex, as I suggested in my earlier post?

I'm a great believer that a player should be able to competently carry out basic adjustments but fiddling with a truss rod to see if it cures a problem which is unlikely to be caused by it isn't a good idea....

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Truss Rod adjustment ?

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