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It's that time of year... temperatures and humidity bouncing all over the place. And your guitar that is always in tune and never any fret buzz, suddenly all out of whack with frets buzzing like a chainsaw. So what ya gonna do? Fret buzz can be caused by several things, so before we start cranking away on the truss rod or grinding away on your frets, let's diagnose the problem.
First let's do a quick check on your action. At the first fret a thin pick (.46mm) should slide between the strings and fret without raising the string much. Check each string separately by holding the other strings up. At the 12th fret the strings should have 1/8" or so, depending on your desired action.
Now let's check the relief (curvature of the neck) by fretting the low E string at the first and fret where the neck meets the body. Three hands or a capo make this easier. While doing that check the distance between the fret and string midpoint between those points (usually 7thy-9th fret). There should be a tiny space...thickness of a business card. Repeat for the high E string side.
If there is no space, you may have found your problem... negative relief (neck bowed upwards). It is common for necks to shift a bit, particularly when there are changes in humidity. You can adjust this yourself by turning the truss rod counter-clockwise 1/4 turn. Recheck and repeat as necessary.
If your action is in the ball park and your relief OK, let's move on to the frets. First, which strings are buzzing? Do they buzz played open or just when fretted? Which fret(s) do you get the buzzing? Does the buzzing go away when fretting further up the neck? Sight down the fretboard from both ends to see if there are obvious bumps or dips.
If the strings buzz only on open strings it suggests that nut slot may be cut too deep for that string.
If you can isolate the buzz to particular frets, use a credit card as a straight-edge, span three frets at a time and see if you can get it to rock back and forth. If it rocks, you've found the culprit. Move up and down to determine if it is a high or low fret. Do this at each string. Is the fret loose or damaged? Sometimes they can be tapped down.
If you have a high fret, it can usually be leveled and re-crowned. If you have a low fret, either a whole section of frets need to be leveled or that fret replaced.
If you can't find the problem, if you have questions, or you get to a point where you don't want to tackle it yourself, give me a call.