One of the most common problems of any string instrument is a string buzz. There are a lot of reasons that may cause it, as well as hints that help (or impede) solving these problems. Let’s sort it out with the help of T00DEEPBLUE, Captaincranky, Laudiesdad, SilentDeftone, jj1565, stringvester, yope, Paleo Pete and K33nbl4d3.
1. In case of one string buzz on exact fret it’s probably being caused by the next fret being high in the buzzing string area. A high fret can be high on any portion of it, such that it only affects one string. Also you can use a small piece of paper flat against the fretboard see if you can feel where the string might be touching the board.
2. If the buzz arises right after string change, keep in mind, that old strings need more tension than new strings to bring them up to full pitch. It is possible that the buzzing might diminish a bit during the coming days.
Have you stretched the new strings yet? Have you put the plastic saddle back in the bridge? It's a fair question, some people forget. And make sure the old & new string sets are the same gauge. Size is more important than brand.
3. One thing that you need to understand is that when you change one thing on a guitar, such as going to lighter strings, everything else changes. Going from a set of 10-46 down to 9-42 strings for example, will lessen the tension on the neck as there is less pressure exerted. This will cause the neck to move back, decreasing the neck relief. Lowering the action (hence, buzz) and screwing up the intonation. My best advice is to take it to a tech and have it set up with the gauge and brand of string you want to use and then stick with that brand and gauge. If you were to change brand of strings (even using the same gauge) this can happen. You can learn to do a set up yourself with a few tools, but without a strobe tuner, you will never get the tone right. And, as strobes are expensive, you may be better off to have a tech do this once or twice a year as needed.
4. The string may be a little bit too thin for the space in the nut and/or the bridge, and it's rattling there.
5. If the nut is cut too deep on a string, a good stopgap is to cut a very thin strip of tinfoil (same width as nut i.e. about 6mm). Make the strip about 5 cm long and fold it 3+ times. Lift the string out after loosening. Place the tinfoil over the groove, place the string over the tinfoil and let it fold it into the nut as it settles back in. Works as a temporary solution.
6. If the string isn’t touching anything, and its buzzing from the nut, then rub a pencil tip in the cut of the nut on this string. The graphite lubes it and it might help with the noise. it certainly wont hurt anything.
7. If you have a low nut slot, take an extra guitar string you have lying around. Put an almost microscopic amount of superglue on it and dab a tiny-tiny amount into the nut. It's better to use not enough than too much. All it takes is like not even one fourth of a drop. If you put too much in it it's still not a big deal, because you can use your guitar string as a file.
You can also look how to fix the nut slots with mixing baking soda with superglue to make paste.
Be extremely careful to get the superglue just in the nut slot. This is important because if you ever need to have the nut taken out and you get some superglue into the woods of the fingerboard it could be a big mess trying to extract the nut.
8. Check the truss rod and action height. Probably they need to be adjusted.
9. If you're sure this is not a fret buzz, you need to start looking at other things. I've seen loose parts vibrate, causing buzz that is not easy to find … tuners, bridge parts, pickup switches, output jack, pickups, and in one case a truss rod that had no tension would vibrate inside the neck. Just a slight tightening fixed that, it had a little tension and couldn't vibrate anymore. Anything that is held in with screws is suspect. Does the nut itself move? Any loose parts can create a buzz. Start checking anything and everything. If the strings are not buzzing against the frets, something is probably loose. It could be anything.
10. If the buzz is caused by your aggressive play and you don't want to change the way you play, get heavier strings. If you play on 10s, 10-52 is the obvious choice - and make sure the guitar is set up appropriately for that. The heavier strings are tighter and you'll have a better time playing heavily.