Even with clean, buzz-free playing technique, an ukulele with one or more mechanical problems could continue buzzing inherently.
In this lesson, I’m going to lay out some of the reasons an ukulele might buzz mechanically.
What is a Mechanical Buzz and How Does it Happen?
An ukulele is built to resonate. This creates a beautiful sound, but it is also the reason mechanical buzzes happen.
You pick a note, causing the uke to vibrate, and some component bounces on and off of another component repeatedly. This creates a buzzing sound.
Because ukes resonate so nicely, it can be tricky to find where a buzz or rattle is coming from. A problem at the bridge can sound like it’s coming from the headstock – and vice versa.
Check the Metal Components for Rattles
The frame of an ukulele rarely rattles. It’s all the extra stuff that is added to it like machine tuners, pickups, and strings that usually cause problems.
Nuts, gears, and wires – anything that could possibly rattle against something else can be a culprit.
Pickup
In my experience, the most common reason for buzzing is a loose pickup component.
The pickup endpin washers and nuts have the tendency to loosen over time if not installed well. This is usually pretty easy to diagnose since the jack will be loose, but harder to fix because you often need to tighten the nut on the inside of the body.
Loose electronics wires are also a problem when they come into contact with the inside of the body. This is why it’s important to bundle as much of the extra length into a zip-tied wrap as possible – so there are less places a wire could touch. Where wires do need to be secured, use clips like this to hold them in place.
Tuners
Tuners can buzz when a string is plucked. If the mounting screws or center assembly screws are loose, you’re often rewarded with a rattle.
I’ve had bad luck with my Gotoh slot headstock style tuners buzzing intermittently, depending on which position they are in. It took me a very long time to figure out what this buzz was coming from. If I need to record, I’ll often put a hair tie or rubber band around the tuning buttons to hold them tight.
Braces
Sometimes the internal bracing of an ukulele splits or comes unglued. This is the worst possible source of a buzz, but is fairly easy to isolate.
Stick your finger or some sort of dampening tool inside the body to touch the problem brace. If the buzz goes away when you hold pressure on the brace, you should probably take your uke to a good repair luthier who can tighten things up.
String-Related Buzzes
Since strings are the part of the ukulele that moves the most, they’re a very likely culprit when you’re looking for a rattle or buzz.
Loose Tie Ends
If you leave the tied ends of your strings long, regardless of bridge style, they can buzz against the body of the uke.
It’s a good policy to trim them short once the strings are settled in to avoid this problem.
These string ends aren’t long enough to touch the top and buzz
High Frets
String buzzing on an ukulele is usually caused by a high fret. If one of the fret wires pushes up from the fretboard (which can happen over time) or was never properly leveled from the factory, it will inhibit the string from ringing cleanly.
When you play lower than it, the high fret gets into the vibrating path of the string. This is why specific frets tend to buzz, but not others.
To check for a high fret, you can lay a precise straightedge across the frets and see if it rocks side to side. I really like this little ruler from Stew Mac, but it’s a little long for this purpose so a lot of people use their purpose-built tool for finding high frets.
Alternatively, if you don’t have a straightedge, you can play the fret above the one that is buzzing. If it doesn’t buzz, odds are the fret creating the second note is the culprit.
In the past, I’ve been able to gently push down on a raised fret myself to fix a buzzing problem. But usually it won’t be possible and you’ll have to take your ukulele to a pro who can level the frets.
Low Action
Depending on how straight the neck is and how level the frets are, the strings can only be lowered so much before they start to chatter on the fretboard. This is rarely a problem since factory ukes are most often sent out with high action. However, if you request a super-duper low action setup or sand the saddle down too far yourself, your strings will tend to buzz more than on other ukuleles.
If you play with a soft touch, you can often get away with a low action. But if you strum and pick with a super strong attack, the same uke will buzz like crazy.
To correct low action, you need to raise the saddle. This can be tested fairly easily by removing the strings, removing the saddle, and adding a thin paper or wooden shim under it.
The permanent fix would be to create a whole new saddle. This can be finicky, but isn’t rocket science. If you’re a bit crafty you can buy a saddle blank and some sandpaper to make a new one. Just don’t throw away the old one in case you can’t get the new one to work.
Other Causes
If nothing on this page seems to be the problem, check out the big list of possible buzzes over on Ukulele Underground forum.
When trying to locate a buzz, be methodical and thorough. Don’t guess. Don’t assume. If you think it’s one thing, run a little experiment to try and isolate the problem.
If in doubt, take your ukulele to a luthier.