I am having an odd buzz/muted sound at the fourth fret. Typically I would think the action is too low or the 5th fret is too high, but neither of these is the case. The frets are level and the action is fine. If I push down hard, (much harder than I should have to) the sound does improve some. I'm trying to figure out what the cause is so I can fix it. Any ideas?
Is the buzz on all strings, or just one?
It is predominantly on the 3rd string. The other strings have a small amount, but the third is pretty bad.
Double check that the frets are indeed level.
If they are, start checking for a sympathetic vibration. There are a lot of things that can vibrate on a banjo-- a loose hook, the tailpiece, an armrest, etc.
And it wouldn't hurt to change the strings, even if they are new. A bad string can make odd sounds.
Other possibilities are a loose fret or a loose glue joint.
You said 4th fret only with 3rd string. Is the fret near the 5th tuner? Is it possible the fret is not fully seated and need re-gluing in. Try the tap test across the full fret and the board and listen for a change in tap note. Do this on first 5 frets. I would check all slots at bridge and nut. Try a higher bridge to cancel out any frets touching strings. Double check head is not torn under the tension hoop. Maybe tap test bridge just in case that the top is separating
I would check that the truss rod nut is not loose. I have also has instruments where the fretted string would vibrate between the nut and the fret behind the note you are playing. So if you are fretting the 4th, check to see if there is a sympathetic vibration between the nut and the 3rd fret.
For one quick check.
Might try spiking the 5th to see if it goes away. Had a bone pip split one time and I guess it was vibrating against the 5th fret when hitting other strings.
Put an ear close to the banjo--bridge, nut, pip, frets, pegs, j-hooks--to see if you can detect the source.
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