Fretless setup troubles

[Espresto]

Normally I'm fine with setting up my own bass, but I've got a problem on my fretless that I can't solve. I have awful buzz at 1st position and open notes on the E and A strings. No amount of tightening or loosening the truss rod seems to help much, and to get it to go away I have to raise the strings to the point where the mwah disappears and the bass becomes difficult to play. What can I do?

 

[MglMatador]

Normally I'm fine with setting up my own bass, but I've got a problem on my fretless that I can't solve. I have awful buzz at 1st position and open notes on the E and A strings. No amount of tightening or loosening the truss rod seems to help much, and to get it to go away I have to raise the strings to the point where the mwah disappears and the bass becomes difficult to play. What can I do?

Perhaps the nut slot is cut too low?

 

[Turnaround]

If there is buzz in first position, then the cause of the buzz is not the nut. On open notes, it could be the nut, but not in first position. The problem is more likely that hump has developed near the first position and will require a fingerboard levelling.

It's easy enough to check the nut - see if a thin business card can slip under the strings right up against the nut. It may be pinched a little, but you should be able to slide it up against the nut. If not, then the nut may be too low, but your problem is not likely to be the nut if first position buzzes too.

 

[Espresto]

The nut is fine. I really hope I don't need a fingerboard leveling. There is literally nobody in the entire city who does that kind of stuff, other than Sam Shen, but that's DB stuff. Maybe I'll drop by his shop and ask. I don't know....

 

[XylemBassGuitar]

Have you measured the relief before and after the truss rod adjustments? Was loosening the rod actually adding relief to the neck, or was very little happening?

Usually when you get buzz on the lower positions only, the neck needs more relief. If you can get .010" of relief or more (measured by holding frets 1 and 17, then checking for space under 7 or 8) it probably needs a leveling, or some other work. If you can't get .01" of relief, then the neck or truss rod may need some additional work to add relief to the neck.