Neck Relief

[lowend1]

I've found that if relief and bridge adjustments don't do the trick, many times the culprit is the nut. A properly filed nut can make all the difference in the world.

[patman]

I have noticed with some banjos I have set up over the years, that you need a decent amount of relief for the instrument to play properly in tune with itself. Almost as if some relief was assumed in spacing the frets (we're talking turn of the century -the last one-banjos) One probably doesn't notice it as much with a bass because of the lower notes and darker tone color-you're not going to be able to detect micro intonation problems as much.

[dadagoboi]

I've found that if relief and bridge adjustments don't do the trick, many times the culprit is the nut. A properly filed nut can make all the difference in the world.

Absolutely.  The most neglected part of a DIY setup and the most critical for intonation on the first 3 frets, even more than setting 12th fret intonation.

Most instruments come from the factory with slots cut too shallow, it's safer that way.  The result is frets 1-3 are sharp even though bass is in tune open and at the 12th fret.  This is because of the extra distance required to push string down to those frets relative to the others.  String height at the first fret should be just above it.

[lowend1]

If I'm feeling adventurous, sometimes I will deepen the slots - an educational process for sure, but you really need to do it frequently to "become one" with the job at hand. The first time I had a professional nut replacement done, it made me want to take every one of my basses in. A huge difference.

[patman]

I usually try to get those nut slots as low as they wil go...if I go too far, I will drop some super glue in the slot and reshape. Probably not the right way to do it, but it works for me.