Buzzing on 1st and second fret could also be a problem with neck relief - I'd check that first.
Here's how I do it - and there was a great article in last month's Bass Player mag that said a lot of the same stuff but I like my version better
Stuff you need: - A tool to adjust the truss rod. This is usually a pretty fair-sized allen wrench.
- A capo. A g*itarist might have one - if not, they're fairly cheap at the local music store.
- A feeler gauge.
How to do it:- Tune to pitch.
- Put the capo on the first fret. With the bass in playing position (so gravity doesn't goober up your measuring), hold down the last fret and measure the distance between the top of the 8th fret and the string. For starters, .010 to .020 inches is good - you can adjust from there if you need to. Someone here said a business card is a great field expedient measure and I think that's a great idea.
- Tighten the truss rod to reduce the amount of bow or loosen to increase it. Don't adjust more than 1/4 turn at a time and never force it. If you break a truss rod you'll end up replacing the neck, the whole bass or paying many dollars to have the fingerboard removed and the truss rod fixed.
Wood doesn't change shape easily or quickly so it's probably a good idea to recheck the neck relief the next day and readjust if necessary.
Then - you can adjust string height. There was a great article in
this month's Bass Player on this. If the neck is within spec I like my strings about 3/32" above the 12th fret on the B (or E) string and about 1/16" above the 12th fret for the G (or C) string.
Play the bass normally. Most people I know don't pluck strings as hard when the bass is laying on a table in front of you - what sounds just fine on the bench might suck mightily when you get onstage.
After you're done monkeying around with string height you can check intonation. This is easy with a tuner or a trained ear. I like to tune to pitch before each adjustment but some folks will tell you that's not necessary. Check the 12th fret harmonic against a fretted note on the 12th fret. If the fretted note is sharp, move the string saddle away from the pickups - if it's flat, move it toward the pickups.
String brand and string gauge both affect neck tension and intonation so if you change strings you may get to do this all over
hope this helps,
allan