determining factors for low action with no buzzing

[themajorrager]

so ive got 4 basses and three (yamaha BB615, Warwick Streamer LX, Vantage Performer '84) i have setup with very low actions but they dont have any buzzing. i try to setup my fourth bass (yamaha RBX 800) the same but cannot get the same result.
so what factors determine a basses ability to get a very low action without buzzing?
just for refernence the bridge on rbx800 is just about the most adjustable bridge you can get so it aint the bridge holding it back...

 

[Steve]

Truss rod and fret leveling

 

[AlembicPlayer]

level frets, truss rod, nut slots and bridge saddle adjustments.

it's not rocket science, but it can be tricky business if you've never done it.

 

[themajorrager]

level frets, truss rod, nut slots and bridge saddle adjustments.

it's not rocket science, but it can be tricky business if you've never done it.

umm no disrespect but it doesnt seem you read all my post - i have done this MANY times before and have acheived great results in the past with my other basses ALL having very low actions and no buzzing

my question is why cant i do the same with the RBX 800?