The action on my bass (Ibanez SR600) is not even. the action at the last few fret is about 5 milimeters, and the action at the first fret is just about zero. what astounded me is that the bass only buzzes on certain physical positions. when i'm sitting firm with my back strait and the bass on my hip, it doesn't really buzz, and when i sit more relaxed and reclined, with the bass resting againt my stomach, it barley makes any sound except buzz. the buzzing only occurs on the first 5 or so frets. also, the D string (which has been on a shorter amount of time than the others) buzzes more, and on "steeper" positions. is this action normal, or is my neck unstrait? does the action have to be dead even? how do i get the action even, and keep it as low as it is now?