I have a 5 string bass.  I pretty much set the action at the 12th similar to my treble guitars.  The intonation is pretty spot on also, the problem I have though is when I play it with any kind of thumb thump I think it is hitting the frets\fingerboard. Playing with a pick helps, but not the tone I want.  Should I raise the action, or set action at a different location?  And will raising the action effect intonation drastically?(more string being displaced to fret a note, essentially bending the string, etc.) Thanks.