Some people leave their EQ settings flat (at zero all across the board) and others like to adjust them for a warmer or different sound. I have my bass set at 5 (out of 10), midrange at 2 and treble at 2. I keep my fader stage set at zero though between front and rear and left and right so it's even through out the car.

 

I keep mine set at "piss of everyone who doesn't like my music".

 

Treble and mids are flat, F + R, L + R are at zero, and my bass is set at 2 (out of 10).