First off I spent a few hours at a local music store and played a few Q5's and Genisis 5's. I must say they blew the door off of the rest off the basses in stock!! One I like the most was a Q5 loaded with EMG's, the barts didn't do it for me. The bass with the emgs had 4 knobs, 2 of which were stacked. The sales man was telling me the stacked knobs were treble bass and mid control, unfortunattly that leaves one control left???. So which preamp option was this and what are these stacked knobs controlling? Thanks.