i'm getting excessive treble at the front speakers and splits. not enough bass. What i want to do is to trick the ears so that it feels like the bass is coming from the front but the rear is helping too

i'm looking at the amp and I see a knob for Bass Boost, Frequency, and Input. there's also a switch LP, HP, FLAT. both front and rear are currently set to HP.

what's the ideal setting? do i turn the knobs using a philips head screwdriver? the rear speakers are JL Audio 6x9 and the front speakers/splits are Kevlar Response.

thanks!