DSP = digital signal processor. It's a generic term. Mine provides cross-over selection for high pass to one set of pre-outs, hp and lp for a 2nd set, and lp for subwoofer. I also have time alignement on 6 channels, 5 band parametric or 7 band graphic eq. Those are the most important features it offers for me. I have the option to attach alpine's imprint processor too. A few of the more popular dsp's in car audio are jbl's ms8, audison's bit one, behringer something rather(image dynamics use to adapt the power supply for dc since it's a ht piece), the h700 and h701 by alpine, and i don't want to list anymore.
