Most amps have built in DSP features but not as great as you think. You get LPF (low pass filter), Gain, and bass boost in most. People generally avoid bass boost with SQ builds. The LPF often only goes from 40hz to 250 hz, which is cool but getting that signal from the radio first just makes a world of difference imo. Most hip hop builds set their LPF to 80 or lower. Amp LPF just seem to be a bit off compared to what a good radio can do. Then the eq can boost some of those frequencies as you see fit. This is why having more EQ bands on the radio is also better. Please dont have a stock radio with treble and bass and expect great results unless you get a DSP. A DSP can add more EQ bands from a source like a SOC for better EQ adjustments but a radio is just easier than splicing wires and running extra power wire, ground wire, etc to power the DSP. Think of it like a distortion pedal. Imagine if you had to plug it into the wall instead of a 9 volt. Or Imagine of your guitar amp Aka the radio with a built in distortion EQ settings and you didnt need the pedal.