what part do amps and crossovers play in car audio systems?

Friday, September 24th, 2010 at 3:54 am

i just bought a pioneer stereo and i have sony xplod 6" speakers in each door, 2 tweeter in the backseat, and 2 subs (not sure about the brand, but i think they are new). can i hook up the system just as it is?

what exactly is an amp and a crossover, and what do they do? are they necessary components in the sound system or can i go without them?