quiet speakers and low bass

ok, i hooked up my system, its crappy products, but it doesnt play loud at all, can barely hear it over my exhaust

pyramid amp -pb1644- says 4000 watts
pyramid head unit
power acoustic woofer- 2000 watt, 700 rms
boss speakers...-500 watts each

idk if its the wire gauge im using? 18 gauge, but the gauge on the speakers is like.. 22? aha the wires are thin, and the head unit as well the wires are thing, then to the subwoofer i just used 18 gauge wire.. power and ground is 4 gauge, but basically im not getting any sound, and the woofer isnt pumping hard ( not enclosed case, just connected it to test it) any ideas?

volume is at full, just hacked teh wiring to see if it would all work..

it plays louder thru the ipod (aux) rather than sd memory card

i would definitely be using lower gauge wire. when i hooked my sub amp i was only running 400 watts, but i had 4 gauge for the power and ground, and then 12 gauge from the amp to the sub.