i have everything hooked up to where you can here my sub and my deck goes on...the only thing wrong is that when i here the words on the song it has to be maxed out and i can barly hear it....but the sub works fine....i need help thanks

 

usefully this is caused when the wires for the speakers are crossed that is on has the connection inverted. since the sub is working fine i'd say that what i've just said is very likely. but to make sure you should look the speaker connections over. also what year s13 do you have? you may be dealing with a factory amp and need to bypass it.

 

i have a 90 single cam non se