You probably could run your subwoofer off of the rear speaker outputs of your head unit, but you probably would not like the result.

It takes a great deal of energy to make bass tones and the power output of your radio is relatively limited.

The 'subwoofer volume' option is so that you can set the line-level output to a separate subwoofer amplifier and keep the subwoofer level proportionate to the main sound output.

Good luck.

no you need an amp to push all the power that you would need to your sub. best thing to do is find the rms watts of your sub and match the rms watts of an amp and in the right box it will slam. keep the rms of both subs and amp around the same. too much power will blow the subs and not enough will damage the voice coils. so you should not exceed more than 100 watts rms over or under the rms of the subs.

Sorry but the sub volume control on your head unit just sends a signal through your remote wire that will TURN YOUR AMP UP IN THE BACK OF YOUR CAR. So the sub button in more like a volume button for your amp. So, I don't believe that you can hook your sub up without an amp.

ive got the new sony head unit in my ST, and want to connect the aux leads from my amp to the head unit,iv got an adaption lead from the aux- the head unit but dont know which 2 wires to connect so i get sound!????

Any help or ideas would be greatly appreciated!.

THANX!...