I have just started to mod up my S with some nice speakers (Sony 1621) and just ordered a Subwoofer (12" MTX). My question is that, if you get just one subwoofer do you need an amp? And just another question, What does the amp do? Just make it louder? Thanks alot

 

Since you don't know about amps... You do know you need a box for the sub right (unless you bought a pre-boxed one)?

As for the amp. YES you need it. You cannot drive the amp off the stock head unit ( at least I doubt you would hear or feel it).

What is an amp? Well I'm not the best one on the board to answer that, but essentially it takes a small lower power audio signal and "amplifies" is hence the name "Amp". How does it do it? Well I'm not sure and don't want to get flamed out by all the other techies by guessing.

What do subs (or any speaker for that matter) do? They move air (pressure waves are what you hear). A sub moves TONS of air. To move all that air requires lots of "power" and that is why you need an amp (to get more "power"). In essence, they make it louder as you suggested... but to even be loud enough to hear it you will need at the very least a small amp.. maybe a 100 wrms...

-- Robert

 

All subs need amps unless they are an all-in-one unit (which are usually mediocre). Download crutchfield's guide at their site. Its a good place to start. Read up on automotive stereo systems; get familiar with everything. You don't want to damage your car or hurt yourself.