Originally Posted by
NoTLaDStyle
It is not possible to connect the subwoofers and the front speakers to the same outputs. You will need another small amplifier to drive them. Unfortunately most cheap amps will produce lower quality sound than the stock headunit - which is rated at a very low RMS wattage but has more stringent response and a highs signal to noise ratio (clarity and cleanness)
The subs are meant to produce only bass notes and should have a 'crossover' which filters out all the higher notes that arent bass.
The front speakers are meant to produce everything EXCEPT very low bass which makes them and the subwoofers mutually exclusive.
Not impossible. Most 2/1 channel amps will run in a 3 channel mode. IE, a mono sub, and stereo mids/highs. The secret is properly designed passive crossovers...caps and coils after the amp. I've seen many, many very high quality systems done this way.
Now, is it practical, probabaly not. In some competition settings, it is desirable, like to stay in a very low power class, for example. Otherwise, there are some high level audiophile benefits, but not much for the casual user. By the time you pay to have the passive crossovers designed and built, you could most likely by another amp.
Dalton is correct that most 'cheap' amps suck, and you'd be better off on head unit power. But, if you have some money to spend ($100 up) you can get some pretty decent stuff. Or, you could go used, but that's another crap shoot in and of itself.
Toby