Do I need a sub?

[scottjoplin]

The bit about large rooms being needed for deep bass is entirely a myth, which I'm a little saddened to see perpetuated. Headphones work. QED.

I agree deep bass in small room is entirely possible. However, I think headphones produce good bass because of extreme proximity, very low bass can be heard if you put your ear very close to a speaker

 

[phase]

Either a sub or some much higher powered amp/speakers. Maybe some processing goodies as well, time alignment for different frequencies.
Dance music can be like a carnival ride with some well delivered bass.
Car speakers are meant for use inside a box; where you are inside the box(the car).
Probably some good options out there, just takes funds unless you can wheel and deal, trade up...