The subwoofer sound of bass is becoming more and more popular everyday. With music being so deep into our human culture, the system components of music will be popular pretty much no matter what.
Gaining bass out of a car audio system is literally an art in itself. There are a couple of different things that can be done to really make a subwoofer sound system a lot louder.
1. The correct pressure differences between the speaker fronts and backs.
A lot of people install new speakers in a vehicle but don't have the correct pressure differences. When a speaker doesn't have the correct pressure differences, it pretty much kills the quality of sound going through it. Same goes for subwoofers except that the sound quality is magnified by a lot more. There is a reason subwoofers are called loudspeakers.
2. Amount of cubic space in the enclosures.
For subwoofers, the amount of cubic space the box has inside of it is pretty much everything. If your suffocating the subwoofer with not enough space for it to work with, it will kill the sound quality like no other. By looking up the specifications for each subwoofer, you can find what you need to work with.
3. Type of enclosure.
The different types of enclosures out there can really change the sound levels in an environment. Vented boxes are to of said "twice the loudness" as sealed boxes now, but I'm not totally sure I believe that. Bandpass boxes are also very loud in different situations. It just all depends on what your environment is.
As you have found out, there are tons of variables that can really change the sound levels in an environment. If your looking to achieve louder levels of bass, do your homework and put in some dedicated work and you will see it all pay off.