sound quality and volumn have little to do with each other.I to live in an apartment and must restrict my volumn levels,but i have good quality speakers and good quality sound.Doing what you are doing now wont change the fact that if you want to take your sound to another level you need new speakers.Not sating that they are bad,but they are limited in what they can do,they dont have enough range.They only go down to 120hz,if you have your crossover set to 80hz that is to big a gap.

bill