Windows 7 - good subwoofer and bass speakers?

well I've been using some altec lansing surround sound speakers running on real tek hy tek operating software and it can handle alot of bass it's just sometimes I need to edit the pitch of songs on lower ghz songs. So on the songs I look at with the extreme bass boosts I've been seeing alot of quantum speakers and subwoofers I wanted to know if there are also some that are configured for a computer or maybe have an adapter so a laptop could be plugged into the set to play songs and also wanted to know good softwares that I could bass boost some of my mp3's that I own. thanks in advance.