What's your room like?  Size, finishes, setup?  Small/square/hard with loudspeakers/listening positions near walls are all bad.  
Suggest reading Floyd Toole's "Sound Reproduction" (either/both editions) to learn how loudspeakers/subwoofers behave in-room.  Toole is recognized as one of the world's leading acousticians.  Virtually every room has severe bass peaks/dips.  Multiple carefully placed subwoofers is the best way to address the issue.