The best way to improve bass performance is a corner trap, or two, or three. The improvement will be in both reduce mode/nulls as well as tighten up the overall bass performance in the time domain (dynamics).
You can also purchase or build tuned bass traps for specific frequencies to addres those modes, but it can be costly and.or time consuming.
Thank you for the warm welcome! One of the first forums I visisted recently was soundvision. Boy has that dried up. Anyway, after looking around a bit I noticed most of the regulars I enjoyed talking with headed over here...so...
I've been spending a lot of time on various hobbies. Old muscle cars, ATVs,enjoying film and theater,and of course...audio speaker and subwoofer design. Things are starting to get very busy around here but I've never been much for hyperbole and such so I'd rather not get into specifics just yet.