The Power of Room Acoustics
After much fiddling with speaker placement I finally found a way for my DIY speakers to play with nearly flat frequency response down to 35hz. I had no idea how much a role that room size and shape, and speaker placement played in affecting the performance until reading some of the tidbits on the Decaware website.
Previously I had an enormus black hole from 65-75hz and peaky perfomance all over the 40-110hz range including a resonation at 50hz that was mind boggling. It was really ruining my ability to enjoy music. After redesigning the speakers to play flat to 55hz (according to winisd modeling) and still encountering the same problems I looked further into room acoustics and speaker placement. Bingo! Talk about something for nothing.
I ended up moving both speakers to a different wall in the living room, facing toward the open french doors that enter the room. Now when I listen to acoustic jazz bass scales all the notes are in sync with each other. No more +10db, -7db irregularities that were driving me nuts. Additionally I gained on the bottom end from 35-45hz where it had previously rolled off. I wouldn't have thought the extra 10hz would make that big a difference but it actually tamed the mids and highs a little, as well as giving the extra thrill of really deep strings.