Of all the responses so far, yours seems to be the most plausible, i.e., the one that makes the most sense to me. Some of the bass I was hearing was obviously "dirty bass" and now that everything's all cleaned up in the upper octaves, I guess I'll have to move my speakers a little closer to the rear wall. Not a problem, I've got 3 feet to work with so hopefully everything will fall into place.
Cable Elevators killed my bass
I purchased a set of 8 Cable Elevators locally on consignment recently for experimentations' sake and was shocked to hear how they seemingly sapped my speakers/system of a couple of hertz of bass output. I have stand-mounted monitors with limited bass so this effect was not subtle. However, every last vestige of grain, haze and artifice in the mid and upper frequencies was gone (and I mean GONE!) as well so this tweak seems to be a double-edged sword that I feel like falling on. Anyone else out there have a similar experience with disappearing bass?