re: Post your subwoofer

Very likely Audessey is the problem.

It's been almost 2 yrs since I was a daily reader over on the audioholics.com forums, but there were threads about this issue and they were discussed ad nauseam.

Can't recall if the problem ever got solved either

Maybe some changes were made to Audessey, but probably not, if you have the same issue.

I tried to run Audesssey with the gain turned way down on the sub, so that Audessey would boost a weak signal (plus I could further turn up the gain knob if necessary), but this didn't work. Couldn't fool the system, so I gave up. Now might be a good time to revisit the problem, look/ask around for solutions.
Please post whatever you can find.