Hi all,
I decided to do a quick measurement on the two towers vs attack of the clones. I only powered the sub-woofer. All other channels were set to small @60Hz. The results...

LOTR Dam breaking: 106db
Scene right after with bird flaps 105db

Attack of clones clone war 110db

So the quick answer is, ATOC has louder bass.
Both rattled the walls, with ATOC more at
the louder levels. ATOC had many more "events" that achieved this louder level as well.
So if your looking for thunderous bass, ATOC
wins. I still prefer LOTR as a movie, as I feel the story & acting is better.

I'm sure the measurement quality is weak. I doubt if the SPL meter was really meant to measure in thie frequency range. Mainly, I used the same position & range for the meter.