UPDATE, based on Fishorama's suggestion here:Personally, I would move the AC intake toward the tank center & maybe add an extension or 2 to the intake. You could also duct tape off those weak center bubble wand places, you can clearly see where I mean.
I just took off the prefilter and moved the entire AC110 towards the left, up until I couldn't go any further against the center brace (so now both the Aqueon and AquaClear are as far LEFT as possible to avoid bubble intake). As a result, it seems like significantly less bubbles are going through the filter, and the noise isn't nearly as bad as it was before.
I've since put the prefilter in the cabinet to use somewhere in the future, if necessary.
The thing about the shorter intake on the 110 is this: I have the Aqueon filter on the left extended pretty far down into the tank so lower-level debris can be sucked up by it, and that's why I kept the AC's intake shorter, my reasoning being that perhaps that HOB would take care of the upper/mid-column water debris...