BillFitzmaurice.info

Again, what is the story if you move the sub? It's not quite adding up in my mind.

The locatable bass has to be coming out of the sub or else induced vibration in the building itself. I think you'll have to invest in a reputable crossover, cheap enough.

If I move the sub to the front left corner of the room, it sounds beautiful. Bass is less locatable (at least it's coming from the front where the action is) unlike when it was in the rear corner, and, the bass is even stronger than when it was in the rear, another plus. Unfortunately, this doesn't tell me if I'm getting unwanted frequencies out of the subwoofer.

I have thought of throwing in a DSP or something down the road since they're pretty cheap, I can even borrow the one from downstairs someday and see what that can do for me.

Disconnect the mains, and listen to only the sub. During scenes with only spoken word, you should hear nothing.

Just tried that, nothing noticeable.