Here is how things worked out:
My neighbor to the side was playing his music loud (or rather his teenage son was.) The person above him came down and chastised him about it. This got me concerned about mine again, so I turned the sub down even more. At some point, I realized that it was no longer even coming on, and that I wasn't hearing any difference. Apparently, whatever "benefits" it had were illusory, and my Boston VR2s have sufficient bass on their own. It is now sitting in a closet, where it will remain until I decide what to do with it. (Perhaps I will keep it and try it again someday if I ever buy a house.) I have been in my apartment for years with no complaints, and I want to keep it that way.