Folks,
Sorry for the slow response, a glitch has prevented me from posting the past couple of days. At any rate, thanks for all the responses, it's nice to know that a lot of you can relate. I have indeed thought about introducing a subwoofer into the system, although I honestly wonder whether it wouldn't aggravate the problem in some ways, and would really prefer to keep this a two-way setup. I guess the crux of my problem is that I am generally pretty obsessed with maintaining a clean signal path in the system and hate the idea of introducing a substandard piece of equipment into the chain.
That said, seems like the Behringer is worth a look. Do I gather, though, that this involves digitizing an analog signal then converting it back to analog? Scary. To answer your question, Elizabeth, I do have a DAC that I really like a lot. Anyway, i obviously need to read up on the Behringer. Will also check out the ADC, thanks for the rec on that, Albert.
As for isolating the speakers from the floor, I've currently got them on some Herbie's spikes which are in turn going into the Herbie's gliders. My feeling is that they do a pretty good job. My concern, really, is not so much about the bass traveling through the floor from the speakers themselves, but more just pressurizing the whole apartment, along with the neighbor's - this is a 100-year-old townhouse and we can hear each other talking on the phone, etc. A nightmare, basically, which has indeed conjured many a thought of moving to a bunker. Too bad because we love everything else about the place.
It's funny Elizabeth - I too have grown up, for better or worse, and honestly do sympathize with my neighbor. Per your point about syncopated beats, I do think that has something to do with the fact that I've been listening to a lot more jazz since I moved to this apartment, and somehow feel guilty putting on rock and dance music... sigh.