I might have to get a new subwoofer soon. I love the one I have now because it's almost the only subwoofer I've ever been exposed to that doesn't give lower frequencies that bullshit Hollywood bass boost that rumbles the house, and instead just gives me what I would hear if the movie/music/etc. was actually happening in the room. I'm wondering, how can I shop for that kind of subwoofer when most of them don't do that? Preferrably something simple--not an entire speaker set. I go modular with my speakers so that they're easy to replace, so I'd love something that doesn't have some separate iHome-style box and maybe even no options of its own. Just a box that plugs into TRS and gives me the lower frequencies I'd be hearing in real life.
That sort of depends on what genre of movies you watch the most. If you watch movies where things blow up, then I don't have an idea how you get that to sound like it's happening in your room without including some ridiculous idea of what an explosion occurring within your room - one that you might survive but would otherwise bring down half a large city - actually sounds like. If you watch dialog based films, then that sort of bass isn't put in the soundtrack. So ...
Give us more information. What's your budget?
What sort of films are you watching that you might use a demo?
What is your current speaker/sub set up? Your AVR?
How much flexibility do you have in placement of the sub within your room?