I've read that you normally can't tell where exactly the sound from a subwoofer comes from. Yet there are "directional" subwoofers, meaning that you should set it up facing where the audience will be. That confuses me a bit. I'm interested in a subwoofer that diffuses its sound in such a way that it kind of envelops you, making it very hard to pinpoint where the sub is actually located (in my case it will sit in a corner about 8 feet from the couch). I'd appreciate any comments on this. Also, any recommendations (below $150. if possible)? Thank you.