I work at a student run radio station, and our concert setup right now is pretty much a pair of Carvin 700W speakers, these things put out crazy, but I am looking for some nice subwoofers to add more punch to everything. I am not sure what my budget is this year for equipment, but would just like some info into what I should be looking for. I will probably have to buy a power amp for these things to if they are not powered.