I am looking for a decent powered subwoofer that I can use with these speakers.http://www.edifier.com/us/en/speakers/r2000db-bookshelf-bluetooth-optical-rca I will take any recommendations, but know that the top of my budget is at the absolute most $250. So please tell me watch you think about what you recommend. I would prefer that you have first hand experience, but if not that is also ok.