Before anyone suggests, yes i have considered the KEF 2500 the BK XLS 2000 and the Ruarks. However I'm interested in the MS 309 and MS409, however what are the key differences in PERFORMANCE? The MS309 on paper goes down to 35hz but the MS409 goes down to 38hz on paper. I know figures should be thrown out of the window, but since they're coming from the same manufacturer, does the ms309 dig deeper than the ms409? The MS309 works very well but is the MS409 any better? I'm looking for a musical sub so can anyone anwser my question to which one is better?