Looking to purchase the Mission m30i or Wharfedale Diamond 9.1 speakers to upgrade the sound of my LCD. I did want it to be a 2.1 system like the Onkyo HTX 22-HD with an active Subwoofer that powered the other two speakers too..will this method work? Which subs are capable of doing this or will it be better just to power the two speakers and leave the sub out if so how do i go about powering the two speakers? Thanks.