A single Aerial sw 12 sub could be all you need . Two is better of course as each could be used for seperating bass for each channel but the unit has a switch for summing the input. It also has a switch for movie and music and you can optimize the sub for both. Other than that , the SW 12 is a fantastic sub and would mate nicely with your speakers. Beautiful , near indestructible and harmonically rich ; music reproduction for this unit has few peers. For theatre , it is very good to excellent.