If you set the fronts to "large" then the DefTech BP7002's will get a full-range signal. Likewise for any other channel set to "large." The subwoofer output will still get the LFE channel of 5.1 soundtracks as well as low frequency data from any small speakers (assuming you have any), which can then be fed to a separate subwoofer.

When speakers are set to large, the crossover adjustment is still available, but it is actually being ignored - even though the setup menu doesn't remove the control.