As far as I can tell, there isn't a yes/no setting. But on the speaker setup screen, I have the sub slot set to "L/R+LFE". When I set all the speakers to "small" I believe that setting automatically changed to "LFE". In setup*there should be a "YES" input for SUBWFR. For LFE, select SUBWFR only if you leave speakers to SMALL.