Yeah, better not to damage them if they were going to be returned. So, I tried different settings in the RX-V6A. Regardless of speaker size or the Extra Bass feature being ON or OFF, the subwoofers were active when set to Use. Many posts ago, I remember my TSR-700 had set my speakers to Large after running YPAO and the subwoofers were active. Your unit should function this way as well. If not, something may be going on with it.