Strongly suggest you use the YPAO for initial setup of your subs. I had to set the volume knob on back of mine to ~10-11:00 for setup. 12:00 made the sub so loud that the AVR room correction couldn't cut it back enough.
After, and only after you have the sub volumes correctly set up, then you can play with them. Your AVR has an on-screen setting that lets you increase/decrease the volume of your subs. You don't have to touch the controls on back of the sub.
KEW is right. For big Bing/Bang/Boom movies, I like to turn up the sub volume 5-6dB. For music, I leave them at 0, and often don't even use them.
One suggestion... be sure to set the sub Limiter Switch ON. (It's on back of the sub.) Read the instructions carefully, and even call Rythmik to confirm your settings and baffles. These subs could almost literally blow your house down. Be very sure you have them set up correctly to avoid damage to them.
You are going to pee your pants when you hear these monsters work.