I have a Yamaha RXV-657 for my receiver and Aperions 10" sub. When I run the YPAO set up on my receiver it always (no matter what placement of sub or Mic) sets my crossover at 200. The directions for the receiver say to set the crossover to max and the phase to zero before running the set up. It sounds good to my somewhat untrained ears but am I getting as much as I could out of my system? When I go in and set it to 80 it doesnt sound much different at all but the crossover set at 200 goes against everything I have red about set up. I havent used any tests discs yet although Digital Video Essentials should be here tomorrow from Netflix. I also ordered Avia but its on a wait list.  I am really not sure how to use the SPL to calibrate the sub with the rest of the speakers. Any thoughts on this would be helpful. Thanks!

I don't think with any subwoofer you'd want to set it above 80hz, I've read the main reason for this is because above 80hz is when bass starts to localize (when you can tell where it's coming from), which you don't want to happen. So say your front right channel produces a localizable bass , and a subwoofer on the left plays the same bass, it might cause the bass to sound like it's coming from between the two instead of on the right where the speaker is, kind of like a phantom channel. It's hard to explain and I'm just interpreting something I've read elsewhere. If you have the 533 bookshelfs, they go down to 80hz, so that's about perfect for crossing over to a sub.