jay, I have an AVR that is similar to yours that will only go as low as 100hz on the crossover. It's a HiTB receiver from Pioneer. It's solid, but it's odd that  the cross over can't be adjusted much. the only options I have is 100, 150, 200. 200? yikes!

 So, with that in mind, since I am also looking at the 12D, I will be interested to see how you solve your issue.