Marantz AV7703 - Odd crossover setting necessary


I just got my Marantz AV7703 hooked up. The first thing I noticed was that it sounded like there was a big gap in frequencies around 150Hz +/- 50Hz. (approximately) It sounded like there was an EQ setting somewhere with that frequency range turned way down. I tried running the Audyssey audio setup, but that didn't help much. It turned on some "reference" EQ mode that dropped my high end and it sounded awful.

I have my main front/left speakers set to "small" and crossed over at a 80Hz high pass, and the subwoofers are set for 80Hz low pass. But it sounds like there is a lot missing. Oddly, when I change the crossover frequency on the front left/right speakers from 80Hz to 250Hz, all the missing bass comes booming back! Why would this be? Going up to 250 should just remove even more bass!?

Marantz AV7703 preamp
Kenwood VR-6070 receiver (bypassing as much as possible, only using as amplifier)
Custom made Front Left/Right speakers.
2 SVS SB-3000 subwoofers.
vman97

I’ve usually found Audyssey very good.
I know you shouldn’t, but try try setting the mains to large (no subwoofer), run Audyssey again. (Usually picking large mains auto turns off the sub anyway)
After that turn on subwoofer and manually pick where you think the sub should come in and adjust the level. If you have big floor standers 30hz small ones 50hz bookshelves 80hz.

Cheers George
Even running just the mains only and set to "large" still seems like a lot is missing. I wonder if my  Kenwood receiver I'm using as an amp is the source of the problem. I am bypassing as much as I can. But who knows what is going on in all that circuitry. My next purchase is a real amplifier. Once I get that in place, I'll reassess this. 

Thanks!