problem with 5.1

[Tom Bars]

I just set up my onkyo 606 and energy take classic 5.1 speakers. I couldnt be happier. For the size of my bedroom they work perfectly. But here's my question. I wanted to test out the 5.1 to some band of brothers and black hawk down, and to be honest the left, center, and right, speakers sound perfect,
but i didn't hear anything out of the rears. I even put my ear up to the speakers and couldnt really hear anything. So im asking
is there a setting on my Ps3 i have to turn on,
is it a setting on my onkyo i have to turn on,
or do i really have to pay my local bestbuy 100's of dollars to come out and "callibrate" my speakers.
any response or ideas would be greatly appreciated