Reciever question

[Ace Pace]

I recently received a Denon AVR 2307 receiver and I'm having some problems connecting it properly.

Input is HDMI from an nVidia ION box, which is configured to output 5.1 (can also change to stereo). Output is HDMI to a big screen and 4 speakers (two front/two back).

However, no matter what set of settings I set, the only sound I receive is from the two front speakers, even when the receiver is set to 5.1 sound, or any of the multiple stereo to 5.1 outputs (or when setting the sub/center to non existent).

This is the first time I'm configuring anything sound related that is more complex than two speakers and some advice or where to look would be helpful.

Needless to say that the Denon manual is no help, but this seems to be a common theme. Also, some feedback on the receiver itself?

[phongn]

Are you actually outputting 5.1 audio? Check your codecs; it might be mixing to two-channel.