Am I doing something wrong, I connected my iPhone via a QED lead to my Denon 1910 to play music and I was only getting sound from the front surrounds and centre speaker, is this what should happen ?
on the back of the denon remote open it up & you can change it by pressing the cinema mode, or any of the other configerations that are in the white highlited area.
As mentioned above, you can try running Pro-Logic II or dts Neo:6 processing or something similar, but the results with compressed music files may be unpredictable.