surround (5.1) export not working

so here’s my problem: I do a 5.1 channel project routing each channel to 5.1 mix. I export to 5.1 wave (48/24). But when i go to play this file back on my Denon avr-s700w receiver i only hear 1 or 2 of the channels. I see all the channels in output channel of Cubase but even if i put the wave file on a thumb drive and play it on the Denon directly from the drive…channels missing or real low. The Denon plays 5.1 auto matically from commercial dvd playing in whatever format the dvd is…(dts or dolby). But when i play the cubase export the Denon does not register that it is a 5.1 channel wave file…stays stereo. or multi channel. Any help would be appreciated . thanx