Question Sound for rear surrounds plays through front speakers - SPDIF out from Audigy to 5.1 receiver

[mossi]

I connected my HTPC via optical out SPDIF through my Soundblaster Audigy to the 5.1 receiver Yamaha RX-V377 but the sound for the rear speakers comes out via the front speakers..

I'm using potplayer to test this and I've setup the passthrough or so I think I've done it correctly but when I play a test AAC 5.1 file the fronts and center work fine but the rear surrounds play through the front speakers again..

I get the same when I try to configure the speakers via Windows 10.

When I check SPDIF out options in the Sounds menu it only shows me 2 channels.. is that right?