I recently moved from stereo to a 4 channel config, but when I play any video like the one in the image I only ear the front speakers. I'm using zoom player and have tested with Core player and BsPlayer (although it doesn't support mp4 I think), with the Convined Comunity Codec Pack which is probably the problem....

I don't think the speakers/sound card are the problem since they work well in games but just in case I have a Sound Blaster X-Fi, obviously on a 4 speaker config.

I hope someone could help me plz...