windows treating 4.1 surround setup as 2.1

[Benson9a]

Hi everyone,
I recently setup a new surround system for my win 8 PC using a creative sound blaster z, hooked up with optical to a Yamaha RX-V375, and 4 Pioneer SP-BS22LR's, and a massive cambridge soundworks sub. After plugging them all in correctly, I only get 2.1 sound. The sub, fronts and backs all play but not as a surround configuration. In the creative driver if I click the rear speakers the fronts and backs play. This also happens using optical in the realtek manager. In the windows sound manager it says they are 2 channel, but I don't know how to change it.

 

[americanaudiophile]

Since you are feeding the Yamaha digital audio it will indicate on the front panel what your PC is actually feeding it. Assuming that your receiver is configured correctly play a known 5.1 channel source and check the receiver. If it show 5.1 channels you must still select the correct sound mode on the receiver.
I would play a test DVD to check this. Otherwise pick a spot in the movie that you know uses the rears. You can also connect a dvd player to the receiver directly to see if settings there are OK.
By the way you really should get a center speaker.