I was doing some testing and this feature is not possible.
Windows only sees the device as 7.1 when i do a windows test. This is after I turn off 7.1 on the DAC. My issue with this is I was able to do this properly with the Razer Tiamat 7.1.
So what I am saying is when I turn off 7.1 any game I load still sees the headset as 7.1 and operates in that mode just cutting off all sound from the rest of the speakers. Instead, it should convert to 2.0 speakers with virtual surround (optional).
On a side not Asus ROG... Thee Tiamat does a better job of using their discrete speakers for full 360 directional audio. The Centurion has a gap or blind spot of no sounds between the rear and side speakers. I really do like the sound punch from this headset. but lacks that in the rear speakers a little. Th