I've been trying to figure this out for a while now and I can't figure it out. I am trying to passthrough audio (via optical) from my PC (Realtek 889) to my Marantz sr7000. The sound works fine, but how come I can adjust the volume and set DSPs on the PC? I thought that a digital out to a receiver would bypass any processing from the PC sound? I've concluded that it is Realtek driver, but does anyone have an insight to this matter? Thanks.