I'm using an nVidia GeForce GTX 660 on a Windows 8 Pro machine. I have 2 monitors, exactly the same model, both capable of playing sound through HDMI. They're both currently connected using HDMI (2 separate ports on the graphics card, using "DualView" not cloned).
At the moment I can only set 1 monitor as the default playback device. I doubt this is possible just with Windows but is there some way I can play sound through both HDMI devices at the same time?