I'm playing NGS with a 5.1 audio system hooked up via HDMI. It works great with PSO2, but in NGS the audio mix seems to be incorrect. In the middle of fights all of the action is coming out of the rear channels and only ambient noise is coming from the front left and right speakers.
I'm not sure if it's an issue with the mixing or if it's just a simple matter of the front and rear outputs being mixed up in the game. If I can rope someone in to do some testing while walking around my player character I can get a bit more data to narrow it down.