I have been trying to figure this out for 2 days now and I cant think of anything else to do. I have a Sony STR-DG820 reciever and my Xbox 360 is hooked up via HDMI cable for A/V. For some reason when I play an Xbox 360 arcade game it will not be in 5.1 audio, instead it goes to 2.1 stereo. This only happens for the arcade games though. If I am on the main dashboard or I play a regualr 360 game like Gears of War or something it will put out 5.1 audio. I dont know wheter it has anything to do with the new Xbox update or not but I cant find anything wrong with the settings on my reciever. My PS3 is also hooked up via HDMI and works prefectly and I compared the settings on the reciever and they are the same for both systems. It dosnt make sense to me.

Do the Arcade games have 5.1 sound?

This would be a really dumb question if they werent. All the Xbox Live arcade games are redone in HD and 5.1 sound. Before this update I had no issues but if anyone is familiar with my reciever and has an idea as to why the reciever would be the problem please let me know. I have no issues with anything else that uses HDMI in my setup.

No one has any ideas.

I also tried the optical cable today and it does the same thing. If you guys cant help me then I dont know where else to turn. :confused:

I think you are confused a bit here. Xbox Live Arcade games maybe in HD and advertised as Dobly Digital, but almost 90% of the Arcade games come in Dolby 2.1 or 3.1. Its very rare you will see them in 5.1

If you are getting full 5.1 or 5.0 in your actual games, but the arcade ones don't, and if you don't touch any settings, then obviously they are only in the lower feilds.

Hopefully the OP got his answer since the last post on 12-18-08. :)