I just got the game yesterday and i was playing the game at a friends house. We experienced the no sound thing after 20 minutes of play and we just thought it was some wiring in his system, so we carried on. I started playing it at home the next day and had the same thing happen, if you really want to play the game now and not wait for the patch you wait until you reach checkpoint then exit to your Xbox main menu, eject the game then put it right back in. When on the games main menu if there is no sound go into the in game menu and wait around 1 minute, if it takes longer i don't know what is up. But if your sound turns back on then just exit the menu and play as you should, with sound. I'm just doing this now so i'm not sure how long it will last until it goes out again, but still this is not, i repeat is not a permanent fix, its just a way to play the game for now. Hope this helps, it worked for me.