hi i recently bought a hi-fi with a digital optical connection with the intent of connecting my xbox 360 to so i can have surround sound instead of connecting using the red and white cables. when i connected the optical cable there was no sound at all. the signal was getting through the cable ok as the red light was coming through. will this have anything to do with the optical on my hi-fi being audio out? if so, whats the point in having an optical out on a hi-fi??? or will optical definitely work but i must have a faulty cable? im quite disappointed as most of the reason why i chose it was because of the optical function.