Hdmi to Dvi+Spdif/Headphone,HDMI to DVI + Coaxial Audio Video Converter Box Adapter with US Power Adapter for PS3,Blue Ray DVD

You likely want something like this. Or could go completely analog via this, if you’re only using the TV’s speakers (I wouldn’t expect there’d be any video quality loss with this type of cable). But your current setup may work as well. First thing to do is to go to the audio output settings on the Xbox and set the output to 2.0 LPCM. This should be the most basic and universally compatible audio format. If you are still experiencing the same no audio issue, then the converter/cable you currently have is the problem. If stereo PCM does work, then you might want to try Dolby Digital 5.1, but this won’t improve things all that much if all you’re running into the TV is L/R composite audio and using the speakers in the TV. The benefit of the first link I shared is that this can be an all-digital connection. You would go DVI to your TV, and use a 3.5mm to toslink cable to an AVR or the spdif input on your TV.