- Set up your Xbox 360 in the desired location and plug in the power adapter. Leave it and your Onkyo system off for now.
- Plug one end of the cord into your Xbox 360's HDMI out port, and plug the other end into your Onkyo's HDMI in port if using HDMI. Plug one end of the cord into your Xbox 360's optical audio out port, and plug the other end into your Onkyo's optical audio in port if using S/PDIF optical in an Xbox 360-S console. Plug your Xbox 360 A/V cable into the A/V port on your Xbox 360, plug the optical audio cord into the optical audio port on the A/V cable, then plug the other end of the optical audio cord into your Onkyo's optical audio in port if using S/PDIF optical in a non-Xbox 360-S console.
- Turn on your sound system, Xbox 360 and TV.
- Navigate to the "My Xbox" menu with your Xbox 360 controller, select "System Settings," go to "Console Settings," choose "Audio," then select "Digital Output." Your Xbox 360 will now output sound in full Dolby Digital.
How to Connect the Xbox 360 to an Onkyo Home Theater System
Onkyo is one of many companies that produce mid- to high-end home theater surround sound systems. Depending on your specific model and the features present, you probably will have either one or two options for connecting your Xbox 360 to it. Those options are via optical S/PDIF (digital audio only) and HDMI (HD video and digital audio). If your Onkyo receiver has one or both of these connections, simply choose the one that best suits your setup.