Siberia 800 has multiple input and output connections that were selected for different reasons. The USB connection was selected for plug-and-play connection to PC, Mac, and consoles chat. That said, while USB is a familiar connection, it’s not the best choice for surround sound on Siberia 800 because it carries two-channel (stereo) audio and not multi-channel sound. For this reason, SteelSeries strongly recommends using the optical connection for the best Dolby surround experience when it is available.
The Optical Input on the Siberia 800 transmitter box provides the best sound quality as well as Dolby Digital surround sound. You should use the optical connection for all consoles and computers that have an optical audio output. The optical port is a small door with a red light inside. In addition to Optical, it might be labeled S/PDIF, TOSLINK, or Digital.
If your console or computer does not have an optical audio port and you connect your console to your TV using an HDMI cable, then you can take digital audio out of most TVs’ optical connection and Dolby Digital surround sound will be supported.
If you do not have an optical output on your console, TV, or computer, then you should use USB, which still provides high quality digital audio and Dolby Headphone and Dolby Pro Logic IIx surround sound. These technologies virtualize surround sound from the two-channel feed, whereas Dolby Digital uses the full multi-channel signal to create its surround soundscape.
A little-known tip is that many computers have an optical audio output on the headphone port. Many people do not realize this since it looks just like it is just a headphone port. This is true of many gaming PCs and most recent Mac computers. If your computer has a combination optical/headphone port, it can be used for optical audio using an inexpensive mini-TOSLINK adapter and will provide the same 7.1-channel Dolby Digital surround sound as on a console or home entertainment system. If your sound card has a coaxial digital output, you can convert it to optical using a Coaxial (In) to Optical (Out) Digital Audio Converter.