The LS30/31 will only accept stereo PCM input from the optical input. If the console is set to output DTS or Dolby Digital surround sound, a digital noise/static will be heard.
Follow these steps from the User Guide to ensure that the console is set to output only stereo audio on the optical connection:
On the Xbox One, go into Settings > General > Volume & audio output. Under ‘Audio Output’ select ‘Optical audio’ and choose ‘Stereo uncompressed.’
Go into Settings > Sound and Screen > Audio Output Settings > Primary Output Port and select ‘Digital Out (Optical)’.
Make sure that only ‘Linear PCM 44.1kHz and ‘Linear PCM 48kHz’ are checked.
Go into Settings > System > Console Settings > Audio and select ‘Digital Stereo’.
Go into Settings > Sound Settings > Audio Output Settings > Optical Digital.
Make sure that only ‘Linear PCM 2 CH. 44.1kHz’ and ‘Linear PCM 2 CH. 48kHz’ are checked.