Is audio better through USB or optical?
Both will work fine, but optical has some major benefits over USB that just pushes it into first place. Not being affected by electrical and radio interference is a major advantage to me in the audio world. Personally I always use optical audio when possible.
What does an optical adapter do?
An optical digital audio connection sends stereo or 5.1 S/PDIF digital audio between devices. An everyday use for this type of connection is the digital audio output on the back of your TV. By connecting this output to an amplifier, you can quickly improve the sound of your television.
How do I connect optical audio to my computer?
Most computers don’t offer an optical/SPDIF output, but if yours does, all you have to do is plug an optical cable into it, then plug the connector on the other end to the sound bar’s optical input (circled in red in the illustration below).