More complex audio systems build on the 2.1 system and add additional channels to create a 360 - degree envelope of sound around the listener. (howtogeek.com)
These boxes also act as a more comprehensive multimedia solution, thanks to the Android TV operating system built into each. (techradar.com)
Some cars have this type of system built in, but they're expensive and used in very niche products. (cnet.com)