surround sound 
noun [mass noun]
A system of stereophony involving three or more speakers surrounding the listener so as to give a more realistic effect: [as modifier]: I am about to purchase a spangly new surround sound system for my living room...
- The best gaming PCs come with a complete 5.1 speaker system for true digital surround sound.
- An entertainment system with surround sound can transform this room into a home theater.
- No benchmark could ever provide a definitive evaluation system for surround sound.