Adds two extra side speakers to the 5.1 setup for better spatial accuracy in larger rooms.
The numbers tell you how many "points of audio" you have. The first number is the speakers, the second is the subwoofers, and the third is height channels. buy surround sound
Modern buyers typically choose between these two paths based on space and complexity: Beginner's Guide to Surround Sound Setups - Sonos Adds two extra side speakers to the 5