GoKawiilTraditional surround sound systems incorporate five or more channels along the horizontal plane, including at least two behind you, as well as a bass channel from a subwoofer. This is referred to as 5.1 surround (the bass is the “.1”), 7.1 surround, and so on. These systems respond to surround sound mixes in TV shows and movies by spreading sound effects across each channel in order to provide a realistic sonic environment that corresponds with on-screen images to “surround” you in sound.
Dolby Atmos and rival 3D audio systems like DTS:X supplement traditional surround sound by adding a height element that spreads sound effects not just across the horizontal plane, but also the vertical one to create what is referred to by Dolby and others as a “dome” or hemisphere of sound. A basic dolby atmos system offers 5.1.2 or 5.1.4 channels, with the extra “2” or “4” indicating the number of height channels.
Multi-component home theater systems usually employ a separate speaker cabinet for each represented channel, including speakers either mounted on the ceiling or designed to bounce sound from the floor off to the ceiling to represent the overhead height channels in Dolby Atmos and other 3D sound mixes.
Dolby Atmos soundbars use a similar design concept, including upfiring drivers and, for some, separate speakers for the surround sound elements, referred to as rear or satellite speakers. Others use a mix of digital signal processing, upfiring and side-firing drivers (often a mix of both) to bounce sound off your ceiling and walls. These systems can be very effective, but especially when it comes to rear surround sound channels, there's no substitute for real speakers placed behind you.