Dolby Atmos is an object-based surround sound format that supports height channels, which means sound can come from above your head. It results in an even more immersive listening experience since, depending on your home theater setup, you can hear sounds coming from all directions. Many 4k Blu-rays and even some streaming services like Netflix support Dolby Atmos—but not all soundbars do. The ones that do tend to be more expensive than most, but if you're after a more natural listening experience, they're worth considering. Soundbars usually use up-firing speakers to simulate an illusion of height by bouncing the sound off the ceiling and back to the listener. It won't be as accurate or immersive as down-firing speakers with a more traditional home theater setup.