Dolby Atmos Explained

In late 2014 Dolby announced it would be bringing Atmos technology to home theater systems. But without living in a major market area like New York or Los Angeles, It's still difficult to experience Atmos at a local theater, let alone decide if it's worth investing in a home system. There are two main premises of Atmos. The first is overheard sound, provided by adding between 2 and 4 additional speakers to today's common surround setups. The second is the focus on sound "objects." Channels like left, right, center, and surround become less important as sound is no longer directed to specific speakers. Instead, Atmos uses a software model to place sounds (as objects) within a given 3D space, and speakers are activated accordingly. This results in more natural sounding surround effects, and seamless movement of sound through space.

Whether in a commercial or home setting, Dolby Atmos systems show their wow factor during moving overhead sound effects. Think of a helicopter flying around, or bullets whizzing over your head. To achieve this added realism, additional hardware is necessary on two fronts. First, is a surround processor capable of reading a Dolby Atmos audio stream. Next, are speakers designed to project overhead sound. Home users will need to upgrade to a new AV receiver that can decode Atmos sound, as well as source material that contains an Atmos audio track. Currently, there are around a dozen Bluray discs that are Atmos enabled (source: Big Picture Sound), as well as plans to bring Atmos to streaming services like VUDU and Netflix. If it isn't possible for home theater enthusiasts to add more speakers in their ceilings, they can take advantage of Atmos enabled floor standing speakers. These speakers have a traditional design on the front, but also add an upward facing driver for bouncing sound off the ceiling. When placed and tuned correctly, the effect from Atmos enabled speakers is very convincing. They approximate the motion based sound effects of commercial theaters quite well.

Atmos Enabled speakers with added ceiling facing drivers. 

Atmos Enabled speakers with added ceiling facing drivers. 

A lot of the magic of Dolby Atmos is happening behind the scenes, before it ever reaches our ears. Thanks to revolutionary software, Dolby has created a new way for sound engineers to interact with audio. It's now easier to achieve sound that filmmakers once only dreamed of because they can place effects as objects visually in a 3D space, as opposed to estimating which speaker channels should play at a given time. Alfonso Cuaron, director of Gravity, spoke highly of Dolby's new way of imagining sound by saying:

When I started mixing my films, I was always asking for possibilities in the mixing room that were not achievable, and now, finally, with this system that is Dolby Atmos, this dream came true. You really can explore the possibilities of depth and separation as never before.

Anyone who has seen Gravity knows that it is as much an immersive experience as it is a movie. It went on to win three Academy Awards for sound including: Best Sound Mixing, Best Sound Editing, and Best Music. So it seems that much of Atmos's power stems not only from the technology, but by allowing us to think differently about how moving sounds work. By imagining sounds as objects: like a helicopter, or a tornado, or the void of space, working with those sounds becomes much more intuitive. We can only hope that more filmmakers like Cuaron feel the same way, and continue to push Atmos's possibilities.

Placing sound objects within a 3D space is fairly intuitive with Dolby Atmos. On the right, sound objects are represented as yellow spheres.

Worth Upgrading?

All of this hype about Dolby Atmos begs the question, "Is it worth upgrading my home theater setup?" As long as Atmos enabled movies continue to be released regularly, the answer is a resounding yes. The combination of software and hardware provides a new level of depth and fluidity to big, effects filled movie scenes. Sound comes across as more natural in an Atmos setup, and helps create a more immersive experience.

For more information on Dolby Atmos, view Dolby.com