By Brett Crockett, Senior Director of Sound Technology Research
When we talk about Dolby Atmos®, we talk about it being object-based audio. You may think, “I don’t care about the technical details. Sound is sound, and I just want my movie to sound good.”
That’s understandable. And the bottom line is that movies in Dolby Atmos flat out sound great. The multidimensional sound of Dolby Atmos provides amazing richness and depth. You feel like you’re truly inside the story, with sound coming from all directions, including overhead. And you get that experience no matter where you experience a Dolby Atmos movie—in a cinema with dozens of speakers, in a living room with just seven, or over headphones on the Amazon Fire™ HDX 8.9 tablet.
But if you want to understand why Dolby Atmos is so flexible and adaptable to different environments, it helps to understand object-based audio and why it’s superior to traditional, channel-based sound.
The limits of channel-based audio
There’s no question that channel-based audio can produce great sound. But the format is fundamentally limited because it is created to play back on a specific type of speaker arrangement and doesn’t have the necessary information to deliver a fuller, richer sound if you expand your system.
If a movie is mixed in 5.1, for instance, it has just the information it needs to play back to five speakers, set in predefined locations, and one subwoofer. There’s no point in adding more speakers because the 5.1 mix doesn’t know what to do with them. If you don’t place your speakers in the “right” locations, your movies won’t sound quite right.
The fact that it’s object based makes Dolby Atmos much more adaptable because it’s not locked to a certain number of speakers. Instead, the object-based nature of Dolby Atmos gives the soundtrack a wealth of data about the sound in a scene.
In Dolby Atmos, each sound in a movie scene—a gunshot or a woman’s scream, for instance—can be an object. Filmmakers can precisely specify where those sound objects should originate and how they should move.
Dolby Atmos adapts
All that detailed information makes a Dolby Atmos soundtrack incredibly adaptable—it can literally scale from a huge movie theatre with hundreds of moviegoers to a mobile device playing for one person wearing headphones.
And that detailed data gives you an array of options for setting up a home theater. You can start with a small Dolby Atmos system with five speakers at ear level and two that produce overhead sound and get a great experience. But if you’re later able to splurge and create a home theater with anywhere up to 24 ear-level speakers and 10 overheads, the Dolby Atmos mix will be able to take perfect advantage of all those speakers.
You don’t have to buy different versions of a movie for those different home theaters. Any Dolby Atmos mix on Blu-ray Disc™ or streaming video includes all the information needed for both the small system and the supersplurge home theater.
And you don’t have to place your speakers in rigidly defined positions. If your room is an unusual shape, you can put your speakers where they make sense. A Dolby Atmos system will figure out the optimal way to use them.
I know that entertainment enthusiasts care most about how Dolby Atmos sounds, and I’m certain that they’ll be impressed when they hear a Dolby Atmos system. But I think it’s also comforting to know that the format that sounds so great now will be able to adapt and become even better as their home theaters grow and change. And that’s why object-based audio matters.
Learn more about Dolby Atmos sound technology.