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Õ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøDOLBYÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøDolby Atmos for the Home TheaterOctober 2016Õ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍø씨լàËÍøÕ¬àËÍøÕ¬àËÍøÕ¬àËÍøDolby Atmos,the revolutionary cinema sound technology,has come to home theaters,bringing anew and exciting sense of total immersion and reality to your favorite movies,music,video games,andother programming.In simple terms,Dolby Atmos is the most exciting development in homeentertainment since the introduction of surround sound more than 20 years ago.With Dolby Atmos,content creators now have the tools to precisely place and move sounds anywhere in your living room,including overhead,to make entertainment incredibly immersive and lifelike.This white paper explains how Dolby Atmos will work in home theaters and how you can build a DolbyAtmos enabled system or upgrade your existing system to support Dolby Atmos.It also explains thetechnological components of Dolby Atmos in home theater and the tools that content creators andbroadcasters use to create and deliver Dolby Atmos content to homes.New advances in speaker designand audio/visual receiver (AVR)processing help bring this powerful new audio experience to the hometheater.Why replace channel-based surround sound?Dolby Atmos is a revolutionary technology that moves beyond the paradigm of channel-basedaudio,which has reached its maxim potential in the home entertainment spaceDolby has led in the advancement of home theater technologies since the late 1980s,when weintroduced four-channel Dolby Pro Logic.We pioneered the development of discrete 5.1 surroundsound and then introduced 7.1 surround sound in the home and the cinema.But as home theaterexpanded to 9.1 and even 111 systems,the problems of pursuing more and more channels becameclear.Home theater content often originates from theatrical content that is mixed,at best,in 7.1 soundand many times in 5.1 That meant that 9.1 or 111 systems reached a point of diminishing returns inparsing and upmixing that limited the signal to serve more and more channels.In addition,the ability to recreate reality using channel-based audio is inherently limited.In real life,sounds move in specific and sometimes complicated ways-a hummingbird flies from a tree branch,hovers in front of a pair of blossoms,and then dives down to a fountain for a drink.Simply moving thehummingbird's sound from the Left Height channel to the Right Front channel can't possibly recreatethe detail of that bird's flight.And when you lose those details,it detracts from the brain's sense thatwhat it's watching is real.A cinema solutionDolby started investigating solutions to the problems of channel-based audio in the cinema.Our goalwas to free filmmakers from the limitations of channel-based audio by developing a system thatallowed them to determine exactly where a sound should be and where it should move in threedimensions-that is,to faithfully recreate that hummingbird's flight in all its complexity.We worked closely with filmmakers and sound mixers to perfect the technology.Renting out entiremovie theatres to use as laboratories,Dolby engineers worked hand in hand with sound mixers,adapting their inputs into what would ultimately become the tool set that enabled mixers to createcompelling Dolby Atmos object-based soundtracks.The result of that intense collaboration,Dolby Atmos,debuted in June 2012 in the movie Brave.Sincethen,all the major Hollywood movie studios have embraced the technology.Dolby Atmos has beenadopted by the cinematic community worldwide,with more than 500 movies already released or inproduction and more than 150 mixing facilities to date enabling this new creativity in filmmaking.Dolby Atmos and sound objectsDolby Atmos is based on the concept of sound objects.In the cinema,Dolby Atmos relies on acombination of 9.1 "bed"channels and up to 118 simultaneous sound objects to deliver an envelopingsound stage.Every sound in a scene-a child yelling,a helicopter taking off,a car horn blaring-can bea separate sound object.Each of those sounds comes from a specific location in the scene,and in somecases,they move.The car careens from left to right,while the yelling child runs up a set of stairs.Using sophisticated content creation tools that represent the sound objects in a three-dimensionalspace,filmmakers can isolate each of the sound objects in a scene and decide exactly where they wantthem to be and how they want them to move.In the final sound mix,the sound objects are combinedwith positional metadata-additional data that describes a number of parameters about the soundobject,including its location and movement,if any.Õ¬àËÍøFigure 1:Filmmakers use this tool to manipulate sound objects in a three-dimensional space.Dolby Atmos in home theaterDolby has developed the technology required to translate the Dolby Atmos experience in cinema tohome theaters.In the case of the home theater,every sound in the mix is represented as an audioobject.When you set up your Dolby Atmos enabled AVR,you inform your receiver how many speakersyou have,what type of speakers they are(large,small,overhead,and/or Dolby Atmos enabled),andwhere they're located.Armed with this information,a sophisticated processor in your AVR-the ObjectAudio Renderer or OAR-analyzes the positional metadata and scales each audio object for optimalplayback through the connected speaker system.This process include includes determining in real timeexactly which speakers it needs to use from moment to moment in order to reproduce the sounds ofthe car careening across the screen and the child fleeing up the stairs.That detailed,very specificmovement of sound helps your brain suspend disbelief and feel as if what you're watching is real.3