Why Atmos?

From mono to immersive

Mono: one channel
Stereo: an image between two speakers
Surround: speakers around the listener
Immersive: surround with height

Terms that get confused

A channel is a signal; a speaker is a transducer
Several speakers can reproduce the same mono channel
Surround describes a playback layout
Ambisonics represents a sound scene
Atmos combines channel beds, objects, metadata, and rendering

What Atmos contains

One or more channel-based beds
Mono or stereo objects with position metadata
Up to 128 input channels at 48 kHz
Up to 118 object inputs
A renderer for the target playback layout

Channel and object audio

Object tracks and bed tracks routing

Two panners in Logic

Bed and object panners in Logic Pro

Master files and playback encodes

Stage	Common format	Purpose
Music master	ADM BWF	Delivery to a label, distributor, or music service
Renderer master	DAMF, ADM BWF, or IMF IAB	Post-production, interchange, QC, and encoding
Consumer encode	Dolby Digital Plus with Atmos, TrueHD with Atmos, or AC-4	Streaming, disc, broadcast, or device playback
Cinema package	IAB in a DCP	Theatrical playback

Rendering is layout-aware

Objects retain position metadata until playback
Beds retain their channel assignments
The renderer uses the available speaker layout
Headphone playback uses a binaural renderer

Binaural monitoring

Dolby Renderer modes: Off, Near, Mid, Far
Apple Renderer: Music and Movie monitoring modes
Optional head tracking and personalized profiles on supported Apple devices

Where Atmos is used

Theatrical cinema and home video
Film and television streaming
Music streaming
Games and interactive media
Live broadcasts and sports
Automotive playback systems

DAW support

Pro Tools Studio and Ultimate: integrated or external Dolby Atmos Renderer
Nuendo: internal Atmos authoring with external-renderer support
Logic Pro: built-in Dolby Atmos plug-in and ADM BWF export

Dolby Atmos Composer

fiedler-audio.com/dolby-atmos-composer/
Atmos authoring in DAWs with limited multichannel routing
Beam plug-in for audio and object positioning
ADM BWF import and export
Optional OBAM processing on the Atmos master channel

Other immersive formats

MPEG-H Audio: channels, objects, scenes, and listener interactivity
IAMF: an open, codec-agnostic immersive-audio specification
Eclipsa Audio: a Samsung and Google implementation based on IAMF
ASAF and APAC: Apple’s production format and delivery codec

Questions to carry forward

Does this sound belong in the bed or in an object?
Which renderer will the audience hear?
Which alternate renders need QC?
What master does the recipient require?

References