What Is Dolby Atmos Immersive Surround Sound?

Immerse yourself in a cocoon of sound with Dolby Atmos

Dolby Atmos is a surround sound format introduced by Dolby Labs in 2012. It's the total sound immersion experience you hear in a commercial cinema environment. It provides up to 64 channels of surround sound by combining front, side, rear, back, and overhead speakers with a sophisticated audio processing algorithm that adds spatial information.

Dolby partnered with several AV receiver and speaker makers to bring the Dolby Atmos experience to home theaters following its initial success in cinemas. Dolby Labs provided these manufacturers with a physically scaled-down version that is suitable and affordable to most people.

Klipsch Dolby Atmos Speaker Setup
The Klipsch Group

Dolby Atmos Basics

Many home theater receivers have surround-processing formats, such as the Dolby Prologic IIz and Yamaha Presence. Because of this, you can add a broader front sound stage, and Audyssey DSX can fill in the side sound field. However, as sound moves from channel to channel and overhead, you may experience sound dips, gaps, and jumps. Now the sound is here, and then the sound is there.

Pioneer VSX-933 Dolby Atmos Home Theater Receiver
Pioneer Electronics

For example, when a helicopter flies around the room or Godzilla wreaks havoc, the sound may appear wobbly rather than smooth like the filmmaker intended. You may not experience a continuous wrap-around sound field when there should be one. Dolby Atmos fills in those surround sound gaps.

Spatial Coding

The core of Dolby Atmos technology is Spatial Coding (not to be confused with MPEG Spatial Audio Coding), in which sound objects are assigned a place in space rather than a specific channel or speaker.

Upon playback, the metadata encoded within the content bitstream (such as a Blu-ray disc or streaming movie) is decoded on the fly by the Dolby Atmos processing chip in a home theater receiver or AV processor. The receiver or processor makes the sound object spatial assignments based on the channel or setup of the playback equipment.

Setup

If you have a Dolby Atmos-enabled home theater receiver or an AV processor and amp combination, the menu system asks these questions to help you set up the best Dolby Atmos listening options for your home theater:

  • How many speakers do you have?
  • What size are the speakers?
  • Where are the speakers located in the room?

EQ, Room Correction Systems, and Height Channels

Dolby Atmos is compatible with existing automatic speaker setup, EQ, and room correction systems, such as Audyssey, MCACC, and YPAO.

Height channels are an integral part of the Dolby Atmos experience. To gain access to height channels, install speakers mounted on the ceiling or employ two new types of convenient speaker setup and placement options:

  • Add after-market speaker modules that rest on top of your current front left/right and surround speakers.
  • Add a speaker with both front and vertically firing drivers encased within the same cabinet.

The vertical driver in these two options directs sound that ceiling-mounted speakers typically produce to the ceiling, reflecting the listener. If appropriately placed concerning a low flat ceiling, there's little difference between this type of speaker design vs. using separate ceiling-mounted speakers.

Although the all-in-one horizontal/vertical speaker reduces the number of individual speaker cabinets, it doesn't mitigate speaker wire clutter. You must still connect the horizontal and vertical channel drivers to separate speaker output channels from the receiver.

The eventual solution might be self-powered wireless speakers, such as that provided by Damson.

Hardware and Content Availability

Dolby Atmos is compatible with current Blu-ray and Ultra HD Blu-ray Disc format specifications, and there's plenty of content available. Dolby Atmos-encoded Blu-ray Disc is also playback-backward compatible with most Blu-ray Disc players.

To access the Dolby Atmos soundtrack, the Blu-ray Disc player needs HDMI version 1.3 or newer outputs, and you must turn off the player's secondary audio output setting. You must use a Dolby Atmos-enabled home theater receiver or AV processor as part of the chain.

Secondary audio is usually where things such as the director's commentary are accessed.

Dolby TrueHD and Dolby Digital Plus

Dolby Atmos metadata fits within the Dolby TrueHD and Dolby Digital Plus formats. If you can't access the Dolby Atmos soundtrack, as long as your Blu-ray Disc player and home theater receiver are Dolby TrueHD or Dolby Digital Plus compatible, you have access to a soundtrack in those formats, if the disc or content includes them.

Since Dolby Atmos can be embedded within a Dolby Digital Plus structure, Dolby Atmos can be used in streaming and mobile audio applications.

Processing for Non-Dolby Atmos Content

To provide a Dolby Atmos-like experience on currently available 2.0, 5.1, and 7.1 content, a Dolby Surround Upmixer that borrows on the concept employed by the Dolby Pro-Logic audio processing family, is included in most Dolby Atmos-equipped home theater receivers. Look for this feature.

Dolby Atmos Speaker Placement Options

There are four things you need to access the true Dolby Atmos experience:

  • A Dolby Atmos-equipped home theater receiver, soundbar, or smart speaker.
  • A Blu-ray or Ultra HD Blu-ray Disc player (most recent model Blu-ray Disc players compatible) or a compatible streaming player.
  • Dolby Atmos-encoded Blu-ray disc or streaming content.
  • More speakers.
Dolby Atmos Speaker Setup Examples
Onkyo / Dolby Labs  

Oh No! Not More Speakers!

If home theater speaker configurations weren't complicated enough, you might want to buy a large spool of speaker wire if you plan to enter the world of Dolby Atmos. When you thought you could handle 5.1, 7.1, and 9.1, you may now have to get used to some new speaker configurations, as shown in the above photo, such as 5.1.2, 5.1.4, 7.1.2, or 7.1.4.

Here's what the 5.1.2, 5.1.4, 7.1.2, and 7.1.4 designations mean:

  • The 5 and 7 represent how the speakers are generally configured around the room in a horizontal plane.
  • The .1 represents the subwoofer. In some cases, the .1 might be .2 if you have two subwoofers.
  • The last number designation represents ceiling speakers. The above examples would refer to setups with either two or four overhead speakers.

Easy-to-Add Speaker Solution Possibilities

Dolby Atmos typically requires adding extra speakers. Dolby and its manufacturing partners have come up with some solutions that may not mean you have to hang or place speakers inside your ceiling physically.

One solution available is small Dolby Atmos-compatible vertically firing speaker modules. In your current layout, these modules can be on top of the front left/right and left/right surround speakers. It doesn't get rid of the extra speaker wires. Still, it makes it more attractive than running speaker wire up your walls or having to go into the walls.

Another option is speakers that include horizontally and vertically firing drivers in the same cabinet. This setup is practical if you're building a system from scratch or switching out your current speaker setup. It also decreases the physical number of speaker cabinets needed. However, it doesn't necessarily cut down on the number of speaker wires you need.

The speaker module or all-in-one horizontal/vertical speaker system work because the vertically firing speaker drivers are highly directional. This system enables the speakers to project sound that bounces off the ceiling before dispersing into the room.

It creates an immersive sound field that appears to come from overhead. Most rooms that can fit such a home theater system have speaker-to-ceiling distances that would work.

Rooms with highly angled cathedral ceilings might be an issue. Vertical sound projection and ceiling reflection aren't optimal to create the best overhead sound field. For this scenario, strategically placed ceiling speakers may be the only option.

Home theater receivers equipped with Dolby Atmos are priced anywhere from $400 to $1,299 or $1,300 and up.

Dolby Atmos in Soundbars, Smart Speakers, and TVs

In addition to home theater setups requiring extra speakers, Dolby Atmos is being incorporated into select soundbars, smart speakers (such as the Amazon Echo Studio), and TVs (mostly select models from LG).

Yamaha YSP-5600 Dolby Atmos Soundbar
Yamaha

After Dolby Atmos source material is decoded or a non-Dolby Atmos content source is upmixed, a combination of up-firing speakers built into a soundbar cabinet in smart speakers and TVs is employed to deliver an immersive Dolby Atmos effect.

Although not as accurate as a Dolby Atmos system with added physical speakers placed around the room and on the upper wall or ceiling, it brings a more immersive surround sound experience for smaller spaces and budgets.

The Bottom Line

The big takeaway with Dolby Atmos is that it's a game-changer for home theater audio.

Starting with sound recording and mixing to the final listening experience, Dolby Atmos frees that sound from the current limitations of speakers and channels and surrounds the listener from all points and planes where sound can be placed.

From a bird or helicopter flying overhead, to rain falling from above, to thunder and lightning hitting from any direction, to reproducing the natural acoustics of exterior or interior environments, Dolby Atmos produces a highly accurate natural listening experience.

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