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Understanding Dolby Surround Sound for Home Theaters

How to set up Dolby Atmos® Speakers

You can enjoy cinema-quality sound in your own home with Dolby Atmos. Engineered to direct sound upward, Dolby Atmos-enabled speakers reflect the sound off the ceiling.

For overhead sound by Dolby, you can either use ceiling speakers, Dolby Atmos-enabled speakers, or a Dolby Atmos-enabled soundbar, which significantly upgrades the sound over a television’s built-in speakers without having to install multiple speakers in various spots in a room.

Dolby Atmos-enabled speakers are available as either integrated units with forward-directed speakers or as add-on modules with upward-directed speakers. You can use two Dolby Atmos-enabled speakers, but four are recommended for an optimal listening experience. Setting up four speakers instead of two will result in sound that is richer, more precise, and more realistic.

Dolby Atmos® is the latest sound effect system from Dolby, it adds height effects on top of the regular Dolby system’s left, center, right and surround effects. So you will hear more dimensional sound effects.

What’s the best and easiest way to add Dolby Atmos® sound?

According to Dolby Atmos® spec, you will add height effects on top of typical left, center, right and surround. The best and easiest way is to add ceiling speakers to the height effect setup.

It is directly firing down and has better control on sound effect than the firing up setup which has to use the ceiling to reflect the sound. Pictured is a Dolby Atmos: 7.1.4 setup which uses an 11.2 Receiver system with four overhead(in-ceiling) speakers.

How is Dolby Atmos® different from typical channel-based home theater systems?

Dolby Atmos is the first home theater system that is based not on channels, but on audio objects. What is an audio object? Any sound heard in a movie scene—a child yelling, a helicopter taking off, a car horn blaring—is an audio object. Filmmakers using Dolby Atmos can decide exactly where those sounds should originate and precisely where they move as the scene develops.

Thinking about sound in this way eliminates many of the limitations of Channel-based audio. In a channel-based system, filmmakers have to think about the speaker setup: Should this sound come from the left rear surrounds or the left side surrounds?

With Dolby Atmos, filmmakers just have to think about the story: Where is that yelling child going to run?

The Dolby Atmos system, whether in the cinema or a home theater, has the intelligence to determine what speakers to use to precisely recreate the child’s movement in the way the filmmakers intend.

Dolby Atmos is also far more flexible and adaptable than channel-based home theater. In a channel-based system with channel-based content, the number of speakers is fixed—a 7.1 system always consists of seven speakers and one subwoofer.

With Dolby Atmos, in contrast, you have amazing flexibility: you can get the full experience with just seven speakers or get an even richer, more detailed sound by adding more speakers. As you add speakers, a Dolby Atmos-enabled receiver will automatically determine how to use them to create fantastic, immersive audio.

If Dolby Atmos allows me to add more speakers, why do I see A/V receivers with just 11 channels?

Many hardware partners are building or planning to build Dolby Atmos enabled A/V receivers and speakers. Those partners decide what product configurations make the most sense for their customers. But the Dolby Atmos system itself is almost unlimited.

If you have space and budget, you can build a Dolby Atmos system with as many as 24 speakers on the floor and 10 overhead speakers. One of our hardware partners is planning to release an A/V receiver with 32 channels.

Do I have to install speakers in my ceiling?

In real life, sounds come from all around us, including overhead. Having the ability to recreate overhead sounds is a key element in making Dolby Atmos sound so realistic.

The obvious way to create overhead sounds is to install speakers in or on your ceiling. And all of our ceiling speakers can satisfy the needs of the Dolby Atmos application. But if you already have conventional speakers you like, you can simply buy ceiling speakers and install them on the top of your listening area.

How many overhead speakers do I need?

For the best Dolby Atmos experience, we recommend four overhead speakers for most homes. But you can get a great sound with just two. The picture below is the 5.1.2 Overhead Speakers (in-ceiling speakers).

  1. Seating Position
  2. Left and Right Front Speakers
  3. Center Speaker
  4. Subwoofer
  5. Left and Right Surround Speakers
  6. Left and Right Overhead Speakers

Will I have to replace my Blu-ray player or my HDMI cables?

Any Blu-ray player that fully conforms to the Blu-ray specification can play a Dolby Atmos movie without a firmware update. Just remember to set your player to audio bit-stream output mode. There’s also no need to buy new HDMI® cables. The current HDMI spec fully supports Dolby Atmos audio.

Dolby Atmos speaker setup, what do these numbers mean like “5.1.2”?

5 – This refers to the number of traditional surround speaker (front, center, rear surround)

1 – This number refers to how many powered subwoofers you can connect to your receiver

2 – This refers to how many overhead or Dolby Atmos-enabled speakers you can use in your Atmos setup.

Why do we recommend down-firing (in-ceiling) speakers setup over upward-firing speakers setup?

As you can see in the picture above, that upward-firing speaker setup has to fire up the sound and use your ceiling to reflect the sound back to you, which is not efficient and you may lose some sound when it bounces back from your ceiling.

Your ceiling may not be perfectly flat or has materials that are absorbing the sound. Plus the box upward-firing speakers are more expansive than the ceiling speakers and take lots of useful space in your home theater room.

The down-firing setup uses in-ceiling speakers to directly produce the high effect sounds so it is better to control, direct, and correct sound.

If you want to get started with a Dolby sound system, contact our audio experts today!