Dolby Atmos vs Dolby Digital: Differences, Uses

Dolby Atmos

A lot of people have been asking questions regarding the difference between Dolby Atmos and Dolby Digital. 

Some are now wondering if they should upgrade to a home theater receiver that supports only Dolby Atmos or one that also has Dolby Digital as well.

In this article, we’re going to provide a detailed comparison between both technologies. 

To do so, we’re going to compare their differences, specifications, and how these two technologies affect movie playback in your home theater.

First, though, let’s start by going over what each technology is and where you’ll be able to find it.

What Is Dolby Atmos?

Dolby Atmos is a surround sound technology found on Blu-ray discs and 4K Ultra HD Blu-rays that boosts the dynamic range and use of surround sound speakers. It was first introduced back in 2012 by Dolby Laboratories and has since then become a standard for the latest home theater receivers and soundbars.

Dolby Atmos is meant to be played back with overhead or upward-firing speakers which create an immersive 3D effect on your home theater system. On some A/V receivers, you can also find height channels as well (these speakers will fire upwards but not necessarily from the ceiling). 

This technology fills your room with sounds all around you regardless of where they’re coming from; it truly makes you feel like you’re inside a movie theater.

What is Dolby Digital?

Dolby Digital is a surround sound technology that is also found on Blu-ray discs and 4K Ultra HD Blu-rays. It’s a fairly old technology as it was first introduced back in 1997 but is still being used today because of its standardization for high-quality audio amongst the industry. 

Unlike Dolby Atmos, Dolby Digital doesn’t require height or upward-firing speakers to work because all channels are meant to be played through your front, center, and surround sound speakers which you have already set up from previous home theater setups.

How Does Dolby Atmos Work?

Now that we’ve provided a basic understanding of what each technology is, let’s dive into how they both work.

Dolby Atmos is a highly sophisticated audio standard for your home theater system that requires special speakers to work.

To be more specific, you’ll need speakers that have special drivers called “multiple transducer arrays” and these allow the sound waves from the speaker to bounce off the ceiling and back down into your room.

Even though Dolby Atmos can technically work on non-Atmos AV Receivers, we recommend getting an A/V receiver that has built-in Dolby Atmos decoding because it will provide higher quality audio (especially if you get one with upfiring or height speakers).

Dolby atmos

On top of having multiple transducer arrays, there are also two additional specifications you look out for when shopping for a new receiver or soundbar: Dolby Atmos Height Speaker Support and Dolby Atmos Decoding.

A home theater receiver that supports “height speakers” will usually have an additional 2nd zone of speakers on the top (this is where you can add in-ceiling or upward-firing speakers).

Also, a home theater receiver that has Dolby Atmos decoding means that it’s able to decode more layers of information within your Blu-ray Discs and 4K Ultra HD Blu-rays which gives you an even more immersive surround sound experience.

Dolby Digital on the other hand doesn’t exactly require different types of speakers to work because all channels are meant to be played through your front, center, surround sound speakers. 

The only difference is that a Dolby Digital soundtrack has extra information from the sound mixer encoded into it that tells your receiver how to decode it.

However, although a Dolby Digital track doesn’t require special speakers to work, having a home theater receiver with “Dolby Digital Plus” decoding can improve the quality of your audio because it allows for more channels and room for even more sound information which will enhance the dynamic range within your movie. 

This is why we recommend getting a home theater receiver with this technology on board as well if possible because it’s another layer of information being decoded on top of what you have already.

ParametersInitial costSpeaker placementSound creationPrimary system
Dolby Digital PlusHighHorizontal2DSpeaker based
Dolby AtmosHighHorizontal and Vertical3DObject-based
DTSHighHorizontal2DSpeaker based
StereoComparatively lowHorizontalN/ASpeaker based

What Is The Difference Between Dolby Atmos And Dolby Digital?

Now that we’ve gone over how each technology works, let’s compare the two by looking at their similarities and differences.

Similarities: Both formats are supported on 4K Ultra HD Blu-rays and standard blu-ray discs   Both Dolby Atmos and Dolby Digital have “firing” or “height” speakers Either technology can be used without an external amplifier (A/V Receiver). 

Differences: A home theater receiver with Dolby Atmos decoding is required for Dolby Atmos to work while a home theater receiver that has built-in Dolby Digital Plus is required for all types of surround sound including Dolby digital 5.1, Dolby digital 7.1, Dolby Digital +, Dolby TrueHD, etc. 

If you’re using more than one speaker system (front, center, surround sound speakers) then you need a home theater receiver that supports “height” or “ceiling” speakers for Dolby Atmos to work. An amplifier or soundbar is required if you want to use Dolby Digital 5.1 because the blu ray disc player will not produce enough power for your speakers.

What Is The Difference Between A Home Theater Receiver With Built-In Dolby Atmos vs Dolby Digital?

A home theater receiver with built-in Dolby atmos technology is great because it provides an enhanced audio decoding process along with its traditional surround sound capabilities.

For example, let’s go back to our previous example where we had two different Blu-ray discs playing: one that was Dolby Atmos and one that was Dolby Digital Plus. 

The difference is that with a home theater receiver that supports “height” speakers, you would be able to hear the sound moving above you as well as around your room (this can vary depending on how many speakers are available).

On top of having more speaker channels and audio layers being decoded, an A/V receiver will also have other neat features like power amplification for your speakers built-in Bluetooth connectivity (if it doesn’t already have wi-fi and ethernet). Even USB connectivity so you can playback music from your phone or iPad through your home theater system.

In conclusion, whether or not a home theater receiver has built-in Dolby atmos or Dolby digital plus technology, they both do the same thing and support all types of surround sound.

The only difference is that a home theater receiver with built-in Dolby Atmos decoding can produce a more dynamic and immersive experience because it has more information available for you to use.

What is Dolby Digital Plus?

As we were previously mentioned, there are several different types of surround sound codecs such as DTS, TrueHD, DTS- High-Resolution T technology y, AC3.

Dolby Digital Plus (DD+) is technically one of these surround sound formats but not many people know what it actually is and how different it is from other surround sound technologies.

While a home theater receiver with built-in Dolby Atmos or Dolby digital plus technology does the same thing, it is important to note that Dolby Digital Plus requires less bandwidth so it can be used for Blu-ray discs and streaming movies from services like Netflix at lower resolutions.

At this point, you might be wondering what’s so great about using Dolby Digital Plus? Well, since it can use a lower resolution signal to deliver high-quality surround sound, not only will your favorite streaming shows have a more immersive experience but your blu-ray movies as well. 

For example, a 1080p movie that has DD+ audio encoded into it will work fine on a 1080p capable display while a 4K tv that is Dolby Atmos capable can still work with a blu-ray disc that has Dolby Digital Plus audio encoded into it because the 4K tv will upscale a 1080p signal.

A blu ray player or home theater receiver may have ” 5 . 1 / 7 . 1 / Atmos/ DTS: X ” on the back of it but how do you actually know if there are height speakers built-in?

Unfortunately, this is where things can get confusing because even though these types of surround sound technologies all seem very similar, they are not equal. 

The only way to be sure which one your equipment supports is to read the user manual. If you notice that your home theater system has several speaker terminals then it may support Dolby Digital Plus. 

If it has ” 8 or more speakers ” then that means that your system also supports Dolby atmos as well because Dolby atmos can support up to 32 different speaker locations.

Conclusion

Even though Atmos may not be perfect (and probably never will), the fact remains that so far I have been extremely impressed with it from a practical standpoint. 

Playing back multichannel music material in Dolby Atmos has been very pleasant and enjoyable so far, much more so than anticipated. In fact, movies have almost felt secondary during these test sessions. 

So for those of you who are still on the fence about ditching traditional 5.1/7.1 multichannel playback, I would urge you to give Atmos a chance because it may just change your tune, especially if you value that “WOW” factor when demo’ing new gear to family and friends.