Understanding Home Theater Sound Types: More 7.1-Channel Formats

Here on the Home Theater Installation Orange County blog, we’re in the middle of a series explaining the various aspects of home theater sound. There are so many types and technologies that it can be hard for many people to keep up. We’re here to help with this multi-part guide.

Last week we looked at the two main 7.1-channel formats, Dolby TrueHD and DTS-HD Master Audio. We also covered what makes 7.1 different than 5.1: the two additional rear surround speakers, for a total of 7 channels plus a subwoofer.

This week we’re rounding out the 7.1 category with three other sound types.

Dolby Pro Logic IIx

If you remember back a couple weeks, we talked about some formats that do something called upmixing. These formats take a stereo signal and upmix it to take advantage of all 5.1 channels. Well, Dolby Pro Logis IIx is the next iteration of upmixing. Systems equipped with this codec can take audio content that’s encoded as stereo or as 5.1 and distribute that sound across all 7.1 channels.

This format is useful when playing older media or stereo-encoded audio CDs.

Dolby Digital Plus

This format is the successor to Dolby Digital 5.1. It does what Dolby Digital does, but over all 7.1 channels. It’s slightly inferior to Dolby TrueHD in that Dolby Digital Plus is lossy. (Though again, if you have average ears and average equipment, you’ll rarely notice a difference.)


This technology is DTS’s answer to Dolby Digital Plus. It’s a 7.1-channel upgrade to DTS’s 5.1-channel technology. It, too, is lossier than its fancier sibling, DTS-HD Master.


When selecting new 7.1-channel audio equipment, the smart play is to go for equipment that can process all of these formats. The media you want to play will be encoded various ways, and you don’t want to be held back by an unsupported format.

Talk to one of our specialists today to make sure you’re getting everything you need for your new system.


Understanding Home Theater Sound Types: Dolby Atmos and DTS:X

We’ve finally arrived at the conclusion of our series on Understanding Home Theater Sound Types. It’s been our privilege here at Experience Audio Video to educate you, our readers, on this often confusing topic. Thanks for reading!

So far we’ve covered all the major home theater sound types in the 5.1-channel, 7.1-channel and 9.1-channel categories. But there’s one more category that bears discussing: the current undisputed champion of fully immersive audio, 11.1-channel formats.

There are three 11.1-channel formats to discuss, all evolutions of technologies we covered in previous posts.

Dolby Atmos

Dolby Atmos is a real reimagining of surround sound technology. It’s an object-based format, where audio is assigned to exact spatial locations, mimicking where those sounds would take place if your media were real life. It includes either ceiling-mounted speakers or up-throwing speakers to generate the spatial element.

With Atmos, you need a new number in your configuration: 7.1.4, for example, indicates a seven-speaker surround setup, one subwoofer, and four overhead or up-firing speakers.


DTS:X takes a similar object-based approach, but it’s a little more flexible. It works with or without the overhead/up-firing speakers, so you could use DTS:X with as little as a 5.1-channel configuration. It also allows for some mild customization, such as toggling dialog louder.


Auro-3D has several additional configurations and speaker placements, including a 10th channel overhead center and an 11th, which adds front center height.

Auro even has a 13.1-channel option, which adds in the rear surround left/right speakers that were lost way back at 9.1-channel Auro-3D. Note that there are very few 13.1-channel receivers on the market, and like any latest and greatest tech, you’ll pay a premium.

Which Should You Choose?

Much of today’s content is encoded with either Dolby Atmos or DTS:X. The good news is that most robust systems can adequately interpret both of those without the need for reconfiguration. Auro-3D is a bit different, but it can adequately distribute content encoded using the other formats as well.

Unsure which way to go? Schedule a free consultation today and talk to an industry veteran to help determine what makes the most sense for your space.


Understanding Home Theater Sound Types: Auro-3D and Dolby Pro Logic IIz

We’ve been talking about home theater sound formats for the last several weeks on the Home Theater Installation Orange County blog. We’re getting close to the end of this series now. So far we’ve covered all the major 5.1-channel and 7.1-channel formats, and we’ve shared a bit of a tutorial on what those designations are all about.

If you’re just joining us, we highly recommend you read the previous posts in the series before continuing.

9.1: The Next Frontier

For many consumers, a 5.1- or 7.1-channel system will meet their expectations and create a perfectly enjoyable home theater experience. But some of you want even more. The next evolution in home theater sound is 9.1-channel audio.

As you might expect, 9.1-channel configurations add two additional channels, which correspond to two additional speakers. One great thing about 9.1-channel formats and equipment is that both formats can automatically upmix any source to utilize all the speakers in your system.

Let’s look at the two 9.1-channel formats on the market today.

Dolby Pro logic IIz

Dolby’s 9.1-channel format can upmix any source, adding front height effects to what would otherwise be a 7.1-channel sound. These front height speakers are the two new channels, and they are placed high on the wall above your front left and right speakers. They add further depth and dimension to your sound.


Auro-3D takes a slightly different approach. Remember those additional rear speakers we gained when we bumped up to 7.1? Auro-3D ditches those in favor of a “full 3D” soundscape. With Auro-3D, you add height speakers (up high on the wall) above your front left and right as well as your surround left and right. In a way, you’re sacrificing a bit of surround immersion, but the trade-off is a much greater sense of 3D sound immersion.


Understanding Home Theater Sound Types: Dolby Digital (plus DTS)

One of the main components of a home theater setup is the sound system. Generally to qualify as home theater, a system needs to have some form of surround sound.

The only problem? There are so many different formats and setups for home theater sound. It’s enough to make your head spin!

That’s why we’re starting a new series on the Home Theater Installation of Orange County blog today: Understanding Home Theater Sound Types. We’ll start today with one of the earliest formats that’s still in wide use: Dolby Digital.

Prologue: Defining Terms

Before we dive into Dolby Digital, we need to define some terms. In the world of home theater speaker setups, you’ll often see numbers, like 5.1 or 7.1, in addition to branded names, like Dolby Digital or Atmos. Both of these are important. We’ll cover the branded names later on, but first let’s look at the numbers.

If you see a number like 5.1 or 7.1, you’re seeing a shorthand description of the number of speakers. A 5.1 system has five distinct speakers, plus a subwoofer (that’s the .1).

Whatever numbers are associated with your speaker system, you’ll also need a receiver that can handle that many channels of audio. So a 5.1 system needs a five-channel receiver, and a 7.1 system needs a seven-channel receiver.

Dolby Digital: The OG Surround Format

Dolby Digital is the original surround sound format. It was the first to provide clear, realistic multichannel audio in a 5.1 channel configuration (Front left/center/right and rear left/right). When used on discs (such as DVDs), audio must be compressed. The receiver then decompresses and plays the audio.

This compression isn’t particularly desirable among enthusiasts, but everyday folks probably won’t hear a difference—especially on non-premium speakers.

Bonus Format: DTS

DTS is a less common format in the same family as Dolby Digital. It improves on Dolby Digital by lowering compression levels. The difference is slight, however.

Interested to learn more? Stay tuned! We’ll cover many other formats in the weeks to come.