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The ultimate surround sound guide: every format fully explained



It was the summer of '69. We are not talking about the song by Bryan Adams here; we actually refer to the first time surround sound became available at home. It was called Quadraphonic Sound and it first appeared on tape from reel to reel. Unfortunately, the quadraphonic sound, which delivered a discreet sound from four speakers placed in every corner of a room, was confusing and short-lived – not thanks to companies vying for formats (sounds familiar?).

Immersion in a three-dimensional audio sphere, however, should not be abandoned. In 1982, Dolby Laboratories introduced Dolby Surround, a technology that transports a surround sound signal to a stereo source through a process called matrix encoding. Since then, Dolby, DTS and others with different iterations have improved the state of home surround sound. With so many options, the technology remains confusing to many. From standard 5.1

to Dolby Atmos setups with multiple overhead speakers, turning your head is a lot. Our detailed guide aims to provide a bit of clarity to help you in your quest for surround sound.

Surround sound 101

The speakers

Surround sound, in its most basic form, includes a set of stereo front speakers (left and right) and a set of surround speakers, which are usually just at the sides and just behind a central listening position are placed. The next step is the addition of a center channel: a speaker between the left and right front speakers that is primarily responsible for displaying dialogues in movies. So there are five speakers involved. We'll add more speakers later (much more actually), but for now, we can use this simple five-speaker setup as a springboard to get into the different sizes.

Matrix

For the purposes of this discussion, "matrix" has nothing to do with the Keanu Reeves. In this case, matrix refers to the encoding of individual audio signals within a stereo source. This approach was the basis for early surround sound formats such as Dolby Surround and Dolby Pro Logic and was partly motivated by the limited space for discrete information on early audio-video media, such as the VHS tape.

Pro Logic [19659005] Using the matrix process, Dolby & # 39; s Pro Logic surround has been developed to encode separate signals within the left and right channels. Dolby was able to allow home audio devices to decode two additional sound channels from media such as VHS tapes, which supplied the center channel and surround speakers with audio. Due to the limited space, matrix surround signals came with some limitations. The surround channels in standard Pro Logic were not in stereo and had limited bandwidth. That means each speaker played the same and the sound didn't contain much bass or treble information.

5.1: Surround takes shape

Dolby Digital 5.1 / AC-3: The benchmark

Remember LaserDisc? Although the medium was first invented in 1978, it was not until 1983 when Pioneer Electronics acquired a majority stake in the technology that had some form of success in North America. One of the advantages of LaserDisc (LD) is that it offered much more storage space than VHS tape. Dolby took advantage of this and created AC-3, now better known as Dolby Digital. This format improved over Pro-Logic by allowing stereo surround speakers that could deliver higher bandwidth sound. It also facilitated the addition of a low-frequency effect channel, by adding the ".1" in 5.1, which is handled by a subwoofer. All information in Dolby Digital 5.1 is separate for each channel – matrix formation is not necessary.

With the release of Clear and Present Danger on LaserDisc, the first Dolby Digital surround sound entered the home theater. By the time DVDs came out in 1997, Dolby Digital had become the standard format for surround sound. To this day, Dolby Digital 5.1 is considered by many to be the standard for surround sound, which is still found on most Blu-ray discs.

  5-1 dolby setup Image courtesy of Dolby

DTS: The Rival

What is a technology market without a bit of competition? Dolby more or less dominated the surround sound landscape for years. Then, in 1993, DTS (Digital Theater Systems) came by, providing its own digital surround sound mixing services for film production, and visiting theaters for the first time with Jurassic Park . The technology eventually trickled down to LD and DVD, but was initially available on a very limited selection of discs. DTS uses a higher bit rate and therefore provides more audio information. Think of it as the difference between listening to an MP3 file at 256 kbps and 320 kbps. The quality difference is noticeable, but as with so many audio-related comparisons, not everyone is sold on it.

6.1: Taking it up a notch

In an attempt to improve the surround sound through the & # 39; soundstage & # 39; expand 6.1 has added another sound channel. The sixth speaker would be placed in the center of the back of a room and was later called a rear surround or rear surround. This was where a lot of confusion started to revolve around surround sound.

People were used to seeing (wrongly) surround speakers as "rears" because they were so often seen behind a sitting area. However, the recommended speaker placement has always resulted in surround speakers being placed on the sides and just behind the listening position.

The purpose of the sixth speaker is to give the listener the impression that something is approaching from the rear or disappearing to the rear. Calling the sixth speaker a "back surround" or "surround back" speaker, while technically accurate, was just confusing.

To make it even more confusing, each company offered different versions of 6.1 surround. Dolby Digital and THX have teamed up to create a version called "EX" or "Surround EX". It uses the proven matrix encoding method to embed the sixth channel in the surround left and right signals.

DTS, on the other hand, offered two separate 6.1 versions. DTS-ES Discrete and DTS-ES Matrix perform as their name suggests. ES Discrete programs specific sound information onto a DVD or Blu-ray disc, while DTS-ES Matrix uses the same technique as Dolby Digital EX to extrapolate information from the surround channels.

7.1: The Spawn of Blu-ray

  7-1 Dolby Setup

Just as people were getting used to 6.1, 7.1 came along with HD DVD and Blu-ray discs as the new indispensable surround format, which essentially replaced its predecessor. Like 6.1, there are several versions of 7.1, all of which add a second surround back speaker.

The surround effects that once went to just one surround back speaker could now go to two speakers in stereo. The information is discreet, which means that each speaker gets its own specific information – we can thank the enormous storage potential of Blu-ray for that.

Those who bought a dedicated back surround speaker now found themselves looking for a new matching pair of rear surrounds – typically the exact same model they'd bought for the left and right surrounds.

Dolby offers two different 7.1 surround versions. Dolby Digital Plus is the & # 39; lossy & # 39; version. Rather than using matrixing, lossy compression is applied to all individual audio channels, which helps take up less space on a Blu-ray disc. Dolby TrueHD, on the other hand, is lossless. Since no compression is involved, Dolby TrueHD is intended to be identical to the studio master.

DTS also has two 7.1 versions, which differ in the same way as Dolby & # 39; s versions. DTS-HD is a lossy, compressed 7.1 surround format, while DTS-Master HD is lossless and is intended to be identical to the studio master.

It is important to note that 7.1 channel surround mixes are not always recorded on Blu-ray discs. Movie studios should choose to mix before 7.1, and they don't always do. Other factors are also involved. Storage space is the most important among them. If a lot of extras are placed on a disc, there may not be room for the extra surround information. In many cases, a 5.1 mix can be expanded to 7.1 through a matrix process in an A / V receiver. This way those rear surround speakers get used to it, even if they don't get discrete information. However, this is becoming less and less common, especially when it comes to 4K Ultra HD Blu-ray discs, which often support multiple seven channel mixes.

9.1: Pro Logic is Coming Back

<img src = "data: image / gif; base64, R0lGODlhAQABAIAAAAAAAP /// yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-dt-lazy-src = "https://icdn2.digitalends /image/digitaltrends/svs-utra-tower-surround-family-720×720.jpg "onerror =" dti_load_error (this) "class =" size-large wp-image-434510 dt-lazy-load dt-lazy-pending "alt = "svs ultra tower surround family [19659026] If you are looking for a receiver, you may have noticed that many offer one or more different versions of Pro Logic processing. In the modern Pro Logic family we now have Pro Logic II, Pro Logic IIx and Pro Logic IIz Let's see what they all do.

Pro Logic II

Using the same matrixed four-channel sound as Pro Logic, Pro Logic II can create a 5.1 surround sound mix from a stereo source Pro Logic II also has another trick up its sleeve: it can separate the surround signal into stereo left and right channels instead of Pro Logic & # 39; s dual-mono presentation. This processing mode is often used when watching non-HD TV channels with a stereo-only audio mix.

Pro Logic IIx

If your video source is presented in 5.1 surround – and your home theater system supports additional speakers – Pro Logic IIx can take that mix and expand it to 6.1 or 7.1. Pro Logic IIx is divided into a movie, music and game mode.

Pro Logic IIz

Pro Logic IIz allows the addition of two "front height" speakers placed above and between the main stereo speakers. This form of matrix processing is intended to add more depth and space to a soundtrack by outputting sounds from an entirely new location in the room. Since IIz processing can be used with a 7.1 soundtrack, the resulting format could be called 9.1.

Despite the addition of these height channels, Pro Logic IIz does not allow true 3D sound placement. To make that possible you need Dolby Atmos or DTS: X, which we describe below.

What about 7.2, 9.2 or 11.2?

As we mentioned earlier, the ".1" in 5.1, 7.1, and all others refer to the LFE (low-frequency effects) channel in a surround soundtrack, which is handled by a subwoofer. Adding ".2" simply means that a receiver has two subwoofer outputs. Both connections provide the same information, since there is only one subwoofer track for Dolby and DTS. Since manufacturers of A / V receivers wanted to market the additional subwoofer output easily, the idea of ​​using ".2" was adopted.

For most people, the presence of a single subwoofer will provide enough bass and rumble. However, adding a second sub can enhance this effect, especially in larger media spaces. Check out our subwoofer installation guide to find out why a second subwoofer might be right for you.

Audyssey DSX and DSX 2

Audyssey, a company best known for its automatic calibration software found in many of today's A / V receivers, has its own surround solution called Audyssey DSX. DSX also allows for additional speakers that go beyond the core 5.1 and 7.1 surround formats, upgrading 5.1 and 7.1 signals to add more channels. With the addition of front and front channels at the top of a 7.1 system, Audyssey offers 11.1 channels of surround sound.

There is also Audyssey DSX 2, which adds up-mixing of stereo signals to surround sound. However, with the advent of object-based 3D formats such as Dolby Atmos and DTS: X in recent years, Audyssey has declined (see below).

3D / Object Based Surround Sound

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The latest and greatest development in surround sound is known as "object-based" or "3D" surround, for viewers' provides the best description of this technology for its ability to make sounds feel as if they are moving through space.You can hear a helicopter take off clearly in front of you, hover above your head and then disappear into the distance behind you.

"Object-based" is a better name for the sound professionals who create these 3D soundtracks, because it describes their ability to create a single sound-producing object (such as the heli kopter) anywhere in the 3D space.

This immersive hemisphere of sound is made possible by adding separate channels for ceiling or ceiling-mounted loudspeakers in A / V receivers at home.

Since these channels no longer need to extrapolate their signals from audio to other speakers, as they did with Pro Logic IIz 7.1, they get their own number. For example, a 5.1.2 system would have the traditional five channels and a subwoofer, but would also have two additional speakers that add height information in stereo to the front. A 5.1.4 system would add four additional height channels to 5.1, including two in the front, two in the back, and so on.

Dolby Atmos

Atmos in theaters

This should come as no surprise after reading the rest of this article, but Dolby is the current leader in object-based surround sound technology. In a theater with Dolby Atmos, up to 128 different sound objects can be reproduced in a given scene, which can be routed to 64 different speakers. If there had been an explosion on the right side of the screen in the past, half of the theater would hear the same sound. With Atmos, the sounds enter a theater from different locations based on where they are placed by professional audio mixers.

Atmos in the house

  Onkyo 7.2 channel 4K AV Dolby Atmos receiver

Atmos started to be available in A / V receivers in 2015, in a much more limited capacity than the professional format. As mentioned above, the most common configurations are 5.1.2 or 5.1.4, which add two and four height speakers respectively to a traditional 5.1 surround setup, although Dolby supports much larger configurations. Atmos took off relatively quickly and now most A / V receivers above the low range of the spectrum now support the format. In fact, every receiver on the list of our favorite A / V receivers supports Atmos, even models priced from $ 500 or less.

In 2015, Yamaha introduced the first Atmos-compatible soundbar, the YSP-5600, which fires up drivers to bounce sound off the ceiling. Since then, soundbar manufacturers have fully embraced Dolby Atmos. Some achieve the Atmos effect with dedicated wireless surround speakers with up-firing drivers to complement the front speakers in the bar. Others use a technique known as virtualized Dolby Atmos to convincingly simulate the Atmos effect with fewer speakers.

Some TVs, such as LG's line of exquisite OLED TVs, claim Dolby Atmos support through the TV's built-in speakers. Since Dolby Atmos can only be calibrated for two channels, we assume that this is technically accurate. Buyers should be aware, however, that two-channel Atmos will never sound as good as discrete 5.1.2 or better Atmos.

Movies with Dolby Atmos soundtracks are now common on Blu-ray and Ultra HD Blu-ray discs, and streaming sites like Netflix, Vudu, Amazon Prime Video, Disney + and Apple TV + all offer a selection of Atmos- movies and shows. Atmos is even starting to appear in some live broadcasts. Recent examples include the 2018 Winter Olympics, the NHRA's live drag racing events, and also music festivals.

One thing to keep in mind with Dolby Atmos: it is a picky beast. In order to hear Dolby Atmos sound, every part of your home theater system – from the source to the speakers – must support it. Here is our full guide to getting great Dolby Atmos sound.

Dolby Atmos Music

Although Dolby Labs is still in its early stages, it has partnered with major record labels and streaming services to develop the use of Dolby Atmos technology for music production. . The concept is simple: Dolby Atmos Music uses the same object-oriented 3D audio tools as the Dolby Atmos movie soundtrack version, but puts them in the hands of professional music producers.

The result is immersive music that goes far beyond what traditional two-channel stereo or even quadrophone sound can achieve. Unfortunately, Dolby Atmos Music is currently very limited. The only way to hear it with a Dolby Atmos equipped home theater is to buy one of the few Blu-ray discs that contain a Dolby Atmos Music mix, such as the recently remastered and re-released Kick from INXS.

Amazon Music HD recently became the first music streaming service to offer Dolby Atmos Music tracks, but the only way you can hear them is through Amazon's Echo Studio 3D smart speaker.

In a few select clubs, Dolby Atmos Music is used by DJs and other live performers to create an immersive music environment for dance floors.

Hopefully Dolby will open the locks on Dolby Atmos Music soon and find more ways for people to experience it.

It is worth noting that Sony also has an immersive 3D music format known as Sony 360 Reality Audio that competes with Dolby Atmos Music. It can also be found on some streaming services, but as with Atmos Music, the devices needed to hear it are limited to just a few options at the moment.

DTS: X

As with other surround sound types, DTS released its own version of object-based audio, DTS: X, in 2015. While Dolby Atmos limited objects to 128 per scene in theaters, DTS: X does not impose such limits (although whether movie mixers encounter themselves against the limitations of Atmos is questionable). DTS: X also aims to be more flexible and accessible than Atmos, leveraging pre-existing speaker layouts in theaters and support for up to 32 different speaker configurations in the home.

While DTS: X was previously addressed in updates for Atmos-compatible A / V receivers, it is now available with newer A / V receivers right out of the box. Companies like Lionsgate and Paramount offer home releases in DTS: X, but the lack of widespread adoption on disk-based media – and no adoption among streaming services – is the biggest limiting factor, as almost all A / V receivers now support it. [19659006] DTS Virtual: X

DTS also recognizes that not all movie buffs have the space or time to assemble an object-based sound system. Research collected by DTS found that less than 30 percent of customers actually connect height speakers to their systems, and less than 48 percent even connect surround speakers.

To that end, the company developed DTS Virtual: X, which uses Digital Signal Processing (DSP) with the aim of providing the same spatial cues that a traditional DTS: X system could provide, but with a smaller number of speakers, even if you only have two. This technology was first rolled out in sound bars, which makes sense because they often only include a separate subwoofer and at most a few satellite speakers. Since then, companies like Denon and Marantz have added support for DTS Virtual: X to their receivers, while Sony has its own virtual surround soundbar that reads DTS: X and Atmos mixes.

Technically speaking, "virtualized" Dolby Atmos and DTS Virtual: X are very similar, but Dolby prefers not to distinguish between Dolby Atmos implementations. As for Dolby, Atmos is Atmos, whether virtualized through two, three or five channels, or fully baked with a discreet 5.1.2 or better speaker system.

Auro-3D

It may not be known as Atmos or DTS: X, but Auro-3D has been around much longer than either. The technology was first announced in 2006 and has been used in theaters ever since, although it has only recently come on the market for home theater systems with companies like Marantz and Denon offering it as a firmware upgrade – usually a paid upgrade.

While similar to Dolby Atmos in some ways, Auro-3D uses three & # 39; sound layers & # 39; to achieve the immersive effect. Those layers typically require more speakers – up to 11 in an ideal setup – making Auro-3D more expensive to implement at home. Since Auro-3D usually uses a single overhead channel, the speaker configurations are not optimal when used with Dolby Atmos sound.

So far, Auro-3D has not been widely used in American homes, although the company claims to enjoy considerable popularity in Europe and Japan.

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