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The Ultimate Surround Sound Guide: Explaining Different Formats



It was summer 69. We are not talking about the Bryan Adams song here; We actually refer to the first time that surround sound became available in the home. It was called Quadraphonic Sound, and it first came home to audio buffs through reel-to-reel tape. Unfortunately, Quadraphonic was only very short-lived. The technology that provided discreet sound from four speakers placed in each corner of a room was confusing – no, thanks to electronics companies arguing over formats (sounds familiar?) – and it did not succeed.

Immersion in Three The three-dimensional sphere of audio bliss, however, should not be abandoned. In 1982, Dolby Laboratories introduced Dolby Surround, a technology in which a surround sound signal was transmitted to a stereo source through a process called matrix coding. Not long after, Dolby Pro Logic Surround has brought us and has been helping to improve the state of home surround sound for an increasing number of channels and configurations ever since.

Surround sound has become a standard recording in home theaters, but for many it remains a confusing technology. Although most understand the concept of using multiple speakers for theater-like sound, many do not understand the difference between all formats. From simple 5.1

to Dolby Atmos setups with multiple overhead speakers, it's a lot to wrap around your head. We hope to give you some clarity with our detailed guide to help you with your surround sound search.

Surround Sound 101

The Speakers

surround sound is basically a stereo front speaker (left and right) and a set of surround speakers, usually just on the sides and directly are placed behind a central listening position. In the next step, a center channel is added: A speaker between the front left and right speakers, which is mainly responsible for playing back dialogs in movies. That's why we have five speakers. We'll be adding more speakers later (actually much more), but for the moment we can use this simple five-speaker arrangement as a stepping stone to get into the different formats.

Matrix

For this purpose discussion, "Matrix" has nothing to do with the legendary Keanu Reeves films. In this case, the matrix refers to the encoding of separate 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 partially motivated by the limited space for discrete information on early audio-video media such as the VHS cassette.

Pro Logic

19659006] Using the Matrix process, Dolby Pro Logic Surround has been developed to encode separate signals within the left and right main channels. Dolby was able to decrypt two audio channels from home media devices, such as VHS tapes, which powered the center channel and surround speakers with audio. Due to the limited space, there were some limitations with matrixed surround signals. The surround channels in Basic Pro Logic were not stereo and had limited bandwidth. This means that each speaker played the same and the sound did not contain much bass or treble information.

5.1: Surround takes shape

Dolby Digital 5.1 / AC-3: The Scale

Remember LaserDisc? Although the medium was only invented in 1978, it was not until 1983, when Pioneer Electronics bought a majority stake in the technology, that it had any sort of success in North America. One of the advantages of LaserDisc (LD) is that it provides much more storage space than VHS tape. Dolby took advantage of this and created AC-3, better known as Dolby Digital. This format improved with Pro-Logic in that it enabled stereo surround speakers that could provide higher bandwidth sound. It also facilitated the addition of a low-frequency effects channel by adding in 5.1 the ".1" handled by a subwoofer. All information in Dolby Digital 5.1 is discrete for each channel – no matrixing required

With the release of Clear and Present Danger on LaserDisc, the first Dolby Digital surround sound has hit theaters. Even when DVDs came out in 1997, Dolby Digital was the standard surround format. To date, Dolby Digital 5.1 is considered by many to be the surround sound standard still found on most Blu-ray Discs.

  5-1-dolby-setup Courtesy of Dolby

DTS: The Rival

What is a technology market without a little competition? Dolby has mastered the surround sound landscape for years more or less. In 1993, DTS (Digital Theater Systems) was added, offering its own digital surround sound mixing services for film production, first released in Jurassic Park . The technology was eventually transferred to LD and DVD, but was initially available only for a very limited selection of discs. DTS uses a higher bitrate and therefore provides more audio information. Think of it as the difference between listening to a 256kbps and 320kbps mp3 file. The difference in quality is noticeable, but in some cases negligible

6.1: One Level Up

To improve the surround sound by extending the "Soundstage", 6.1 added another sound channel. The sixth loudspeaker should be placed in the middle of the back of a room and was referred to as the rear bezel or rear bezel. This is where a lot of confusion whirled around surround sound. People were accustomed to calling surround speakers (falsely) "rear" because they were so often placed behind a sitting area. However, the recommended placement of the speakers always requires the placement of surround speakers on the sides and just behind the listening position.

The sixth loudspeaker should give the listener the impression that something is approaching from behind or disappearing. Designating the sixth speaker as a "back surround" or "surround back" speaker was, technically, an accurate description, simply confusing.

To make things even more confusing, each company offered different versions of 6.1 Surround. Dolby Digital and THX worked together to create a version called "EX" or "Surround EX," in which the information for the speaker in the left and right surround speakers is matrix-encoded. DTS, on the other hand, offered two separate 6.1 versions. DTS-ES Discrete and DTS-ES Matrix performed their names. ES Discrete programmed specific sound information onto a DVD or Blu-ray Disc, while DTS-ES Matrix extrapolated the information from the surround channels.

7.1: The Spawn of Blu-ray

Just when people started to come to 6.1, 7.1 came in conjunction with HD DVD and Blu-ray discs as the new must-have surround format, in the Essentially replacing its predecessor. Like 6.1, there are several different versions of 7.1, all of which are added in a second back-surround speaker. The surround effects, once reserved for a surround back speaker, could now go to two speakers in stereo. The information is discrete, which means that each speaker receives their own specific information – we can thank the huge storage potential of Blu-ray for that.

Dolby offers two different 7.1 surround versions. Dolby Digital Plus is the "lossy" version, which still compresses data and requires less space on a Blu-ray Disc. Dolby TrueHD, on the other hand, is lossless. Since Dolby TrueHD should not be compressed, Dolby TrueHD should be the same as the Studio master.

  7-1-dolby-setup Courtesy of Dolby

DTS also has two 7.1 versions that differ in the same way as Dolby's versions. DTS-HD is a lossy, compressed 7.1 surround format, while DTS-Master HD is lossless and should be the same as the Studio master.

It is important to note that 7.1-channel surround mixes are not always included on Blu-ray. Rays discs. Film studios must choose to mix 7.1 and do not always do so. There are other factors. Storage space is the most important among them. If a number 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 by a matrix process in an A / V receiver. This will use the surround back speakers even if they do not receive discrete information. However, this is becoming increasingly rare, especially for 4K Ultra HD Blu-ray discs, which often support multiple seven-channel mixes.

9.1: Pro Logic makes a comeback

If you're already shopping 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 take a quick look at what each of them is doing.

Pro Logic II

Pro Logic II is similar to its early Pro Logic predecessor in that it can make 5.1 surround sound from a stereo source. The difference is that Pro Logic II provides stereo surround information. This processing mode is often used when watching non-HD TV channels with a pure stereo mix.

Pro Logic IIx

Pro Logic IIx is one of the above processing modes that can capture and expand a 5.1 surround mix into 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 editing aims to give a soundtrack more depth and space by outputting sounds from a whole new place in the room. Since IIz processing can be accomplished with a 7.1 soundtrack, the resulting format might be named 9.1

What about 7.2, 9.2, or 11.2?

As mentioned previously, the ".1" in 5.1, 7.1 and all the others refer to the LFE (Low Frequency Effects) channel in a surround soundtrack handled by a subwoofer. Adding ".2" simply means that a receiver has two subwoofer outputs. Both connections provide the same information as there is only one subwoofer track for Dolby and DTS. Since A / V receiver manufacturers want to easily market the additional subwoofer output, the idea of ​​using ".2" was adopted.

Audyssey DSX and DSX 2

Audyssey, a company well-known for its auto-calibration software in many of today's A / V receivers, has its own surround solution called the Audyssey DSX. DSX also provides additional speakers that go beyond the Core 5.1 and 7.1 surround formats and upgrade 5.1 and 7.1 signals to add more channels. With additional front and front-height channels on a 7.1 system, Audyssey 11.1 provides surround sound channels. There is also Audyssey DSX 2, which adds stereo signals to surround sound. However, with the advent of object-based formats such as Dolby Atmos and DTS: X, Audyssey has seen a decline in recent years (19659004) 3D / object-based surround sound

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The latest and greatest development in surround sound is not just discrete audio for treble channels, but also a new way for sound engineers to mix audio for the most accurate, hemispheric immersion.The name "object-based" is used because the on-film audio mixers with this discrete third dimension are individual sound objects – such as a buzzing sound Bee or one Helicopters – can represent in 3D space and are not constrained by a standard channel setup

Adding discrete channels for ceiling or ceiling speakers in A / V receivers at home, height channels are now represented as separate separate units, resulting in one additional number used to represent surround channels in residential buildings. 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 stereo height information at the front. A 5.1.4 system would add to 5.1 four additional treble channels, including two on the front, two on the back, etc.

Dolby Atmos

Atmos in Theaters

This should not come as a surprise after reading the rest of this article, but Dolby is the current leader in object-based surround sound technology. In a theater equipped with Dolby Atmos, up to 128 different sound objects can be displayed in a given scene (compared to, for example, seven full channels for Dolby Digital 7.1), which can be routed to 64 different speakers. If in the past there was an explosion on the right side of the screen, half of the cinema would hear the same sound. Atmos sounds will come from different locations in a theater, depending on where they are placed by professional audio mixers.

Atmos in the House

Atmos began in 2015 to be available in A / V receivers with 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 or four height speakers to a traditional 5.1 surround setup, although Dolby supports much larger configurations. Atmos started relatively fast as most A / V receivers over the lower part of the spectrum now support the format. In fact, every receiver on the list of our favorite A / V receivers supports Atmos, even models for $ 500 or less.

In 2015, Yamaha introduced the first Atmos-capable soundbar, the YSP-5600, the firing driver, to bounce sound from the ceiling. Others soon followed, including our hitherto most popular Samsung HK-950, which uses a total of four up-driving drivers and wireless surround speakers for a 5.1.4 Atmos configuration. There are even TVs like the LG W8 that directly support Dolby Atmos via an integrated soundbar. There are other agile speaker solutions that require a receiver, such as the miniaturized Sib Evo system from Focal.

The list of films using Atmos continues to grow and is offered through Blu-ray Discs and streaming sites such as Netflix and Vudu. The number of titles was initially small, but increased steadily with each additional week. Atmos even appears in some live broadcasts, including the 2018 Winter Olympics.

DTS: X

Just like other types of surround sound, DTS has its own version of object-based audio, DTS: X, unveiled in the year 2015. While Dolby Atmos limits objects to 128 per scene in theaters, DTS: X does not have such limits (though it is questionable whether movie mixers bump into the limits of Atmos). DTS: X also aims to be more flexible and accessible than Atmos, leveraging existing speaker layouts in theaters and supporting up to 32 different speaker configurations in the home.

While DTS: X was previously available in updates for Atmos-enabled A / V receivers with newer A / V receivers now. Companies like Lionsgate and Paramount offer home releases in DTS: X, but are less popular than Atmos for the time being. Still, this is a relative matter: any recipient on the above list of our preferred A / V receivers supporting Atmos will also support DTS: X, and you'll find that this is consistently consistent.

DTS Virtual: X [19659006] DTS also recognizes that not all movie lovers have the space or time to put together an object-based sound system. DTS research revealed that fewer than 30 percent of customers actually connect height speakers to their systems, and less than 48 percent even surround speakers.

To this end, the company developed DTS Virtual: X, which uses Digital Signal Processing (DSP) with the aim to deliver the same spatial signals that a conventional DTS: X system could offer, but over a smaller number of Speakers, even if you only have two. This technology was first introduced into soundbars, which makes sense, as they often include only a separate subwoofer and perhaps a maximum of two satellite speakers. Since then, companies like Denon and Marantz have expanded their receivers with DTS Virtual X, while Sony has its own virtual surround sound bar that reads DTS: X and Atmos mixes.

Auro-3D

Maybe not as well 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 since been used in cinemas, although it has only recently been released on home theater systems with companies such as Marantz and Denon as a firmware upgrade – usually a paid upgrade.

Auro 3D does not use the term "object-based" like its competitors, but it works similarly with similar results, which increases the overall constraint on viewing a movie. The recent push of Auro-3D into the living room will probably not break the Dolby 3D surround crown, but considering that it's been 12 years, it's likely to stay there.






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