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Dolby Surround Systems - from the beginning to Dolby Atmos

From mono to Dolby Surround 5.1 and 7.1 up to the three-dimensional sound of home theater systems

When it comes to images, 3D is on everyone's lips and the manufacturers are trying to bring the image of TVs and projectors closer and closer to reality with ever more refined technology in order to draw us into the film scene. But what is sold as the latest craze in the picture is old hat when it comes to sound ...

In fact, we perceive our world not only visually in three dimensions with two eyes, but also acoustically with our ears. In "real time" the auditory cortex of our cerebrum detects minimal differences in the transit time of noises and thus calculates the angle of incidence of the sound source. For example, a sound coming from the left reaches the left ear earlier than the right ear. The brain “measures” the time lag and immediately knows how far to the left the sound is coming from. The system works so precisely that we can perceive the background noise around us in all directions, in 360 °, so to speak.

The problem of forcing a three-dimensional sound into a closed (cinema) room is evident: If all loudspeakers are only in front of us (ears), it is almost impossible to generate sound from all sides. In order to simulate certain sound directions or surround sound for our ears, we therefore need several loudspeakers that are coordinated with one another. The sound of the film must serve them all individually, multi-channel sound is necessary.

The potential of three-dimensional soundscape Filmmakers have long been aware of the fact that the first multi-channel systems existed in selected cinemas as early as the 1940s and the sound formats on 70mm film strips basically also allowed the use of an effects channel, but it was not until the 1970s that the sound specialist Dolby Multi-channel systems technically simplified and so brought into most public cinemas. And it took another 10 years for multi-channel sound to find its way into the four walls of your home, also through Dolby Laboratories:


First generation: Dolby Surround


First generation: Dolby Surround


Home cinema in the classic sense only became possible with the ability to record feature films. The good old VHS cassette, despite its poor quality, was the first mass recording medium that made it possible to buy films for home use. The laser disc soon followed, which, due to the optical scanning (like a CD), was far superior in terms of image and sound, but was not suitable for recording.


Laserdisc & VHS: Pioneers in home theater consumer media


Both systems only support hi-fi stereo sound, from multi-channel in the truest sense of the word "no trace". The way to multi-channel sound for the home seemed blocked. But then came Dolby came up with the idea of ​​modulating an additional surround channel into the stereo signal, killing two birds with one stone. The system was fully stereo downward compatible and was retained in full during subsequent transfers. All it took was a Dolby Surround decoder that was looped into the analog audio chain and filtered the surround channel out of the stereo channel and distributed it to two additional loudspeakers in the back of the room.


First generation: Dolby Surround


With the help of the additional surround speakers, it was possible to better distribute the soundscape in the room and also to create effects from behind or from the side. The audience felt better in the action, the atmosphere of the soundtrack increased.

But this modulation technique also had serious weaknesses. Despite two loudspeakers that was Surround channel only mono, a separation between right / left behind was not possible. In addition, the frequency range was severely limited, and deep tones, as needed for room-filling explosions, were not possible. The use of the first surround sound was correspondingly subtle.


Second generation: Dolbby Surround Prologic

Second generation: Dolby Surround Prologic


The lack of the center between the two front speakers was even more serious than the original in the cinema. Conventional stereo is able to reproduce the center acoustically, but only if the listener is exactly on the center axis between the loudspeakers. The dialogues in a film should always come from the direction of the actors, even if you are not sitting optimally on the edge of the room. This becomes even more important when the front speakers are far apart.


Second generation: Dolby Surround Prologic


Dolby succeeded with the "ProLogic" system to modulate another channel into the stereo signal, which represents the missing "center" between the front speakers. From now on you had a front threefold differentiated sound image supported by an atmospheric room (surround) channel. The frequency restrictions due to the modulation still remained.


Digital revolution: Dolby Digital


Digital revolution: Dolby Digital


Dolby Digital 5.1


From now on, the surround back sound was also stereo and no longer restricted. There is also a special one Low frequency channel for particularly low tones via the subwoofer. Five main channels plus one LFE channel added up to “5.1 Dolby Surround Digital ".


Dolby Surround 5.1


With the help of Dolby Digital 5.1 it is possible to create a very differentiated sound image, in which the events in front of and behind the viewer, as well as distributed throughout the room, can take place. The justifiable balance between the number of loudspeakers and the sound result has ensured that the 5.1 system has established itself as the standard for home cinema to this day.


Dolby Digital 5.1 vs. 7.1

Dolby Surround 7.1

With new media like Blu-Ray there is no longer any limited storage space for the sound, which is why the number of channels increased over time to 7.1 (seven main channels). The main reason for this expansion is the precision of our ears: The stereo division of the surround channel in 5.1 allows for an atmospheric soundscape and the division between left and right, but the differentiation “next to the viewer” and “behind the viewer” still leaves to be desired.

The 7.1 system solves this problem, because it divides the surround areas into side and rear with two additional channels, also in stereo in each case. Thus, for the first time, the 360 ​​° circle around the viewer is closed: front left, middle, front right, right, back right, back left, left!


Dolby Surround 7.1


Undoubtedly superior to the 5.1 system in terms of quality (because a 7.1 system can completely simulate a 5.1 system if necessary), was Dolby Digital 7.1 has not yet been suitable for the masses, probably due to the large number of speakers that have to be distributed in the room and the fact that a new decoder is required and still not all movies are on Blu-Ray provide native 7.1 sound as a recording (although the number is steadily increasing).


What Dolby Surround system suits you?

Which system you choose depends on the

  • spatial possibilities,
  • the personal demand for perfection
  • and the willingness to invest.

At this point we show three of the many example systems that we have available for you in our specialist shops:

The Monitor Audio MASS system proves that 5.1 surround sound does not have to be expensive. With its low price, it not only offers six discreet sound channels, but thanks to the compact design of the chassis it also enables inconspicuously elegant installation in the living room (optionally in white or black). Correctly set up, the subwoofer takes over the non-locatable deep bass range in the center without provoking a roar.

With a price starting at € 1900 for a complete 5.1 set, the “Monitor Audio Radius” series, with its numerous components, offers optimal configuration options for high demands in the timelessly elegant Bauhaus style.

Monitor Audio Radius 5.1

If you want it inconspicuous, choose the Radius 90 with its particularly compact dimensions, for the full frequency response we recommend the Radius 270. The center loudspeakers Radius 200 or 225 are optimally tuned in terms of sound 380 subwoofer, or for larger rooms with the stronger brother Radius 390.

Finally, the Monitor Audio bronze, silver or gold series are recommended for the uncompromising sound volume in 7.1 digital multi-channel sound.

Monitor Audio Silver 7.1

The large volume and the complete frequency response mapped floor-standing loudspeakers ensure an authentic cinema production that does not go to its knees even at higher levels. For the surround channels, you can choose between conventional direct radiators and dipole speakers (FX).

Monitor Audio Silver Dipole Loudspeaker

Dipole or direct, which system is more suitable, depends on the spatial conditions. If the cinema room offers enough space on all sides (over 1.5m) and if the seated position of the audience is in the room (and not on the back wall), direct emitters can be used. But the smaller the room, the greater the risk that one of the speakers will sound disproportionately loud in the ear of the viewer (who is not sitting in the perfect place) and thus destroy the balance and thus the soundscape. For a more diffuse sound it is better to use dipole loudspeakers, as they radiate out of phase in all directions and thus produce a wider, less intrusive sound. The localization precision of effects suffers as a result, so that it is generally advisable to determine personal preference in a hearing test. In all home cinema room branches there are of course 5.1 / 7.1 dipole and direct systems available for a sound comparison, including individual, competent advice from our trained staff.



The next evolutionary stage: Dolby Atmos


The evolutionary stage: Dolby Atmos

Even if seven loudspeakers + subwoofers seem like a lot, in terms of sound precision they are still not the end of the line, because our ears are too precise to be exhausted. For years, manufacturers have therefore not put an end to eight channels, but have brought amplifier systems with up to 11.2 channels onto the market. In the absence of software support, such 11.2 receivers are dependent on sound processors that interpolate the other four channels from the conventional surround track.

The native 13-channel sound for the home has been a utopia so far, but home cinema fans seem to benefit from the “big cinemas” again. Because time didn't stand still there either, and Dolby has a new sound experience with “Dolby Atmos ”, which is currently establishing itself in the high-end cinema world.


Dolby Atmos


The sound from above

Indeed, Dolby does Atmos But no more with the fixed channel system, in which each loudspeaker has a dedicated tone. Instead, the sound effects are now positioned by the sound engineers in a kind of virtual coordinate system and the intelligent Dolby Atmos The processor accordingly calculates the individual sound channels depending on the individual cinema room conditions, the properties of which were programmed in advance on site. This ensures an optimal and unprecedented sound positioning. So the rain really laps down from above and when the planes appear in the sky at Pearl Harbor, you will instinctively bow your head. A trip into space like Star Wars or Gravity becomes a new experience. Instead of just being there, you are now really in the thick of it!


Dolby Atmos processor


In addition to a new decoder, the loudspeaker matrix required in the cinema is enormous: no less than 64 loudspeakers create the sound space (see sketch). The 18 ceiling speakers, which also enable the sound to be positioned in the room, directly above the audience, are of particular importance.


Dolby Atmos in the cinema

Until recently, the Dolby stayed Atmos System reserved exclusively for large public cinemas, implementation for the home seemed too utopian and impractical. Fortunately, Dolby remains Here, too, true to its line and has developed a home cinema version in parallel. The focus was on compatibility with current high-end amplifier / speaker systems.

But of course it won't work without rearranging the surround set. As already explained, previous 7.1 to 11.2 systems already completely cover the 360 ​​° rotation around the viewer, but the "Y-axis", i.e. the level above the listening position, has been neglected so far.

This gap appears with the Dolby Atmos System for home now through special ceiling speakers closed. Various configurations are possible to ensure compatibility as an expansion set with previous systems. The ceiling extension is indicated by a third number in the scheme "x.x.x":


Dolby Atmos 5.1.2


If you have an 8-channel (7.1) amplifier, you can add two additional ceiling speakers, a Dolby Atmos Set up the "5.1.2" system. The previous 5.1 loudspeaker constellation is retained.


Dolby Atmos 5.1.4


In connection with a 9.1 amplifier, the ceiling array can be expanded with four ceiling speakers (5.1.4), which allows a more precise sound position in the room.


Dolby Atmos 7.1.2


Alternatively, with the same number of channels (9.1), a 7.1.2 system can be set up if a full 7.1 system is already available.


Dolby Atmos 7.1.4


The ideal solution is undoubtedly the full equipment of the home cinema with four surround speakers and four ceiling speakers. In total, these are 11.1 speaker channels that have been supported by high-end amplifier / power amplifier combinations for years.

“Even more loudspeakers?!?!” Some readers will now say, shaking their heads, that even among high-enders this is not practicable for everyone. But one has also thought of that:


"Virtual Atmos System"


If you don't want to mount four additional speakers on the ceiling, you can also use Atmos-compatible dipole speakers. These have a ceiling-facing chassis and generate the upper channels by reflecting the ceiling. This means that the familiar 5.1 setup is retained and the integrated Atmos compatibility is optically invisible.

There remains the question of the software and the necessary decoder. Fortunately, this is easy because current AV receivers support Dolby ATMOS.

Yamaha AV Receiver


Talk to us about this in our specialist shops. We will give you the various techniques in the form of

  • 2.1 Home theater systems
  • 5.1 Home theater systems
  • 7.1 Home theater systems
  • and Dolby Atmos in practical home cinema versions

Present living worlds and home cinemas in detail and optimized for your needs in our HOME CINEMA ROOM. Visit us in your area.


And the film studios also seem to be getting a taste for it: the first feature films should be on Blu-Ray this year with native Dolby -Atmos sound appear in time for Christmas sales. The highlight: an update of the Blu-Ray Player is not necessary, every commercially available player will have PCM can output the soundtrack.




There is no doubt: a true cinema feeling is not only created by the large projector image, the sound is just as important. Only when our field of vision is filled and the sound is distributed around us in the room are we part of the action and captivated with almost all of our senses (good film required).

Those who want to do justice to the precision of our hearing cannot avoid a perfectly installed multi-channel surround system. And be it conventional AC3 5.1, Dolby Digital 7.1 or even Dolby s latest high-end process Atmos up to 7.2.4, a tailor-made solution is possible for every room, every approach and every budget, which guarantees many years of film fun.

So don't be afraid to take a seat in one of the many HOMEKINORAUM specialty stores throughout Germany and hear a direct comparison of all systems. We guarantee in advance: You will be delighted and find the optimal constellation for you together with us! We are looking forward to your visit.

Find the nearest HOMEKINORAUM specialty store in your area or browse directly for the right Dolby Surround systems in our online shop.