At the show, Craig Eggers, director of home theater at Dolby Laboratories, announced the official launch of the home version of Dolby Atmos surround sound technology, noting that this new technology solves the problem that previous home surround sound technology could not create a realistic upper sound field. In particular, through a unique new generation of speaker technology that supports Dolby Atmos, users can experience the power of panoramic sound technology without having to set up speakers in the ceiling. At the same time, Dolby officially put the Dolby Atmos technology and installation guide white paper on the official website of the English version, we finally have a more detailed understanding of the details of Dolby Atmos technology. In this issue, we will comprehensively analyze every detail of the home Dolby Atmos technology from technology to products. From the technical characteristics, installation rules, related AV amplifiers and speaker products, we will bring you a practical home Dolby panorama. Sound construction strategy. Welcome everyone to visit the home theater network shopping guide network! 
Dolby originally applied Dolby Atmos technology to professional cinemas. In major cities in China, more and more Dolby Atmos cinemas are constantly appearing, allowing audio-visual enthusiasts to experience the charm of this revolutionary surround sound technology.
The first film with the Dolby Atmos soundtrack, Brave, launched the prelude to panoramic sound in 2012 as a sound processing technology that revolutionized the surround sound of professional cinemas. Dobly Atmos is a breakthrough in surround sound technology. Now officially into the home theater, we can build a new surround sound system by supporting Dolby Atmos' AV amplifiers and speaker systems, or upgrade to support Dolby Atmos with existing systems. At the same time, it is precisely because Dolby Atmos is different from the characteristics of the previous surround sound technology, so that content creators can more accurately express various sound scenes and sports sounds in the home audio-visual space, which restores the excellent sense of presence and Sense of envelopment.
Compared to other different surround sound technologies, Dolby Atmos revolutionizes the replacement of channel-based surround sound systems. Dolby was the first to introduce channel-based surround sound technology, which brought 4-channel Dolby Pro Logic surround sound technology in the 1980s, and then led home surround sound technology from 5.1 to 7.1. . But when it comes to 9.1 or even 11.1 channels, the problems with this channel-based surround sound processing technology become more and more obvious. The key to the problem comes from the content, because most of the home theater surround sound audio content is processed by the content mixing of the cinema. The best case is only 7.1 channels, in most cases 5.1 sounds. Road. This means that if you want to achieve 9.1 or 11.1 channels, you have to decompose and recombine the original surround audio content, but the effect is often not as good. The main limiting factor is based on the channel. In our real life, the movement of sound is unique and complex. For example, the sound of a bird flying from a branch changes, the sound of fireworks rising and exploding at different sky heights and positions. and many more. For the channel surround sound system, simply changing the sound changes of the bird's flight from the upper left channel to the right front channel output does not accurately reflect the flight path of the bird when it falls. In the process of falling, the birds may have made different directions of conversion, but the channel-based surround sound system did not accurately describe the details of the sound, which caused the listener to lose a lot of sound details, making us The brain will inevitably doubt whether the image seen is true. In order to solve this problem, Dolby has invested a lot of research in reforming the current channel-based surround sound system in cinemas to relieve the creative limitations of film creators due to the channels, especially in the three-dimensional space. Real sounds, such as realistically presenting the sound details of the various complex changes in the bird's flight. Dolby's dispatch lab staff and Dolby technical engineers hand in hand to help the movie mixing studio create a Dolby Atmos soundtrack based on Sound object. In June 2012, the first film "Brave" with the Dolby Atmos soundtrack was born. Over the next two years, more than 150 Dolby Atmos movies were released.
Entered the family by a professional cinema
Dolby Atmos's uniqueness
Dolby Atmos finally entered the home theater from a professional cinema, although there are still big differences, but basically the concept of sound objects. Filmmakers and mixers can edit every sound object in the entire 3D sound scene with Dolby's unique content creation software. The minimum configuration of the Dolby Atmos system includes 5 ground speakers plus 2 upper sound field speakers. The picture on the right shows the maximum configuration of 24 ground speakers plus 10 upper sound field speakers.
What makes Dolby Atmos unique is that it introduces the concept of a sound object. It should be noted that it does not completely abandon the channel, but the introduction of sound objects on the channel makes the surround sound more realistic and enveloping. Among professional cinemas, Dolby Atmos is a highly enclosed sound scene consisting of 9.1-channel Bed audio based audio plus up to 118 simultaneous sound objects. The specific location and movement of the various sounds in this scene can be more realistically interpreted. Filmmakers and mixers can edit each sound object in detail through Dolby's unique content creation software, including the entire 3D sound scene. In the final mix, these sound objects will also be metadata metadata to express the characteristics of the sound object, including its position and movement information. This is the unique manufacturing method of Dolby Atmos, which has greatly changed the production of previous movie soundtracks.
Now that Dolby Atmos is officially in the home theater, we have been able to create a complete home theater surround sound system that supports Dolby Atmos. Home Dolby Atmos movies, whether Blu-ray discs or digital streaming media, each sound of a movie is a sound object during the mixing process. This means that the content of these movies does not have a specific channel setting, and it will not tell you whether the audio section is 5.1 or 7.1 as in the previous Blu-ray disc. This sound object-based audio signal will optimize the surround sound effect based on the number and placement of the speakers you use, including five speakers placed on the ground and two speakers that provide overhead sound. The 5.1.2 system consisting of 24.1.10 systems consisting of 24 ground speakers and 10 overhead speakers, pay attention to the middle .1 represents the subwoofer in the system. If you're playing a traditional channel-based 5.1 or 7.1 audio track, you can also extend it to a Dolby Atmos-compatible surround sound system with Dolby Atmos' surround sound processor.
Currently, Dolby Atmos is compatible with the audio formats in Dolby TrueHD and Dolby DigitalPlus. For example, in the Dolby TrueHD lossless audio compression format, a fourth substream is added for lossless adoption. The encoded signal of a complete sound object mix. In other words, you'll soon find a Blu-ray disc with Dolby Atmos audio with Dolby TrueHD HD lossless compression, or a Dolby Atmos broadcast TV audio signal with Dolby DigitalPlus HD compression. Both existing Blu-ray players and HD set-top boxes can play Dolby Atmos movies. There is no need to upgrade the Dolby Atmos audio signal to the corresponding Dolby Atmos home theater amplifier for decoding. If the amplifier does not support Dolby Atmos decoding, it does not matter, it will be output with the traditional 5.1 or 7.1 audio signal. In addition, the transmission of Dolby Atmos signals does not require the replacement of higher-level HDMI cables, and the existing HDMI high-speed wires can be fully supported.
Not complicated, but there are many places worth noting
Dolby Atmos home theater system basic construction strategy
The four conditions that must be met to build a Dolby Atmos system
â— A source device capable of playing Dolby Atmos audio content. Most existing Blu-ray playback devices and HD set-top boxes are competent
â—A Dolby Atmos compatible AV amplifier or preamp
â—Requires a speaker that reproduces the sound field above the head
â— The speaker must be able to withstand the need for long-term loud sound film playback. Most of the existing home theater speaker systems can be used to build Dolby Atmos systems.
Dolby Atmos signal source considerations
Must have source code output Most Blu-ray players in the mainstream can output DolbyAtmos audio tracks, but pay attention to HDMI output should select source output, turn off SecondaryAudio output function
The source system is the most critical factor for the entire Dolby Atmos system. On the one hand, we can choose a Blu-ray player that can play Dolby Atmos encoded content. On the other hand, we can also choose to support the output of Dolby Atmos content to source code. A gaming device, a Blu-ray player, or an HD streaming device among AV amplifiers. Supporting the output of the Dolby Atmos source code via the HDMI port is key. In addition, you need to turn off the SecondaryAudio output function in the Blu-ray player settings.
For Dolby Atmos decoding relies entirely on AV amplifiers
The core part of the entire system
AV amplifier or preamplifier plays a key role in Dolby Atmos audio decoding and processing. At this stage, Dolby Atmos audio decoding and processing relies entirely on AV amplifiers or preamps. Most Japanese and a few European and American brands are Models that support Dolby Atmos decoding have been introduced, and some brands support the upgrade of Dolby Atmos with software upgrades from earlier models. If you want to know if your AV amplifier can support Dolby Atmos, the easiest way is to see if the HDMI output terminal of the amplifier reaches 1.4 or above. If you do, you will support the Dolby Atmos software upgrade.
In addition, you need to be aware that the AV amplifiers that support Dolby Atmos have a speaker output terminal with a Height (upper channel). In the Dolby Atmos system, the speaker output terminal is used to connect the speaker above the head or Dolby. Atmos compatible upper sound field speaker. If you want to use four speakers in the upper sound field, you must pay attention to whether there are 4 speaker output terminals on the back of the amplifier.
However, after adopting the AV amplifier compatible with Dolby Atmos, most of the models need to be set in the user menu to select the type or specific position of the upper sound field speaker through the amplifier, and some amplifiers can automatically detect through the microphone. set up. This step is very important to ensure that Dolby Atmos's unique sound objects are rendered accurately. In addition, the equipment of the low frequency manager should also be set correctly to ensure that the ideal low frequency effect is reproduced in the system, especially the setting of the low frequency extension of the upper sound field.
The sound field experience above is the key to the three-dimensional sense of Dolby Atmos
Unusual three-dimensional sense of space from the upper sound field in the Dolby Atmos system
5.1 or 7.1-channel surround sound box system setup for ITU-R BS.775-3
Dolby Atmos can give you an unusual sense of three-dimensional space, the most important source is the upper sound field. To reproduce the sound field above, Dolby brings a new way of thinking for home theater design. For Dolby Atmos's home theater system, you can have a variety of different speaker options, and you don't have to completely replace the home theater speaker system you are currently using. Most home theater speaker systems are designed with one subwoofer with 5 or 7 speakers pointing to the height of the human ear or above, and can also output loud sound pressure to meet the long-term stable operation required during movie playback. Requirements. These speakers meet the requirements for building a Dolby Atmos system. Any speaker that accurately reproduces the stereo sound is suitable for restoring sound objects.
Dolby recommends that the original 5.1 or 7.1-channel surround sound box system should be based on the ITU-R BS.775-3 standard. All speakers should ideally be at the same distance from the listening position. If this is not possible, the distance setting in the amplifier should be used to adjust the time delay. All speakers should be at the same height, with a conventional height of 3.9 feet, or 1.2 meters, approximately the average height of the listener's ear position in the sitting position. In particular, the height of the surround back speakers should be the same as the height of the front speakers. If it is not possible to achieve the design of the room, the surround speakers should be higher than the front speakers, but should not be 1.25 times higher than the front speakers. Otherwise, it will affect the reproduction of the sound field above.
Two different ways to set the upper sound field
The overhead speakers have higher requirements for the range of sound radiation, and there are certain requirements for the frequency response range. It is not the average sound field that the ceiling speakers can reach from the top of the head. It is an important advantage of Dolby Atmos compared with the previous surround sound technology. To improve the compatibility of the Dolby Atmos system in room installation, Dolby offers a variety of different ways to solve the sound field setup. One easy solution is to install an overhead speaker on the ceiling. Most high-performance, full-range, wide-difference head speakers are capable.
It should be noted that because Dolby Atmos uses a separate full-range sound object during recording, it can travel anywhere in the entire 3D sound field space. Therefore, the high-frequency extension of the overhead speakers should be as close as possible to other speakers, and the overhead speakers must have a wide high-frequency radiation angle to fully enclose a larger space, and try to replicate the acoustic environment of the Dolby Atmos cinema. At the same time, overhead speakers should be better for full-range speakers.
When installing such an overhead speaker, it is also necessary to make some adjustment according to the range of the sound radiation. If the off-axis diffusion angle of the overhead speaker reaches 45° or more and the frequency band is 100 Hz-10 kHz or more, the vertical direction can be adopted. The installation method below. For head-mounted speakers with a narrow sound diffusion range, it is recommended to have a certain high-frequency directivity adjustment method to point the tweeter to the main listening area. The height of the overhead speaker should be at least twice the height of the human ear, which is 2.4 meters or more. In addition, in order to improve the sound quality and reduce unnecessary audio reflection, it is necessary to make targeted sound absorption or diffusion treatment on the surrounding walls, the ground and the ceiling to reduce the influence of unnecessary sound emission.
Installing a speaker on a ceiling is not suitable for all users. After all, rewiring and fixing on the ceiling is a big problem. As a result, Dolby developed a speaker that can create a head-up sound in a home environment (primarily where the space is not high) through psychoacoustics and sound principles. This special upper sound field speaker does not need to be installed on the ceiling, but is set on the ground, and the effect of reflecting from the ceiling to create a very close to the overhead speaker is called Dolby Atmos enabled speakers. Dolby Atmos effect speakers).
Dolby Atmos enabled speakers The principle of the sound field reflector above the integrated sound field speaker
Independent upper sound field speaker module, need to be used with ordinary speakers
In terms of structure, this special type of speaker can be divided into two categories, one is the integrated speaker, which has the front high-range woofer and the upper sound field unit in the traditional speaker cabinet, and the speaker terminal is also divided into the front. Enter with the top two groups. The other is the independent upper sound field speaker module. Only the built-in upper sound field unit can be used to build the Dolby Atmos system by connecting it to an ordinary speaker. However, in this case, attention must be paid to the low frequency management control of the upper sound field speaker unit. Generally, these speakers are not full frequency output. In addition, it is recommended that you use the same sound field speaker module of the same brand to ensure that the entire system has the same sound.
Comparison and selection of two types of overhead speakers
Dolby recommends choosing to install four upper sound field speakers for more accurate surround and detail effects. The integrated upper sound field speaker connection is different from normal speakers.
What are the two upper sound field settings, independent head speakers and upper sound field speakers, which one is more suitable for ordinary household use? Dolby has done a lot of research in this area. For the new top sound field speakers, Dolby believes that compared to the independent ceiling speakers, the head sounds that are generated according to the diffusivity are closer to the sounds above the head that we usually hear. If the height of the ceiling in the home is originally short, plus the installation of the overhead speaker to use the shelf, the distance from the speaker to the ground is even lower. In this case, the sound from the overhead speaker will be more direct, lacking diffusivity, which is not conducive to the establishment of the entire sense of envelopment. Therefore, in this environment, the upper sound field speaker is a better solution, and the diffusivity of the upper sound field will be even better. This has also been agreed by professional mixers and experts. At the recent CEDIA show, we heard the performance of the upper sound field speakers in the Dolby Atmos room built by Dolby. The diffusivity of the upper sound field is indeed much stronger than that of the independent head speakers.
If you use the upper sound field speakers, Dolby recommends choosing to install four to get more accurate results, especially when used to describe the sound of a flying object above. Two of the four upper sound field speakers should be placed in front of the left and right channel speakers, and the other two in the rear surround speaker position. If only two upper sound field speakers can be used, it is recommended to place them in the front left and right channel speakers. It should be noted that the upper sound field speakers must be installed in pairs, not just one, either in front of or behind the room.
Regarding the upper sound field speakers, both integrated and modular, the height of the placement should be slightly higher than the height of the human ear sitting on the seat, but avoid heights above half the wall. The horizontal distance from the listening position should also be at least 3 feet (approximately 0.9m), preferably at a distance of 5 inches (1.5m) or more. If the height of the upper sound field speaker is beyond the position of the listener's head, consider placing a closer distance. However, when using modular speakers, be aware that they should be placed above the main and surround speakers, or above 0.9m, and placed horizontally, while keeping the unit facing the ceiling.
Room acoustics handling points to consider when using the upper sound field speaker
For optimum performance, the ceiling needs to be flat, without beams or curved heights, within 14 feet (4.27 meters), using acoustically reflective materials such as drywall, plastic, screen or other hard materials. There is no sound absorbing material. The height of the ideal ceiling should be 8-12 feet, which is about 2.44-3.66 meters. Sound absorption or diffusion treatment should be applied to the surrounding walls and floors to solve unnecessary reflection problems to improve the overall sound quality and system performance. When using the upper sound field reflective speaker, the first reflection from the ceiling is needed, and other reflections should be avoided.
Points to note when using an existing surround sound box system
Most existing speakers, including floor boxes, bookshelf boxes, wall-mounted and in-wall speakers, can be implemented with the overhead speakers or the upper sound field speaker module to achieve Dolby Atmos. If the AV amplifier or preamplifier can support the use of more speakers, it can provide more accurate object position and moving sound. It is also important to emphasize again that all speakers in the Dolby Atmos system must be in pairs, with the exception of the center and rear surround speakers.
If the surround sound box system in your home has two ceiling speakers installed, Dolby recommends using two upper sound field launchers at the rear to enhance the details and surround of the upper sound field, or to install two ceilings at the rear. speaker. There is also a case where, for some small audio-visual rooms, the back surround speakers are often installed in the ceiling due to limited space. If you upgrade this speaker system to the Dolby Atmos system, you must turn the original ceiling speaker into a head-mounted speaker, and the surround speaker needs to install a pair on the height of the human ear. If there is no way to add a surround speaker, you can only set a pair of overhead speakers or upper sound field speakers facing the front of the room.
The new configuration of the Dolby Atmos system
Compared to the traditional 5.1 and 7.1 channel configuration, the Dolby Atmos system has a new speaker system configuration, with the number of upper sound field speakers added after 5.1 and 7.1. For example, in the 7.1 system, four upper sound field speakers are used, and this system can be called 7.1.4. For a Hi-End home theater system, a 7.1.4 system will give a better listening experience. Of course, Dolby Atmos can support top-level system configurations up to 24.1.10. It should be noted that although many AV amplifier manufacturers are equipped with more than one subwoofer output for their models, Dolby Atmos technology can only produce one LFE low-frequency effect channel. In the middle of the configuration, the AV amplifier or the preamplifier can be connected to a subwoofer. If it can connect two, it is .2, which is not directly related to the LFE channel.
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