杜比全景声技术安装指南
Dolby Atmos? Home Theater Installation Guidelines
October 2014
Contents
1.Background on Dolby Atmos
2.General Dolby Atmos Home Setup Guidelines
?Dolby Atmos Home Playback
?Dolby Atmos Home Theater Speaker Options
?Overhead Speakers
?Alternatives to Overhead Speakers
?Dolby Atmos Enabled Speakers
?Use of Existing Speakers
?Combination: Overhead and Dolby Atmos Enabled Speakers ?Use of Existing Overhead Speakers
3.Standard Speaker Configurations
?Dolby Conventions for Speaker Configurations
?Standard Setup for Both Overhead Speakers and Dolby Atmos Enabled Speakers
4.Additional Speaker Placement Guidelines
?Listener-Level Speaker Placement Guidelines
?Overhead/Height Speaker Placement Guidelines
5.Dolby Surround Upmixer
1.Background on Dolby Atmos
Many leading Hollywood movies, including recent Academy Award? winning films, are presented in Dolby Atmos?, as this revolutionary sound technology allows filmmakers unprecedented realism and creative freedom. With Dolby Atmos, content creators can precisely place and move sounds almost anywhere, including overhead, to create a multidimensional listening experience.
Dolby Atmos technology is now available for the home and will produce a multidimensional listening experience never before experienced in a home theater. And you’ll get a great immersive experience, no matter what kind of Dolby Atmos home theater setup you have. Dolby Atmos content is mixed as audio objects instead of traditional channels. This means the content is not tied to any specific playback configuration. Further, the technology automatically adapts the object audio to take full advantage of the number and placement of your speakers, from systems with five speakers on the floor and two speakers producing overhead sound to a Dolby Atmos system with as many as 24 speakers on the floor and 10 overhead speakers.
Figure 1: At left is a Dolby Atmos system with five speakers on the floor and two overhead speakers; at right is a Dolby Atmos system with up to 24 speakers on the floor and 10 overhead speakers.
Additionally, a new Dolby surround upmixer allows for legacy channel-based content that has not been mixed for Dolby Atmos to be expanded to fill the flexible speaker layouts of a Dolby Atmos system.
These installation guidelines are intended to be a resource for integrating Dolby Atmos into a home theater system and unlocking the potential of this revolutionary audio format. Details include use of conventional overhead speakers and Dolby Atmos enabled speaker technology, which enables you to architect a system capable of reproducing overhead sound, even if you’re not able to put speakers in or on a client’s ceiling.
2.General Dolby Atmos Home Setup Guidelines
The following components are needed to set up a Dolby Atmos home theater system.
1. A source device to play Dolby Atmos content. Many existing devices will work.
2.An A/V receiver (AVR) or processor unit capable of supporting Dolby Atmos.
3.Speakers to reproduce overhead or height audio.
4.Speakers to reproduce listener-level audio. Note: In many use cases, the
customer’s existing speakers may be employed in a Dolby Atmos home
theater.1
Dolby Atmos Home Playback
Source device options to play or stream content
To experience this sound revolution, you’ll need a way to play or stream Dolby Atmos content. There are two initial pathways into the home theater:
1. You can play Dolby Atmos content encoded on a Blu-ray Disc? through an existing Blu-ray Disc player. Be sure you have a recent player that’s fully compliant with Blu-ray? specifications.2
2. You can stream Dolby Atmos content from a compatible game console, Blu-ray, or streaming media player.
In both cases, be sure to set your player to bitstream output and ensure secondary audio functionality is disabled. Connect to your AVR using an HDMI? connection.3
AVR or processor capable of supporting Dolby Atmos
You’ll be able to assemble a system from a wide range of available A/V components, starting with an AVR or preprocessor that supports Dolby Atmos decoding and rendering. Leading AVR manufacturers are introducing products that support Dolby Atmos playback for the home.
1 With the exception of the center and center surround speakers, all speakers in a Dolby Atmos playback system (listener level, overhead, Dolby Atmos enabled) must be added in pairs.
2 You will not need to replace your Blu-ray player as long as it fully conforms to the Blu-ray specification. Current-generation Blu-ray players, and most recent players, are compatible. You should check with the Blu-ray player manufacturer if you encounter problems.
3 Decoding and rendering of Dolby Atmos content is managed entirely by the AVR. To properly pass the Dolby Atmos audio to the AVR, source devices must be connected to the AVR via HDMI 1.
4 or later and set to audio bitstream out. For Blu-ray players, the secondary audio mixing option must be disabled.
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the listener level in this document. Any speaker type that is capable of accurately representing a stereo pan is suitable to reproduce objects.
As in the past, the placement of all listener-level speakers should follow these recommendations, which are based on ITU-R BS.775-3:
?The speakers located in the front of the room shall be used as a reference point. All speakers in the listener plane should ideally be equidistant from the listener position. If this is not possible, compensating for distance may be
used to time align the arrival of audio from each speaker to the listener.
?All listener speakers should be at the same height, typically 3.9 feet (1.2 meters), which is ear level for the average seated listener (as defined in ITU-R BS.1116-1).
If possible, the height of the rear speakers should be the same as the height of the front speakers. If the room design makes this impractical, or impossible, the rear speakers may be higher than the front speakers. However, it is suggested that the height of the rear speakers not be more than 1.25 times the height of the front speakers.
Overhead Speakers
Overhead sound is a vital part of the Dolby Atmos experience. There are a variety of options for adding this capability to a room.
One solution is to install speakers overhead. Most high-power, full-frequency conventional overhead speakers with wide dispersion characteristics will work in a Dolby Atmos home theater.
Characteristics
Dolby Atmos audio is mixed using discrete, full-range audio objects that may move around anywhere in three-dimensional space. With this in mind, overhead speakers should complement the frequency response, output, and power-handling capabilities of the listener-level speakers. Choose overhead speakers that are timbre matched as closely as possible to the primary listener-level speakers. Overhead speakers with a wide dispersion pattern are desirable for use in a Dolby Atmos system. This will ensure the closest replication of the cinematic environment, where overhead speakers are placed high above the listeners.
Mounting considerations
If the chosen overhead speakers have a wide dispersion pattern (approximately
45 degrees from the acoustical reference axis over the audio band from 100 Hz to 10 kHz or wider), then speakers may be mounted facing directly downward. For speakers with narrower dispersion patterns, those with aimable or angled elements should be angled toward the primary listening position.
Room treatment considerations for use of overhead speakers
For optimal performance, the overhead speakers should be at least two times the height of the listener’s ear level (this generally applies to on-ceiling speakers, which may be installed lower than the actual ceiling height).
Sound-absorbing and sound-diffusing treatment for handling reflections from the walls, floor, and ceiling are recommended to improve sound quality and reduce unwanted audio reflection.
Alternatives to Overhead Speakers
Installing overhead speakers may not be possible or desirable for your client. Installing speakers overhead and running the necessary wiring can be expensive and time consuming. If your client rents the home, the property owner may not allow it. And if the ceiling is made of a material such as concrete or brick, installing speakers overhead may not be possible. Finally, your client may not like the look of overhead speakers.
Dolby Atmos Enabled Speakers
Through our knowledge of psychoacoustics and sound physics, we’ve developed speakers that can create overhead sound even though they’re only a few feet off the floor. Dolby specifies filtering characteristics for these speakers that amplify the perception of sound originating overhead. Employing a predetermined angle of incidence in the speaker cabinet, the speakers direct sound upward, where it reflects off the ceiling to produce an incredibly accurate and lifelike recreation of overhead sound. The performance of Dolby Atmos enabled speakers must be experienced to be believed.
Integrated speakers
You will be able to select integrated Dolby Atmos enabled speakers that include both traditional front-firing speakers and upward-firing speakers in a single speaker
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Comparison to overhead speakers
Dolby Atmos enabled speakers produce slightly more diffuse overhead audio that is quite lifelike and, in some cases, may be preferable to the sound that originates from overhead speakers.
If your ceiling is low or you have to mount the loudspeakers on overhead trusses or brackets, overhead speakers may be too close to you as you listen. The audio may be distracting because you’ll hear, directionally, what each speaker is producing instead of feeling immersed in an atmosphere in which sounds occur naturally overhead.
In this environment, Dolby Atmos enabled speakers may be a better solution for reproducing the height plane of sound you would hear in a cinema, where the overhead speakers are located high in the auditorium and are naturally creating a more diffuse experience. Audio mixers and experts who have auditioned Dolby Atmos enabled speakers agree that the sound these speakers produce can be preferable to the sound of dedicated overhead speakers.
Dolby Atmos enabled speaker positioning
Dolby recommends installation of four Dolby Atmos enabled speakers whenever possible. Use of four speakers will make the placement of overhead sounds more accurate, and you’ll get more precise, realistic sounds when an object, such as a helicopter, passes overhead. Two of the speakers (whether they are integrated
speakers or add-on modules) should be in the front left and front right speaker locations of your system. The other two should be positioned in the surround sound speaker locations, ideally at the rear surround speakers, if you have them.
If using only two Dolby Atmos enabled speakers, place the Dolby Atmos enabled speakers at the front left and front right speaker locations. Note: With the exception of the center and center surround speakers, all speakers in a Dolby Atmos playback system (listener level, overhead, and Dolby Atmos enabled) must be added in pairs. Dolby Atmos speakers should be located in the front left and front right and left rear surround and right rear surround locations in a 7.1.4 playback system.
Placement height
For optimal effect and to minimize direct radiating audio at listener level, place Dolby Atmos enabled speakers at or slightly above the height of your ears when seated. Avoid placing the Dolby Atmos enabled speakers higher than one-half the height of your wall.
Placement relative to listeners
To avoid an unwanted proximity effect, make sure the speakers are at least 3 feet (0.9 meter) away from listening positions, ideally 5 feet (1.5 meters) or more. This distance may potentially be less if the upward-firing driver(s) of the Dolby Atmos enabled speaker is placed well above the level of the closest listener’s head.
Positioning of add-on modules
If you’re using add-on modules, place them either on top of the front and surround (ideally, rear surround) speakers or within 3 feet (0.9 meter) of those speakers. Dolby Atmos enabled speakers should be mounted horizontally so that the driver is facing toward the ceiling.
Room treatment considerations for use of Dolby Atmos enabled speakers
For optimal performance, the ceiling should be flat (not angled or vaulted), with a height of 14 feet (4.27 meters) or less, and made of an acoustically reflective material (drywall, plaster, hardwood, or another rigid, non–sound-absorbing material). The ideal ceiling height is between 8 and 12 feet (2.44 and 3.66 meters).
Sound-absorbing and sound-diffusing treatment for handling unwanted reflections from the walls and floor is recommended to improve sound quality and system performance. When using Dolby Atmos enabled speakers, first audio reflection from
the ceiling is desired; audio reflections from elsewhere within the room should be avoided.
Bass management with Dolby Atmos enabled speakers
Be mindful to employ proper bass management when installing Dolby Atmos enabled speakers in the client’s system. Typically, these speakers are not full range, and manufacturer documentation should be consulted for specific details on each model. Integrated speakers may direct low frequencies intended for the elevation drivers to the primary speakers; in other instances, including when modules are employed, you will have to perform bass management in the AVR or preprocessor.
Use of Existing Speakers
Most existing speakers within current home theaters will work for Dolby Atmos playback. Floor-standing, stand-mounted, on-wall, and in-wall speakers that currently produce audio at the listener level can be complemented with overhead speakers and/or Dolby Atmos enabled speakers to generate the height plane of overhead sounds. If the AVR or preprocessor supports them, more speakers may also be added at listener level to add greater precision to object audio placement and movement. With the exception of the center and center surround speakers, all speakers in a Dolby Atmos playback system must be added in pairs.
Front height mounted speakers
Most AVRs will support the use of front height (Dolby? Pro Logic? IIz) mounted speakers with Dolby Atmos playback; however, Dolby recommends the use of either overhead or Dolby Atmos enabled speakers to create the most lifelike and enveloping audio experience. Front height speakers may be used in conjunction with overhead speakers in larger room installations that can support a greater number of overhead/height outputs.
Combination: Overhead and Dolby Atmos Enabled Speakers
In some instances, a home theater system may already have overhead speakers that can be used to generate overhead audio. In this case, Dolby Atmos enabled speakers may be used to complement existing overhead speakers to create a full four-speaker height experience. If existing overhead speakers are in the front of the room, then Dolby Atmos enabled speakers may be used in the rear of the room, and vice versa.
Use of Existing Overhead Speakers
In some existing home theater systems, overhead speakers are employed to generate audio that would otherwise be created by listener-level speakers (for example, left/right surround speakers). When transitioning to Dolby Atmos, existing overhead speakers should only be repurposed as overhead outputs if a corresponding listener-level speaker can be added to assume the previous overhead speaker feed.
For example, if two overhead speakers located toward the rear of the room are currently used to reproduce left/right surround outputs, they should be used as overhead speakers only if replacement left/right surrounds can be added at the listener level. If this is not possible, the overhead speakers should continue to be used for left/right surround outputs. In this case, overhead sound can be achieved by installing additional overhead speakers, Dolby Atmos enabled speakers, or modules in the front speaker locations.
3.Standard Speaker Configurations
Dolby Conventions for Speaker Configurations
With the debut of Dolby Atmos, there is a new method of referring to surround sound speaker configurations (see the “Dolby Atmos for the Home Theater” white paper for more details). It is based on the standard nomenclature (stereo, 5.1, and 7.1) but adds a number at the end to specify the number of height speakers you employ in the playback system (for example, 7.1.4).
While manufacturers may decide to support more than one subwoofer output, Dolby Atmos technology generates a single Low Frequency Effects (LFE) signal. Figures 5, 6, and 7 show the most common speaker layouts in a Dolby Atmos home theater system.
Figure 5: A traditional 7.1 speaker layout with four Dolby Atmos enabled speakers (7.1.4).
Figure 6: A traditional 5.1 speaker layout with four overhead speakers (5.1.4).
Figure 7: A traditional 5.1 speaker layout with two Dolby Atmos enabled speakers (5.1.2).
Standard Setups for Both Overhead Speakers and Dolby Atmos Enabled Speakers Images of standard setups follow for the most common speaker configurations and are provided for both overhead speakers and Dolby Atmos enabled speakers: 5.1.2 (Fig. 8, Fig. 9), 5.1.4 (Fig. 10, Fig. 11), 7.1.2 (Fig. 12, Fig. 13), 7.1.4 (Fig. 14, Fig.
15), 9.1.2 (Fig. 16, Fig.17), and 9.1.4 (Fig. 18, Fig. 19).
Figure 8: Standard 5.1.2 setup with overhead speakers.
Figure 9: Standard 5.1.2 setup with Dolby Atmos enabled speakers.
Figure 10: Standard 5.1.4 setup with overhead speakers.
Figure 11: Standard 5.1.4 setup with Dolby Atmos enabled speakers.
Figure 12: Standard 7.1.2 setup with overhead speakers.