Dolby Atmos: The Future of Cinema

Sound effects have become an integral part of modern films. With each passing year they become more and more realistic, and what we hear now in the film - is the result of hard work of many people over the century

. However, the proliferation of the Internet and the advent of services like Netflix, Cinema popularity began to decline gradually. In an attempt to support this type of business, several new technologies have been implemented. In addition to the IMAX, which offers high-quality 3D-images, there were also interesting solutions in the field of sound.

According to experts, a new milestone in the development of the cinema will be multi-channel audio format Dolby Atmos. Presented in Dolby Atmos famous Hollywood cinema Dolby Theatre in April 2012. The first painting, whose soundtrack was made in this format was the cartoon «Braveheart» ( «Brave») Pixar studio. While in 2012 the number of cinemas using the Atmos, does not exceed 25 units worldwide, in 2013 their number increased to 300, and has continued to grow.

Since the days of "Braveheart" with the use of new technologies have been filmed such movies as "Guardians of the Galaxy», «Star Trek: Nemesis" and "Life of Pi". On the main difference Atmos on other existing multi-standards in an interview with US magazine Sound & amp; Vision told Brett Crockett (Brett Crockett), director of sound research laboratories Dolby: «Dolby Atmos - this is the first sound system for the theater, which is not based on the channels, and audio objects . Crying baby, the sound of a helicopter, a car horn - all

audio objects. " Sound using Dolby Atmos, decide exactly where the sound source (in other words, constitute a 3D-map of the sound space), and determines at what trajectory it moves. It turns out that you can choose from a speaker sound will come. If necessary audiokolonki inoperable or missing, the system will automatically generate "phantom" speakers so that the sound is still fed from the right place.

Thus, in the cinema content it does not fall in the form of pre-recorded tracks, and in a plurality of audio files and related information on the space-time coordinates. This information falls into the audio processor, which knows exactly where the speakers (installed and calibrated in the cinema installation), and he calculates where and how you want to send audio information.



tiny white line at the top of the cube is flying a helicopter in 3D-space. Points are left speakers. The subwoofer and the two left upper speaker at this moment active

In addition to Dolby audio objects allows you to work with the usual audio channels (The Beds), do not require spatial (environmental noise, music), which allows you to create the most immersive full picture.



For each cinema created the project in accordance with the specifications, which is determined by the number and location of the speakers required for correct playback format. Each project is approved by the authorized consultant Dolby.

Generally Dolby keeps all projects under the direct control. Cinemas approved by Dolby specialists who go to the place, and take measure the room. Thus there is a check of the configuration and equipment - each speaker and amplifier

. The representatives of the company has a special measuring system, consisting of 8 microphones, which record the parameters and the delay of each speaker sound. If all speakers endorsed, the process begins in groups arrays 5.1, 7.1 and 9.1. After that, the room setting is stored in the processor is filled Configuration Protocol. In other words, to assign the room status Dolby Atmos, the company checks all the characteristics.

When you configure the processor entered data on the size of the hall, on the number and location of placement of the speakers, all the characteristics of the speakers and amplifiers associated with them, etc. Hall describes the CPU so as to exclude the possibility of errors.



Dolby Atmos can work with 128 soundtracks, which are processed according to their type. Static track at once "fixed" for individual PC Speaker or the whole of their arrays. As for the audio objects, they are processed in real time according to the configuration of the cinema. Total Dolby processor can output sound to the speakers 64 at the same time.



Audio equipment and facilities in various theaters can dramatically vary in size and shape, so that the sound delivered maximum fun, the developers have prepared the requirements for the placement of the speakers.



location scheme of sound equipment in the cinema

To sound transitions were smooth as possible, the company recommends that you set for the screen two additional speakers (marked in green) - this is especially important for the cinema, the screen width which exceeds 12 meters. Also, all the "screens" horns should be deployed in one particular point located somewhere in the room to cover all of the seats.

Front subwoofers are grouped into a single array of desired power, which is slightly shifted away from the axis of symmetry - it helps reduce the risk of standing waves

. As for the surround speakers, along the walls, then they must be connected to an individual channel gain, configured in accordance with the parameters of the maximum noise power specified by the manufacturer of audio.

Side audio should be located along the entire length of the wall to ensure a decent sound coverage and form a straight line, as shown in the figure below. The slope of the speakers should be oriented along the axis of the ear spectator, sitting in the far place from the opposite side of the hall.

Most surround speakers are not capable of producing powerful low frequency, because in the back of the audience must add two additional subwoofer.



As regards acoustic ceiling, the upper speakers should strictly be located symmetrically about the axis of the room and along its entire length. Moreover, the distance between two rows of columns should be slightly greater than that between the additional speakers for TV systems. Again, the speakers in the front and rear of the audience must be deployed in the direction of a common point.

According to the company Dolby, the viewer sitting in a well-equipped room, there is a feeling as if he was "surrounded by an infinite number of speakers" - it allows him to immerse themselves in what is happening on the screen

. Rui Soares (Rui Soares) and Dipankar Grover (Dipankar Grover) said that the technology gives a great impression and distinguish Atmos system from other systems a breeze. «Dolby Atmos can take you right into the thick of events occurring on the screen," - exclaims Grover

. However, to give such a magical impression of the system can only be set up with the proper equipment and exhibiting correct sound levels. Otherwise, the technology turns into another way of "handling" the viewer with a loud sound, just with an even greater number of directions.

Sound - an interesting thing. It is incredibly important for the perception of the film, but when done correctly, you will not even notice. However, if you do pay attention to it, you will discover many interesting things. Sound - is the main weapon of cinemas, which demands the same amount of attention as the image of the film, and Dolby Atmos technology offers in this area great potential

P.S.. More material on the topic of audio -. Our blog "World Hi-Fi"

Source: geektimes.ru/company/audiomania/blog/274248/