Surround sound

Surround sound is a technique for enriching the sound reproduction quality of an audio source with additional audio channels from speakers that surround the listener (surround channels), providing sound from a 360° radius in the horizontal plane (2D) as opposed to "screen channels" (centre, [front] left, and [front] right) originating only from the listener's forward arc.

Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and presents a fixed or forward perspective of the sound field to the listener at this location. The technique enhances the perception of sound spatialization by exploiting sound localization; a listener's ability to identify the location or origin of a detected sound in direction and distance. Typically this is achieved by using multiple discrete audio channels routed to an array of loudspeakers.

There are various surround sound based formats and techniques, varying in reproduction and recording methods along with the number and positioning of additional channels.

Sound

In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a medium such as air or water. In physiology and psychology, sound is the reception of such waves and their perception by the brain.

Acoustics

Acoustics is the interdisciplinary science that deals with the study of mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound, and infrasound. A scientist who works in the field of acoustics is an acoustician, while someone working in the field of acoustical engineering may be called an acoustical engineer. An audio engineer, on the other hand is concerned with the recording, manipulation, mixing, and reproduction of sound.

Applications of acoustics are found in almost all aspects of modern society, subdisciplines include aeroacoustics, audio signal processing, architectural acoustics, bioacoustics, electro-acoustics, environmental noise, musical acoustics, noise control, psychoacoustics, speech, ultrasound, underwater acoustics, and vibration.

Dolby Atmos

Dolby Atmos is the name of a surround sound technology announced by Dolby Laboratories in April 2012 and released in June of the same year, first utilized in Pixar's Brave.

History

The first installation was in the Dolby Theater in Hollywood, California, for the premiere of Brave in June 2012. Throughout 2012, it saw a limited release of about 25 installations worldwide, with an increase to 300 locations in 2013. There were over 2,100 locations as of February 2015. Dolby Atmos has also been adapted to a home theatre format.

Technology

The Dolby Atmos technology allows up to 128 audio tracks plus associated pan metadata to be distributed to theaters for optimal, dynamic rendering to loudspeakers based on the theater capabilities. That is, Dolby Atmos enables the re-recording mixer using a Pro Tools plugin (available from Dolby) or a Dolby Atmos equipped large format audio mixing console such as AMS Neve's DFC or Harrison's MPC5, to designate a particular location in the theater, as a three-dimensional placement, where each dynamic sound source should seem to be coming from. Sounds that are not dynamically moving, such as ambient sounds and center dialogues, are still separately pre-mixed in a traditional multichannel format. During playback, each theater's Dolby Atmos system renders all dynamic sounds, from the pan metadata, in real-time to make it seem like each sound is coming from its designated spot, with respect to the speakers present in the target theater. By way of contrast, traditional multichannel technology essentially burns the audio tracks into a fixed number of channels during post-production. This has traditionally forced the re-recording mixer to make up-front assumptions about the playback environment that may not apply very well to a particular theater (to the extent its capabilities differ from the mixing stage where the mixer was working).

7.1 surround sound

7.1 sound is the common name for an eight-channel surround audio system commonly used in home theatre configurations. It adds two additional speakers to the more conventional six-channel (5.1) audio configuration. As with 5.1 surround sound, 7.1 surround sound positional audio uses the standard front, center, and LFE (subwoofer) speaker configuration. However, whereas a 5.1 surround sound system combines both surround and rear channel effects into two channels (commonly configured in home theatre set-ups as two rear surround speakers), a 7.1 surround system splits the surround and rear channel information into four distinct channels, in which sound effects are directed to left and right surround channels, plus two rear surround channels. In a 7.1 surround sound home theatre set-up, the surround speakers are placed to the side of the listener's position and the rear speakers are placed behind the listener. In addition, with the advent of Dolby Pro Logic IIz and DTS Neo:X, 7.1 surround sound can also refer to 5.1 surround sound configurations with the addition of two front height channels positioned above the front channels or two front wide channels positioned between the front and surround channels.

Sound design

Sound design is the process of specifying, acquiring, manipulating or generating audio elements. It is employed in a variety of disciplines including filmmaking, television production, theatre, sound recording and reproduction, live performance, sound art, post-production, radio and video game software development. Sound design most commonly involves the manipulation of previously composed or recorded audio, such as sound effects and dialogue. In some instances it may also involve the composition or manipulation of audio to create a desired effect or mood. A sound designer is one who practices the art of sound design.

History

The use of sound to evoke emotion, reflect mood and underscore actions in plays and dances began in prehistoric times. At its earliest, it was used in religious practices for healing or just for fun. In ancient Japan, theatrical events called kagura were performed in Shinto shrines with music and dance.

Plays were performed in medieval times in a form of theatre called Commedia dell'arte, which used music and sound effects to enhance performances. The use of music and sound in the Elizabethan Theatre followed, in which music and sound effects were produced off stage using devices such as bells, whistles, and horns. Cues would be written in the script for music and sound effects to be played at the appropriate time.