Introduction
Surround sound was used in movies since the 1950s, so as to give a more practical cinema occurrence. Later, the fame of surround sound led to its advancement from movie halls to home theatre. It was designed with a medium having many channels for producing sound for example the Dolby ProLogic. This was a result of much advancement in sound technology (Adams & Wolenik 56). Up to the 1990s, many surround sound formats were founded on matrix implying that, details from the entire channel were programmed as a two-channel hi-fi. In the mid-1990s, distinct programming that had independent channels of audio was initiated by Dolby Laboratories and Digital Theatre Systems.
One of the main purposes of using surround sound is to improve the hearing episode. Surround sound improves the quality of the sound produced and incorporates the listeners more. In addition, surround sound improves live concerts done on CD/DVD by positioning the listener in the hall, while the show is on stage the listeners and hall sounds are heard in the surrounds. Surround sound function because of how people recognize the sound. One way people perceive sound is by audible periphery where each ear works as a single recipient. In binaural perception, people acknowledge the similar sound using both ears. Finally, in spatial perception, people recognize sounds in space and around them (Rumsey 35).
What is surround sound?
There are various methods of producing a sound recording. One of the easiest ways used in the past movies was known as mono. This implied that all the sound was made into a single channel and was listened to busing one speaker. On the other hand, if the sound is heard using two speakers then the system is known as a stereo. When sound is heard from a stereo it forms an experience of a live performance (Newell 49).
Surround sound systems use this technology and advance it further. This is done by incorporating more soundtracks so that the sounds come from many directions. The phrase surround sound means precise multi-channel system made by Dolby Laboratories; it was applied as a common phrase for theatre and home theatre multi-channel sound systems (Holma 75).
There are unique microphones that will copy surround sound, though this is not a suitable method to create a surround sound track. The majority of the films incorporate surround sound channels and are made in an integration studio. The sound technicians use various audio recordings to determine which audio tracks to use.
Historical background
In the early 1950s, the first money-making multichannel sound design was made for film use. Many Hollywood films were recorded with multichannel designs. A variety of theatre designs were formed during this period, comprising the popular Cinerama and Cinemascope, however many of them applied similar knowledge of sound technology. In general, these technologies were called stereophonic sound. Quad was the first design made in the 1970s. However, as a result of incompatibility matters in the transmission process, the Quad failed to function properly. In the 1970s, Dolby made plans of solving the incompatibility problems by establishing a new design known as the Dolby stereo, a unique encoding system that later became very famous.
With the design of CDs in the early 1980s, stereo devices became popular. With the advent of DVDs in 1995 people began to spread multichannel sound in digital design. In 1992, Dolby labs formed a system known as Dolby Digital that provided good quality multichannel surround occurrence. The Dolby Digital was selected as the main audio coding design for DVDs and for digital audio broadcasting (Collins 77).
Working of surround sound
Surround sound systems are formed through a precise combination of mono and stereo soundtrack. Recordings are done straight to the separate design at the supply. For example, recording a live show to a 5.1 design produces a soundtrack that gets the initial sound of the live performance (Collins 70).
There are two savors of surround sound: matrix and discrete. The matrix method utilizes a unique programming style that incorporates the multichannel recordings to the stereo. Decoders in the audience reform the incident. But, the design is associated with a number of challenges. Some devices may be fixed in the incorrect systems. This may result in the failure of the whole system.
THX Surround
The surround systems use a 5.1 channel pattern that gives a multi-dimensional sound occurrence. The sound is written using five major controls: left, center, right, left surround, and right surround. Moreover, an extra control known as the low-frequency effects is created for the subwoofer. The first movie was made in 1976 and utilized the Dolby Stereo encoding for total sound effects. Nevertheless, George Lucas acknowledged he was not satisfied with the sounds produced by the surround speakers. Therefore he made plans of enhancing it. As a result THX system was designed (Newell & Holland 99).
Lucasfilm initiated the Home THX certification program in 1990 for those who required theatre incidents in their homes. Tomlin discovered there was a difference between movies watched at the movie theatre compared to those watching at home The explanation was that in the movie theatres, the room is big with an array of surround speakers, while the home atmosphere is small with only two surround speakers. THX formed created engineering ideas and innovative advancements that would create a true movie experience in the home environment (Rumsey & McCormick 30).
In 1999 the THX Surround EX was introduced. It was managed by Dolby Labs and Lucasfilm THX. Surround THX provided a more realistic and flexible technique especially when forming films. Surround EX forms a real 360-degree surround sound incident incorporating a rear channel. This channel is formed by matrix programming the surround back into the surround left and surrounds right controls (Gilbert & Haeberl 112).
Matrixed surround sound systems
Systems that are matrixed imply that information can be transferred using fewer tracks compared to the original supply. This has some challenges and therefore requires proper demixing; however, this method has been applied broadly for several years, due to the lack of multichannel media in many places (Adams & Wolenik 60).
The Dolby labs were responsible for the creation of cinema surround sound systems, and then for the field of home theatre. The initial Dolby double speaker system had various designs of movie sound with three to six tracks. Dolby surround was initiated in 1982 as a way of copying the impacts of Dolby stereo in a home environment. Basically, the same approach of matrix programming was applied; therefore movies transmitted to television design could be programmed at home like in the cinemas (Newell & Holland 115).
Digital surround sound formats
The matrix surround methods are making people be innovative and think of new ideas like digital designs. The digital designs allow many channels to be carried discretely, by allowing a two-channel control. Though it is required that surround sound signals are transported and kept in a distinct, full-resolution design this can result in usage of many volumes, which is expensive for normal broadcasting or home applications (Rumsey 40). As a result, many methods have been designed so that data is digitally recorded as a small bit compared to the supply, with reduced loss of sound appeal.
The Dolby AC-3 codec is used to create 5.1 surround sounds. It was created in 1992 to support multichannel systems on a 35mm layer. Later, it was used to DTV, HDTV, and DVD. The design uses both stereo and discrete multichannel equipment. The encoding system is used to condense audio recordings with less effect on the resultant sound value (Rumsey & McCormick 35).
The method works by sorting the audio recording into discrete groupings. The encoder checks the major frequencies at a particular position within a given time period. The encoder assigns bits to what is very important. As a result, the sorting procedure minimizes the file capacity significantly. The AC-3 also handles metadata that is found in the data track. The metadata instructs the AC-3 on how to utilize the surround sound. The Dolby encoder device was initially hardware equipment and was later swapped with software devices. Dolby presently authorizes its AC-3 encoder to many software traders so that they can program their surround sound systems (Gilbert & Haberl 118).
Future prospects
In the future engineers are planning to create a wireless surround sound speakers. This new technology which has built-in decoders has been used in many famous companies especially in China. Wireless surround sound systems are aimed at giving advanced equipment to people, especially for home use. This new technology has many benefits: speakers can be positioned anywhere and no wires are used to transmit information.
References
Adams John, Wolenik Robert. Build your own home theater. USA: Butterworth- Heinemann, 2002.
Collins, Karen. Game sound: an introduction to the history, theory and practice of sound design. USA: Massachusetts Institute of Technology, 2008.
Gilbert Pupa, Haeberl Willy. Physics in the arts. USA: Elsevier Academic Press, 2008.
Holma, Tomlinson. Surround sound: up and running. USA: Focal Press, 2008.
Newell Richard, Holland Keith. Loudspeakers: for music recording and reproduction. USA: Elsevier Academic Press, 2007.
Newell, Philip. Recording Studio Design. USA: Elseveir Ltd, 2008.
Rumsey Francis, McCormick Tim. Sound and Recording.. UK: Focal Press, 2009.
Rumsey, Francis. Spatial audio. UK: Focal Press, 2001.