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Manage your Home Electronic Systems

Home audio systems are audio electronics intended for home entertainment use, such as shelf stereos and surround sound receivers. Home audio generally does not include such standard equipment such as built-in television speakers, but rather accessory equipment, which may be intended to enhance or replace standard equipment, such as standard TV speakers. Since surround sound receivers, which are primarily intended to enhance the reproduction of a movie, are the most popular home audio device, the primary field of home audio is home cinema.

The first documented use of surround sound was in 1940, for the Disney studio's animated film FantasiaWalt Disney was inspired by Nikolai Rimsky-Korsakov's operatic piece,Flight of the Bumblebee to have a bumblebee featured in his musical Fantasia and also sound as if it was flying in all parts of the theatre – the unsuccessful experimentation led to the music being excluded from the film and the eventual invention of "surround sound".

The initial multichannel audio application was called 'Fantasound', comprising three audio channels and speakers. The sound was diffused throughout the cinema, initially by an engineer using some 54 loudspeakers. The surround sound was achieved using the sum and the difference of the phase of the sound. In the 1950s, the German composer Karlheinz Stockhausen experimented with and produced ground-breaking electronic compositions such as Gesang der Jünglinge and Kontakte, the latter using fully discrete and rotating quadraphonic sounds generated with industrial electronic equipment in Herbert Eimert's studio at the Westdeutscher Rundfunk (WDR). Edgar Varese's Poeme Electronique, created for the Iannis Xenakis designed Philips Pavilion at the 1958 Brussels World's Fair, also utilised spatial audio with 425 loudspeakers used to move sound throughout the pavilion. There are also many other composers that created ground-breaking surround sound works in the same time period.

In 1978, a concept devised by Max Bell for Dolby Laboratories called "split surround" was tested with the movie "Superman". This led to the 70mm stereo surround release of "Apocalypse Now," which became the first formal release in cinemas with 3 channels in the front and 2 in the rear. The "Apocalypse Now" encoder/decoder was designed by Michael Karagosian, also for Dolby Laboratories. The surround mix was produced by an Oscar-winning crew led by Walter Murch for American Zoetrope. The format was also deployed in 1982 with the stereo surround release of Blade Runner.

5.1 surround sound originated in 1987 at the famous French Cabaret Moulin Rouge. A French engineer, Dominique Bertrand used a mixing board specially designed in cooperation with Solid State Logic, based on 5000 series and including 6 channels. Respectively: A left, B right, C centre, D left rear, E right rear, F bass. The same engineer had already achieved a 3.1 system in 1974, for the International Summit of Francophone States in Dakar Senegal.

Surround sound is created in several ways. The first and simplest method is using a surround sound recording technique—capturing two distinct stereo images, one for the front and one for the back or by using a dedicated setup, e.g. an augmented Decca tree, the OCT (Optimized Cardioid Triangle) or XYtri configuration—and/or mixing-in surround sound for playback on an audio system using speakers encircling the listener to play audio from different directions. A second approach is processing the audio with psychoacoustic sound localization methods to simulate a two-dimensional (2-D) sound field with headphones. A third approach, based on Huygens' principle, attempts reconstructing the recorded sound field wave fronts within the listening space; an "audio hologram" form. One form, wave field synthesis (WFS), produces a sound field with an even error field over the entire area. Commercial WFS systems, currently marketed by companies sonic emotion and Iosono, require many loudspeakers and significant computing power.

The Ambisonics form, also based on Huygens' principle, gives an exact sound reconstruction at the central point; less accurate away from center point. There are many free and commercial software programs available for Ambisonics, which dominates most of the consumer market, especially musicians using electronic and computer music. Moreover, Ambisonics products are the standard in surround sound hardware sold by Meridian Audio In its simplest form, Ambisonics consumes few resources, however this is not true for recent developments, such as Near Field Compensated Higher Order Ambisonics. Some years ago it was shown that, in the limit, WFS and Ambisonics converge.

Finally, surround sound can also be achieved by mastering level, from stereophonic sources as with Penteo, which uses Digital Signal Processing analysis of a stereo recording to parse out individual sounds to component panorama positions, then positions them, accordingly, into a five-channel field. However, there are more ways to create surround sound out of stereo, for instance with routines based on the QS and SQ Quad routines, where instruments were divided over 4 speakers in the studio. This way of creating surround with software routines is normally referred to as "upmixing".

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