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.

Home theater

A home theater or home theatre is a theater built in a home, designed to mimic (or exceed) commercial theater performance and feeling, more commonly known as a home cinema. Today, home cinema implies a real "cinema experience" at a private home.

Channel

Channel, channels, and similar terms may refer to:

Places

Dolby Digital

Dolby Digital is the name for audio compression technologies developed by Dolby Laboratories. It was originally named Dolby Stereo Digital until 1994. Except for Dolby TrueHD, the audio compression is lossy. The first use of Dolby Digital was to provide digital sound in cinemas from 35mm film prints. It is now also used for other applications such as HDTV broadcast, DVDs, Blu-ray Discs and game consoles.

In the cinema

Batman Returns was the first film to use Dolby Digital technology when it premiered in theaters in the summer of 1992. Dolby Digital cinema soundtracks are optically recorded on a 35 mm release print using sequential data blocks placed between every perforation hole on the sound track side of the film. A constant bit rate of 320 kbit/s is used. A charge-coupled device (CCD) scanner in the image projector picks up a scanned video image of this area, and a processor correlates the image area and extracts the digital data as an AC-3 bitstream. The data are finally decoded into a 5.1 channel audio source. All film prints with Dolby Digital data also have Dolby Stereo analogue soundtracks using Dolby SR noise reduction and such prints are known as Dolby SR-D prints. The analogue soundtrack provides a fall-back option in case of damage to the data area or failure of the digital decoding; it also provides compatibility with projectors not equipped with digital soundheads. Almost all current release cinema prints are of this type and may also include SDDS data and a timecode track to synchronize CD-ROMs carrying DTS soundtracks.

Home cinema

Home cinema, also commonly called home theater or home theatre, refers to home entertainment systems that seek to reproduce a movie theater experience and mood using video and audio equipment in or outside a private home. As of 2015, system users typically use a large projected image from a video projector or a large flat-screen high-resolution HDTV system, a movie or other video content on a DVD or high-resolution Blu-ray disc, which is played on a DVD player or Blu-ray player, with the audio augmented with five or more surround sound speakers and at least one low-frequency subwoofer.

Introduction

In the 1950s, playing home movies became popular in the United States as Kodak 8 mm film projector equipment became more affordable. The development of multi-channel audio systems and later LaserDisc in the 1980s created a new paradigm for home video. In the early to mid-1990s, a typical home cinema in the United States would have a LaserDisc or VHS player fed to a large rear-projection television set. Some people were using expensive front projectors in a darkened viewing room.