The most widely used Home Entertainment process. Produces a surrounding sound field with Dolby Surround or Dolby Stereo encoded software. This includes practically all major films from the late seventies and onwards available on VHS videotape, LaserDisc, DVD or from stereo TV. It has 4 perceivable channels of sound all derived from a stereo sound track, (Left Front, Centre, Front Right and Rear Surround) This is achieved by redirecting out of phase information (Normally deliberately encoded in to the stereo tracks) to the rear speakers. Information going to the centre channel (Pro-Logic) processes and mixes all information that is lacking in any stereo content Dolby Pro Logic 2 is the updated version of Pro-Logic that gives stereo surround speaker channels .
High-quality surround sound system for movies and TV programs. A Dolby Pro-Logic audio signal can be carried either over an analog or a digital transmission.
The VHS standard for delivering surround sound. All DD 5.1 receivers can decode Pro-Logic. Some older DVDs may be encoded with digital Pro-Logic signals.
Uses an extra centre speaker at the front, which locks dialogue to the screen. Now mainly used when viewing material sourced from video tape or off-air broadcasts, or with older soundtracks on DVD lacking discrete surround channels.
Most common surround format. It consists of four channels of sound: left/right front channels, a center channel, and one surround channel.
Most popular surround format. Almost any receiver nowadays has it. Uses matrixed surround in order to encode four channels of sound: left/right front channels, a center channel, and one surround channel. It is quite a common occurrence to see two speakers used for the one surround channel however, as well as a subwoofer to supplement the speakers.
Is an Analogue surround sound process that delivers four channels of information from two channel soundtracks.
Analogue surround-sound format.
DPL is a forerunner to Dolby Digital that 'steers' sound from a stereo source to the front, centre and mono surround channels via an analogue matrix.
The older Dolby Pro-logic coding scheme is a matrixed system in which the four channels of information(left,right,center,surround) are folded into two discrete channels so they can be encoded onto the source material such as a broadcast,VCR,DVD or laser disc. The Pro-logic processor then extracts the four channels of data from the two encoded channels and directs them to the speakers. The rear surround channel is divided over two speakers, however it is a mono signal. Pro-logic II is a variation of the original scheme which allows more power and presence to the surround field.
Home Cinema surround sound format that consists of a front or center channel for on-screen dialogue, front left and right channels and a rear surround channel to carry the rear surround effects.
A more advanced form of Dolby Surround encoding and decoding in which there is an additional front center channel containing dialogue information.
Analog surround sound format using matrix surround technology to encode four channels of audio information (left, center, right and surround) onto two channels creating a surround sound sonic environment for properly encoded movies and other programming (see Matrix Surround Sound).
Is a four-channel surround sound system available from stereo TV broadcasts, VHS movies and most DVDs. It sends information to speakers at front left, front right, front center and two rear speakers which share a mono signal.
The first sound system to use rear channels for an immersive listening experience. This analog surround sound format uses 3 speakers for the front soundstage (left, center & right) and 2 speakers for the back. The rear speakers are fed the same signal, resulting in a mono surround stage. Dolby Pro-logic is used by broadcasters worldwide and is the choice of the video industry.
