Intelligent Sound

Dolby Digital Plus is a digital audio compression scheme, abbreviated as DD+ or E-AC-3 (Enhanced AC-3). The enhanced coding system is based on the AC-3 codec and offers increased bitrates (up to 6.144 Mbit/s). The system also supports up to 13.1 audio channels and offers improved coding techniques to reduce compression artifacts. Although E-AC-3 decoders can transcode to AC-3 or DTS for equipments connected via S/PDIF, DD Plus is not backward compatible with the current AC-3 hardware.

A real-time hardware encoding technology, Dolby Digital Live (DDL) was developed by Dolby Laboratories for interactive media like video games.The technology converts audio signals on a PC or game console into a 5.1 channel 16-bit/48 KHz Dolby Digital format at 640 kbps. This is transported via a single S/PDIF cable. In other words, the technology converts any audio signal into a Dolby Digital bitstream and transports it for a playback through a home theater system.

Dolby Digital EX was created for cinema and is the home theatre implementation of Dolby Digital Surround EX technology. It resembles Dolby Pro-Logic format that used matrix technology to add a center channel and a single rear surround channel to stereo soundtracks. The standard 5.1 channel Dolby Digital codec is extended in this version with matrixed rear channels that create 6.1 or 7.1 channel output. The additional center surround channel is reproduced through one or two speakers that provide an extra dimensional detail and a surround sound effect.

Dolby Laboratories have developed a series of data/audio compression technologies and Dolby Digital is the marketing name for the series. Also abbreviated as AC-3, it is the common version that contains up to six channels of sound. The mode generally used involves five channels for normal-range speakers and one channel for the subwoofer driven low-frequency effects. The normal-range speakers have a frequency range between 20 Hz – 20,000 Hz and have five channels that include right front, left front, center, right rear and left rear.