Created by Dolby Laboratories, Dolby Digital was first used in movie theaters, as theaters at the time was the only place you can hear surround sound. However, when the technology to create surround sound became available at home, many electronic hardware corporations such as Sony, Panasonic, and many others created stereo receivers that carried the capability to produce Dolby surround sound. You needed to get a number of additional speakers specially created to take advantage of the technology. However, at the time, there wasn't many media sources that took advantage of this sound feature. This changed when DVD's replaced VHS Tapes as the new standard of home video playback. Because DVD's are capable of carrying lots of information in a single disc, many movie studios and other digital media developers were able to include the codec capable of using surround sound.
As the popularity of digital media grew, so did the use of Dolby Digital. When cable television went digital, most of the channels were updated to using Dolby Digital, this was especially the case with premium channels that showed movies like HBO and Showtime. Sports broadcast also were updated to take advantage of Dolby surround sound. When video game consoles and PC games using DVD-Media became available, many of the games included the option to use Dolby surround sound.
Today Dolby Digital is included in most digital media, and almost every hardware source has the capability to use it. There are even headphones you can buy that have a Dolby Digital sound set up, as well as cell phones and many other compact technologies.
Over the years, Dolby Laboratories have updated their sound technology to produce the most realistic surround sound possible.
Uses six speakers for surround sound. It's known today as 5.1 sound. These include:
- Front Left - Right Speakers
- Rear Left - Right Surround Sound Speakers
- Center Front Speaker
- Subwoofer Speaker (for .1)
DOLBY DIGITAL EX
Is an update to the 5.1 surround sound format. It adds an additional sound codec called matrix technology. This clones channels which comes from the rear surround sound speakers. It's known today as 6.1 or 7.1 sound.
DOLBY DIGITAL SURROUND EX
Is an update to the EX surround sound format. Digital Laboratories teamed up with THX to produce a new cinematic sound field used along with the 5.1, 6.1, and 7.1 formats allowing for better surround sound production. First used in the movie Star Wars - Phantom Menace.
DOLBY DIGITAL LIVE
Is technology mainly used for console video games and PC video games. It can convert any video game sound signal into a 5.1 signal.
DOLBY DIGITAL PLUS
Plus allows you to hear 5.1 sound at a higher bit rate than the standard Dolby Digital bit rate. It also clears up a lot of artifacts for more accurate sound production. It was mainly used in the now abandoned HD-DVD discs. A lot of Blu-Ray discs, however, have the option to use this format.
DOLBY TRUE HD
Is the most advanced version of Dolby Digital used today. It was created to take full advantage of the new High Definition technology. The codec is capable of producing lossless sound quality, while the other versions had sound limitations. True HD is currently used on many Blu-Ray discs.