If you are new to the world of home cinema you may well have heard the words ‘5.1’, ‘Dolby Digital’ or ‘DTS’ frequently mentioned. Put simply, they are both multi channel digital sound formats that are used to bring the full benefit of digital surround sound to your home cinema (and indeed to real cinemas).
They both typically consist of 6 channels of sound and to confuse matters are more commonly known as ‘5.1’ surround sound. The channels are split into with two front channels, 2 rear channels, a centre channel for speech, and the .1 part for the low frequency subwoofer sounds.
Widely supported
Most DVDs will support a digital sound format of some description, even when the film is quite old. In this case the original sound tape will be remastered and ‘cleaned up’ to remove hiss and drop-outs and re-recorded in a digital sound format. For bigger re-releases, the sound is often completely re-mastered into a surround sound track even when it was not originally available.
Nearly all DVD players we’ve ever come across have supported at least Dolby Digital with most also supporting DTS. This means that either your DVD player can decode the sound ready to send to your home cinema system, or you can output the raw un-decoded sound and let your home cinema amplifier do they work if you have one.
Although each format has various specialist sub types, the two main formats are:
- Dolby Digital®
Sometimes also known as ‘AC-3’, Dolby Digital is developed by Dolby Laboratories, Inc and is by far the most widespread of the digital sound formats with most DVD’s offering some sort of Dolby Digital sound format on the discs. Sometimes when a surround sound format is not available, especially on older films, the sound is cleaned up as converted to 2 channel audio known as Dolby Digital Stereo (or 2.0). - DTS (formerly known as Digital Theater Systems)
DTS is less common, but arguably more sought after as it is generally considered to offer a better quality of sound. This is mainly because the sound has not been compressed as much so the ‘bit rate’ is higher. This does often have the downside that single disc DVDs with DTS tracks will not have as many extras, but more often than not, the extras will appear on a separate disc so there will be no overall loss.
For newer high-definition Blu-ray discs, there are two enhanced high-definition sound formats from these two laboratories, known as DTS-HD Master and Dolby Digital TrueHD. Read our page on high-definition sound formats for more information.
Dolby Digital is a registered trademark of Dolby Laboratories, Inc.