Ambisonic Surround Sound FAQ, version 2.8: Section 15

15. Can Ambisonics reproduce DTS Digital Surround?

Ambisonics cannot contribute to the DTS Digital Surround encoding or decoding processes; it can make contributions before the 5.1 discrete channels are encoded and after they are decoded.

DTS Digital Surround is a method of compressing and encoding 5.1 discrete audio channels to make them suitable for transmission using CD, Laserdisc, DAT or DVD. More details are available on the DTS Digital Surround Web page.

The 5.1 channels have complete separation but, sadly, this is not sufficient for realistic surround sound reproduction. Channel separation only permits sounds to be reproduced from the direction of a speaker. To reproduce sounds from between speakers requires a mixing style, and the most popular stereo mixing style, pair-wise mixing, simply does not work in surround sound.

DTS Digital Surround was originally designed to enhance the enjoyment of motion pictures. The limitations of pair-wise mixing are not a serious impediment to this, however, they do make pair-wise mixed DTS Digital Surround unsuitable for music.

One solution is for sound engineers to use a mixing style other than pair-wise mixing to mix the 5.1 discrete channels. Happily, an alternative exists - Ambisonics.

Another poorer solution is for the 5.1 pair-wise mixed channels to be converted into W, X, Y and additional signals, and to then use Ambisonic technology to reproduce the sound field. This is described in the Gerzon 1992b reference.

Pair-wise mixed DTS Digital Surround is only impressive; Ambisonics is accurate and can be impressive or subtle as required.