Dolby E

Dolby E is an audio encoding and decoding technology that allows up to 8 channels of audio to be compressed into a digital stream that can be stored on a standard stereo pair of audio tracks.

Anything up to a 5.1 mix can be recorded in 16-bit, however, if anything more than 5.1 is required, the tape format must accept 20-bit audio.

It is very important to ensure that a Dolby E stream is never played through monitors without being decoded. The data stream produces a very loud digital noise that can easily blow the tweeters. Tape labelling is essential to avoid this.

Dolby E never reaches home viewers, it is used when passing material between different production facilities etc. and then re-encoded into a more suitable format before being broadcast.