Dolby Noise-reduction System - Dolby S

Dolby S

Dolby S was presented in 1989. It is found on some Hi-Fi and semi-professional recording equipment. It was intended that Dolby S would become standard on commercial prerecorded musicassettes in much the same way that Dolby B had in the 1970s, but this never happened, as Dolby S came to market at a time when the Compact Cassette was being replaced by the Compact Disc as the dominant mass market music format. Dolby Labs claimed that most members of the general public couldn't differentiate between the sound of a CD and a Dolby S encoded cassette. Subsequently, Dolby S appeared only on high-end audio equipment.

Dolby S is much more resistant to playback problems caused by noise from the tape transport mechanism than Dolby C. Likewise, Dolby S was also claimed to have playback compatibility with Dolby B in that a Dolby S recording could played back on older Dolby B equipment with some benefit being realized. It is basically a cut down version of Dolby SR and uses many of the same noise reduction techniques. Dolby S is capable of 10 dB of noise reduction at low frequencies and up to 24 dB of noise reduction at high frequencies.