A group of systems designed to reduce noise in analog sound recordings. Dolby A, B, C, and SR are each encode/decode systems which are incompatible with each other. Each has been incorporated into video recording systems.
AKA: Dolby, Dolby Labs, Dolby Digital, Dolby SR, Dolby 70mm, Dolby Stereo Dolby Laboratories, Inc has produced a number of noise reduction and sound enhancement processes. Competitors include DTS and SDDS.
The signal processing system that reduces the inherent noise in recording media without affecting the sound. Dolby A-type and, subsequently, Dolby SR were originally used on commercial music recordings and later on film soundtracks. Dolby B-type, C-type, and S-type were designed for the consumer audio cassette.
A patented noise reduction system that increases dynamic range and signal-to-noise ratio of Dolby encoded media.
A patented noise reduction technique from Dolby Labs that raises the volume of sound track elements most likely to be affected by inherent noise during recording and then lowers them again during playback so that the noise seems lower in relation to the wanted elements of the audio recording.
A proprietary form of reducing noise and hiss found in the cassette medium.
A noise-attenuating system that makes use of complementary compression and expansion techniques over specific frequency bands to reduce background noise in analog tape systems. Dolby A and SR are wide-band systems for professional use. Dolby B offers about 10 dB of noise attenuation above 4 kHz. Dolby C works above 1 kHz and increases the attenuation to about 20 dB. Dolby S gives about 24 dB of noise reduction.
Decodes Dolby-encoded cassette tapes during playback to virtually eliminate the tape hiss which is especially apparent in quiet environments. Dolby B is the most widely used system. Dolby C is an extension that is even more effective at increasing the signal-to-noise ratio.