Career
As a non degree-holding "consultant",[5] Dolby played a key role in the effort that led Ampex to unveil their prototype Quadruplex videotape recorder in April 1956 which soon entered production.[5]
After Cambridge, Dolby acted as a technical advisor to the United Nations in India until 1965, when he returned to England, where he founded Dolby Laboratories in London with a staff of four. In that same year, 1965, he invented the Dolby noise-reduction system, a form of audio signal processing for analog tape recorders. His first U.S. patent application was made in 1969, four years later. The system was first used by Decca Records in the UK.[9]
The Dolby B consumer noise-reduction system works by compressing (boosting) low-level high-frequency sounds during recording and expanding (decreasing) them symmetrically during playback, which also decreases inherent tape noise. This reduces the audible level of tape hiss.[9] The professional Type A system operates on four different frequency bands, and the final SR system on ten.
After his pioneering work with audiotape noise reduction, Dolby sought to improve film sound. As Dolby Laboratories' corporate history explains:
The first film with Dolby sound was A Clockwork Orange (1971), which used Dolby noise reduction on all pre-mixes and masters, but a conventional optical sound track on release prints. Callan (1974) was the first film with a Dolby-encoded optical soundtrack. The first true LCRS (Left-Center-Right-Surround) soundtrack was encoded on the movie A Star Is Born in 1976. In less than ten years, 6,000 cinemas worldwide were equipped to use Dolby Stereo sound.
Dolby then developed a digital surround sound compression scheme for the cinema. Dolby Stereo Digital (now simply called Dolby Digital) was first featured on the 1992 film Batman Returns. Dolby Digital is now found in the HDTV (ATSC) standard of the United States, DVD players, and many satellite-TV and cable-TV receivers.[10][11]
Dolby was a Fellow and past president of the Audio Engineering Society.[12]
- Upon investigation, Dolby found that many of the limitations in optical sound stemmed directly from its significantly high background noise. To filter this noise, the high-frequency response of theatre playback systems was deliberately curtailed… To make matters worse, to increase dialogue intelligibility over such systems, sound mixers were recording soundtracks with so much high-frequency pre-emphasis that high distortion resulted.
