R. Dolby is an electrical engineer from Stanford. He established Dolby Laboratories in England in 1965. He had recorded for two years Indian classical and folk music as a UNO representative in Punjab and UP. He developed Dolby Noise Reduction system in those days. Dolby Lab introduced Dolby Stereo of four sources which was used in A Star is Born. This system invited attention of all when it was used in Star Wars ( 1977 ). First, there was monophonic speaker behind the screen. Thereafter, in stereo system the sources were Left, Centre, Right and Surround (LCRS ). The sound was more realistic. Dolby SR was introduced in 1986. SR stands for spectral recording. Dolby Digital or Dolby 5.1 with six tracks was introduced in 1991. Here there are tracks for left, centre, right and left surround ( LS ) and right surround ( RS ). There is also a low frequency effects ( LFE ) or sub-woofer track. It emits low frequency sounds such as bomb explosions, thunder and earth quakes. It adds to the effect. 5.1 or 7.1 means five or 7 tracks with an additional 0.1 or sub-woofer track. Batman Returns ( 1992 ) was the first movie to use Dolby Digital. DTS and Sony also introduced 5.1, but Doby dominated. In 1999, Dolby introduced Dolby Ex ( 7.1 ) and in 2012 Dolby Atomos ( 7.1.4 ). In Atomos, there are speakers over the heads of the viewers. 7.1.4 means seven tracks with 0.1 subwoofer and 0.4 overhead source. It gives three-dimensional effect. In Atomos, you feel as if the rain is falling right on your head. Many theatres in India now use Dolby sound system.