In 1971, Stanley Kubrick's A Clockwork Orange was released.  It was the first movie to use Dolby noise-reduction on all magnetic generations up to the magnetic print master. The final release, however, was academy mono.

In 1972, Dolby's X-curve EQ standard for theaters and mix rooms was formalized by the International Standards Organization (ISO 2969) to replacethe Academy curve of the 1930's.  Using pink noise, the X-curve specifies a 3 dB per octave roll-off above 2 kHz.  That same year A Quiet Revolution premiered, which was the first film to have Dolby A noise reduction on the release print.  The movie had been made to show the advantages of noise reduction to exhibators.

In 1974, Eastman Kodak, RCA, and Dolby released an optical, stereo variable soundtrack (SVA).  This was made possible because of Dolby A noise reduction.  Before the advent of this noise reduction, it was too noisy to have two optical channels on a piece of 35mm film.  They demonstrated a reel of Stardust  that was remixed for the new technology at a 1974 Society of Motion Picture and Television Engineers meeting.  That same year The Little Prince was released with 35mm magnetic release prints with Dolby A noise reduction.  The only other releases in this format included The Song Remains the Same and Nashville.

Later that year Sensuround, a system developed by W. O. Watson and Richard Stumpf at Universal Pictures, was released.  This format injected tones from 5 - 40 Hz at 110 - 120 dBbased on control track information on the film.  Sensurround Some Sensurround movies included Earthquake!, Midway, Battlestar Galactica, and Rollercoaster.

In 1976, A Star Is Born became the first Dolby Stereo film.  Dolby Stereo was a 4-channel format phase matrixed into a two channel format.  This was a sensible solution because it allows the four channels to be encoded into any stereo format including FM radio, record, tape, CD, etc.  The format uses a left, center, right, surround speaker array and was first utilized by the stereo variable area soundtrack.  The two encoded channels are known as the Left total (Lt) and Right total (Rt).  Everything mixed to the left channel is heard on the left and everything mixed on the right will be heard on the right.  The center information is taken from everything that is in both channels and 3 dB down.  The surround information is recorded down 3 dB on both Lt and Rt channels so that one channels is plus 90 degrees and the other is minus 90 degrees.  Dolby used the matrixed surround format to avoid the pitfalls of having four optical tracks on the film.  In addition to the added noise there were problems with mis-alignment due to very narrow gaps between the tracks.  The narrowness of the gap makes alignment more critical.

In 1977, Star Wars, revolutionized film sound with Ben Burtt's award winning sound effects.  This same year, Dolby unveilled the 70mm "Baby Boom" format.  Baby boom used the same 70mm format as Todd-AO with some slight modifications.  There were three speakers behind the screen designated left, center, and right.  There was also one surround channel and two low frequency effects channels that excepted frequencies below 200 Hz.  Dolby relized with the release of both Star Wars and Close Encounters of the Third Kind how important thaving a separate low frequency effects channel was.

In 1979, with Apocalypse Now, Dolby debuted the Dolby 70mm "Split Surround" format.  Like the Baby Boom format, Split Surround is based on the Todd-AO format.  It was actually the first 5.1 format as we think of it today.  It had a left, center, and right, left surround, right surround, and low frequency effects channel.  Like the genius behind other Dolby products, Split Surround wass backwards compatable to previous formats.  In this case, Split Surround was compatable with the Baby Boom format.  Like Baby Boom, Split Surround had the same left, center, right, mono surround, and two boom tracks.  The added left and right surrounds were put on the same tracks as the two boom tracks.  This was accomplished by limiting the boom tracks to under 200 Hz and the left and right surrounds were limited to about 500 Hz.  If a theater was set up for the Baby Boom format the mono surround would be used and the split surround information on tracks 2 and 4 would be ignored.  In a Split Surround theater, the mono surround would be ignored and the left and right surrounds would be employed.  Other Split Surround channels included Superman II, Pink Floyd:  The Wall, and The Jazz Singer (1980).  With Apocalypse Now, Walter Murch coined the title "Sound Designer".

 Created by Jonathan Kay, Kimber Ghent, Brian Chumney, and Erik Lutkins

Return to MTSU SMPTE Home