Dolby SVA provided a method for putting high-quality stereo soundtracks on optical sound prints.

The first film to use Dolby noise reduction throughout the production process is A Clockwork Orange (1971), though much of the benefit was lost when it was released with a standard "Academy" optical soundtrack.

This led to a proposal from Dolby that A type noise reduction be applied to the optical soundtrack on release prints.

It involved a drastic roll-off in the high-frequency response of the theater system with the intention of reducing the audibility of noise and distortion.

The idea of putting a two-channel optical stereo soundtrack in the normal soundtrack area of a film print was not new; the stereo pioneer Alan Blumlein had made experimental stereophonic films using such a system as early as 1933, and J. G. Frayne of Westrex had proposed a similar system to the SMPTE in 1955.

[8] By 1970, however, it was apparent that magnetic recording methods were not going to displace optical soundtracks on most release prints, and in the early 1970s Eastman Kodak revived the idea, as described by R. E. Uhlig in a paper presented to the SMPTE in 1972.

[7] The remaining problem was the lack of a center channel, regarded as essential to lock dialogue to the middle of the screen.

[10] He considered the possibility of splitting the soundtrack area three ways to provide a third center channel, but dismissed it because of the negative impact it would have on dynamic range and the problems involved in converting film projectors.

Instead he suggested feeding a center-channel speaker with a simple mix of the left and right channels; however, this is not entirely satisfactory as it degrades the stereo separation.

But the success of 1977's Star Wars, which used the 4-channel system to great effect, encouraged owners of smaller theaters to install stereo equipment for the first time.

[11] In addition to the logic circuitry the surround channel is also fed via a delay, adjustable up to 100 ms to suit auditoria of differing sizes, to ensure that any leakage of program material intended for left or right speakers into the surround channel is always heard first from the intended speaker.

Some domestic listeners were keen to hear these soundtracks in a manner more akin to how they would have sounded in the theater and for that market some manufacturers produced simplified surround decoders.

Dolby did not approve of this later practice, which results in loss of separation, but instead used these channels for LFE (low-frequency effects) utilizing the bass units of the otherwise redundant intermediate front speakers.

Its cinema processor introduced improvements in matrix decoding and convolution matching with greater channel separation.

An included balancing circuit compensated for film weave and some imbalances between the left and right tracks that previously caused voice leakage into the surround channel.

The Ultra Stereo sound system won a 1984 Technical Achievement Award from the Academy of Motion Picture Arts and Sciences.