What do the Westbury Theater in Huntsville, Alabama, the Plaza Theater in Owensboro,
Kentucky, the Radio City Music Hall in New York, the Europa Theatre in Duesseldorf,
the Yurakuza Theater in Tokyo, and the Empire Theatre in London all have in
common? Their marquees are emblazoned with the legend "Dolby Stereo," proudly
proclaiming their ability to show films with this new kind of motion picture
sound. In more than 1,800 theaters in the United States and around the world,
theater owners have learned that being equipped to show films with Dolby stereo
sound is a definite "plus" in attracting movie fans.
Part of this attraction is undoubtedly due to the movie patrons' familiarity with the Dolby name, as exemplified in the cassette recorders incorporating Dolby B noise reduction they use in their homes and in the Dolby B prerecorded cassettes they play back on these machines.
With more than 100 licensing agreements with companies throughout the world, who manufacture more than 650 different Dolby B-Type products, ubiquitous is the word for Dolby. Indeed, the name Dolby in its various audio processing and equipment embodiments has nearly become a generic part of the language. It is also interesting to note that this not inconsiderable Dolby "industry," that now encompasses many aspects of the audio, motion picture and television business, all began with a young engineer's basic dislike of the tape hiss produced by magnetic tape recorders. That young engineer, of course, was Dr. Ray Dolby, who at that time was living in London. Dr. Dolby's development of his A301 Noise Reduction System has been well documented in the audio press, and I am sure most readers are familiar with its gene sis.
As I write this, I have just returned from a week-long visit to London, where I had the pleasure of a chat with Arthur Haddy, the brilliant engineer who guided the technical destinies of Decca Records for 52 years. As a friend of 25 years standing, I was saddened by the circumstances that resulted in the recent sale of Decca to Polygram, the death of Decca's founder, Sir Edward Lewis, and the subsequent retirement of Arthur Haddy. It was Haddy, the "father" of Decca ffrr recording, who recognized the value of Ray Dolby's A301 Noise Reduction System and after extensive tests ordered nine of the systems in November, 1965. In November of 1966, Decca issued the first recording made with the Dolby A system, Mahler's 2nd Symphony conducted by Georg Solti.
Now, 14 years later, as Arthur and I were chatting, he told me that the Decca recording team (Jim Lock et al., kept intact by Polygram) were in Chicago making a digital recording of ... Mahler's 2nd Symphony with Sir Georg Solti conducting the Chicago Symphony Orchestra.
End of one era, and the beginning of another? In a symbolic sense, yes. If digital recording becomes the universal standard for master recording, then ultimately it would make obsolete all forms of tape noise reduction ... Dolby, dbx, Telcom or whatever. However, even if we assume the audio consumer finally has access to true digital playback systems, it will take years be fore an adequate library of digital recordings of the "basic" classical repertoire is available.
Meanwhile, the average music lover will continue to use analog stereo discs and Dolby B prerecorded cassettes. In the case of this new digital recording of Mahler's 2nd Sym phony, it will be used to produce an analog stereo disc recording and ultimately a digital disc--but it will also be used to produce a prerecorded cassette with Dolby B noise reduction.
While Ray Dolby is keeping a close eye on digital developments and is quite aware of their implications, he uses this information to expand his business in logical directions. Hence, his deep involvement in Dolby processing and equipment manufacturing for motion picture sound and his latest development for consumer audio, the Dolby "HX" headroom extension system.
Dolby Headquarters I have known Ray Dolby since 1968-before the B-Type noise reduction system came into being. Even back then, I had been involved in tape recording for nearly 20 years and had also developed an abiding hatred of tape hiss. When I heard about the Dolby A noise-reduction system, and subsequently found how effectively it dealt with the pernicious malady of tape hiss, I became an immediate and enthusiastic booster of the system.
Since then, I have visited Ray and his charming wife Dagmar at their London headquarters on a number of occasions and have had the pleasure of having them as guests in my home on Long Island. In January of 1976, the Dolbys took up residence in San Francisco and opened a new headquarters office in that city. The San Francisco operation encompasses administration, research and development, new market development, international licensing, and United States sales. The London factory and offices continue to manufacture all Dolby professional equipment and handle international sales of same. Some months ago, Ray Dolby invited me to the new San Francisco headquarters, and I can tell you it was a rewarding experience.
In the Dolby building in downtown San Francisco, the two points of interest for me were the research and development lab, presided over by David Robinson, VP for Engineering and long-time associate of Ray Dolby, and a most elaborately equipped "mini-theater" projection room. As you might expect, the R&D lab is replete with the cool green color of precision Bruel and Kjaer oscillators and graphic recorders, spectrum analyzers, etc. as well as the precision 'scopes and lab exotica from other manufacturers.
These days, David Robinson is kept busy with new developments in noise reduction for motion picture sound, as exemplified by the new CP200 Cinema Processor, an elaborate unit capable of reproduction of any of the Dolby en coded mono or stereo, optical or magnetic sound tracks. Of late, there has been new emphasis on Dolby noise-reduction equipment for video-tape recorders. For example, the Dolby NRU-10 is an outboard A-Type two-channel audio noise-reduction system for professional video-tape recorders, providing 10 dB of noise reduction from 20 Hz upwards, and rising to 15 dB at 9 kHz and above. Then there is the Dolby Catalog No. 155, a two-channel audio noise-reduction unit with specifications similar to the NRU 10; the 155 is specifically designed to be incorporated in the Sony BVH-1000 video-tape recorder.
As you are probably aware, for some time now Japan has been broadcasting TV programs with stereo sound, and in fact there are TV sets on the Japanese market incorporating stereo audio systems. You may also know that a proposal to provide stereo audio for TV broadcasts in this country is now be fore the FCC. The general opinion is that action favorable to this proposal will be forthcoming within two years.
Noise Reduction in VCRs
Obviously, with TV stereo audio al ready being broadcast in Japan, those consumers who want to make home video recordings with the stereo sound will need new models of the video cassette recorders incorporating stereo audio facilities. Furthermore, it is expected that many will want to play back these stereo recordings over their higher quality stereo component systems, rather than through the speakers in their TV sets. Since the VCR machines have narrow-track audio channels and operate at even slower speeds than an audio cassette, in order to avoid unacceptably noisy sound with higher levels of distortion, the new VHS two-channel video recorders will be equipped with Dolby B-Type noise reduction. Thus far, such VHS VCR manufacturers as JVC, Matsushita, Hitachi, Akai, Sharp, and Mitsubishi have agreed to incorporate Dolby noise reduction in their new stereo VCRs.
If I were a Texas oil baron, one of the things I would want in my home is a projection room just like the one at Dolby Laboratories in San Francisco.
Here is a purpose-built room approximately 25 feet wide by 35 feet deep with 9-foot ceilings. It is acoustically treated for maximum intelligibility of dialogue and high-quality music sound. There is a wide-aspect-ratio projection screen, and in the projection booth are two modern, professional 35-mm projectors equipped for the showing of Dolby mono and stereo optical prints and a 70-mm projector with magnetic head for six-channel "surround" stereo playback of films like "Apocalypse Now." Needless to say, the room is equipped with a generous number of very comfortable seats. Ray Dolby treated me to one of the most stunning audio-visual experiences I have ever had. A demonstration film of excerpts from a number of productions was shown, and while the first two clips were interesting, the third clip from the picture "Days of Heaven" was simply mind-blowing.
Now the speaker layout in this projection room has five speakers up-front behind the wide screen and a number of small, high-Q speakers mounted above the heads of the audience and disposed in a "string" starting about halfway back on each side of the room and continuing around to the back of the room. There may be as many as 14 small speakers mounted on each side and rear in this configuration. In this setup tracks 1, 3 and 5 are respectively left, center, and right screen. Speakers 2 and 4 carry bass-enhancement information below 100 Hz, which is combined with non-directional bass from track 6 and subsequently can be fed to subwoofers for ultra-low frequency effects. Mid- and high-frequency stereo surround information, which has been phase matrixed into tracks 2 and 4, is fed to the left and right, side and rear "strings" of speakers respectively.
The key scene in "Days of Heaven" shows some farmers surveying a sea of lush, golden wheat somewhere in the Midwest about the turn of the century, when to their horror, the wheat fields are attacked by a plague of locusts.
While the farmers are frantically beating at the voracious insects, an old fashioned steam tractor comes on the scene, somehow catches on fire, and the driver jumps for his life. The tractor, now an out-of-control juggernaut, careens through the wheat fields, which sets the wheat ablaze. Well ...
between the speakers up-front and all the surround speakers, the whir and buzz of countless billions of locusts is chillingly real. Then, add to this the cries of the farmers, the clanking and snorting sounds of the steam tractor, and the crackle and pervasive low-frequency roar of the fire. The brilliance and clarity of the projection, the purity of the color, and the startling realism of all the sonic elements combine into an emotional experience of tremendous impact. If all motion pictures could be presented to the public with such outstandingly good audio and visual quality, the movie houses would be packed to the rafters!
HX-ing Bias and EQ
On the consumer audio front, Dolby is concentrating on the HX headroom extension system. This system has been described in these pages before, but evidently quite a few people have the wrong impression about what it does. For example, some people think it is a new type of Dolby noise-reduction system. Rather, it is a rather clever adjunct to existing B-Type Dolby noise reduction, which through use of the control signal in the B-Type circuitry allows varying record bias and record equalization on a dynamic basis. This permits dramatically increased head room in recording the very short wavelengths of high-level, high-frequency signals, and thus avoids tape saturation. The increase in high-frequency headroom can be as much as 10 dB above 10 kHz. With an increasing number of audiophiles recording their direct-cut and hybrid digital/analog discs to cassettes, the increased high-level, high-frequency energy on these discs has been causing severe problems with tape saturation. Many rock and pop albums, which make liberal use of electronic synthesizers, are nightmares to record cleanly because, unlike conventional musical instruments which have relatively low levels of high-frequency overtones, a synthesizer can easily produce a 15-kHz signal at very high level.... One of the most intriguing aspects of the Dolby HX system is that cassettes recorded with it can be played back on any cassette deck equipped with Dolby B noise reduction. In other words, there is no special HX playback circuitry involved. This naturally gives rise to the thought that one of these days we may have ultra-high-quality prerecorded cassettes using chromium dioxide or even metal-particle tape, which have been recorded with Dolby B-Type noise reduction and the HX headroom extension system. On the better cassette decks, this should enable music to be reproduced with a dynamic range of better than 70 dB! I'm sure even Ray Dolby didn't envision this kind of performance from a tiny cassette operating at 1 7/8 ips when he in vented his noise-reduction system.
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(Source: Audio magazine, Jul. 1980; Bert Whyte)
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