The Cheshire innovation

By Harold D. Wallace Jr.
Musical device with Dolby system
"'I wish you wouldn't keep appearing and vanishing so suddenly: you make one quite giddy.'

"'All right,' said the Cat; and this time it vanished quite slowly, beginning with the end of the tail, and ending with the grin, which remained some time after the rest of it had gone.

"'Well! I've often seen a cat without a grin,' thought Alice, 'but a grin without a cat! It's the most curious thing I ever saw in all my life.'"

- Lewis Carroll, Alice in Wonderland (Book-of-the-Month Club Inc., 1994; originally published 1865), 88-89.

People have become used to technologies that seemingly disappear. Devices whose presence so fades into the background of our daily lives that we use them without thought, noticing them only when they fail. Despite that, when those devices demand our attention, typically there's still something to see—a burned-out light bulb or a dead cell phone.

We recently received a donation of materials related to the work of inventor Ray M. Dolby (1933-2013). Dolby Laboratories, the company Ray founded, is celebrating its Golden Anniversary so we decided this would be a good time to bring examples of Ray's work into the national collections. The influence of Dolby's contributions to sound engineering is of unquestioned significance and we had very few pieces to document the history of that technology.

While many people have heard the Dolby name and seen it on their radio or video devices, for most consumers there's little else to see of Ray's work. As I reviewed the history and considered what we might collect, I realized that, like the Cheshire Cat, the technology invented by Dolby and his company slowly vanished into tape decks, radios, televisions, and studio sound systems, leaving behind not a grin but a logo.

Ray Dolby's earliest commercial work came as a nineteen-year-old member of the Ampex team that developed the VR-1000, the first commercially successful video recorder. Ray helped design the recording head for the 1956 studio device and we have the first production unit in the collections. However, Ray's signature achievement was the invention of the sound compander. This device reduced the extra noise that recording and reproducing equipment added to sound recordings.

Six men with machine

Unwanted noise introduced by the equipment degrades sound recordings' quality. The crackle made by a stylus moving in a groove, the hiss of tape passing over a magnetic head, electrical effects that distort a signal—these all make recordings less accurate than the original sounds. Inventors have striven for better sound quality or "high fidelity" ever since Thomas Edison introduced his phonograph in 1876. Ray Dolby devised a way to reduce unwanted noise by compressing and then expanding the audio signal. Hence the term, sound companding. Ray's compander dramatically improved the quality of sound recordings. He and his company have spent the last fifty years building on that work.

Ray's early noise reduction systems, like this prototype model 301 from 1966, were by no means invisible. Dolby intended the model 301 to be a commercial-grade product for professional sound studios and designed the unit in his London laboratory. Dolby referred to this as his type A system.

Dolby 301 unit

In 1967, Dolby made a deal with Henry Kloss (1929-2002), another audio inventor and a maker of Advent tape recorders for the consumer market. This Dolby type B noise reduction unit was designed to work with Kloss' recorders, although this unit was for playback use only. The now familiar double-D logo appears in the upper left corner.

Dolby type B

The 1968 model 100, a rack-mounted unit worked in both record and playback modes. An electrical schematic on the bottom of this piece is an especially nice feature from a museum standpoint since it helps document exactly how the device was used. A note indicating that this device was "not licensed for use in the mass production of recordings" indicates Dolby's intended market for this unit: consumers, not studios.

Dolby model 100

By the early 1970s, Dolby's technology moved from being an add-on accessory to an integral part of the Advent recorder. This model 201 cassette deck features a switch to activate the noise reduction system. Aside from the switch, only the logo shows the presence of Ray's invention. The recorder also included a switch that allowed the use of chromium oxide tapes. The CrO2 tapes gave superior performance than ordinary ferrite oxide tapes but the sound properties could change over time. The switch helped the Dolby system compensate.

Cassette deck

During the 1980s and 1990s, users no longer needed to throw a switch. Dolby's noise reduction system simply turned-on with the device. Ray and his company adapted the technology for new audio media and continued to design circuits for both consumer and professional markets. This Type S system board from 1989 shows how Dolby's technology continued to shrink and be integrated at the component level.

Dolby type S board

Today, like the Cheshire Cat in his tree, Dolby's noise reduction system sits invisibly within users' audio equipment. Only the logo remains to mark its presence. The first rule here is "you can't collect it all," so curators weigh many factors when considering what to collect. I wanted to document the history of Ray and his company while also considering how we might present that history to our audiences, a difficult task with black box inventions. We already had several objects with little for visitors to see except the logo. By selecting these pieces, I can show how Ray's technology morphed from a large, discrete component into something that most users never even know is there. As Alice might say, a curious thing indeed.

Harold Wallace, curator in the Division of Work and Industry, has also blogged about an 1883 electrical disaster and a Korean War telegraph.

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