Compact disc

Compact disc
The invention: A plastic disk on which digitized music or computer
data is stored.
The people behind the invention:
Akio Morita (1921- ), a Japanese physicist and engineer
who was a cofounder of Sony
Wisse Dekker (1924- ), a Dutch businessman who led the
Philips company
W. R. Bennett (1904-1983), an American engineer who was a
pioneer in digital communications and who played an
important part in the Bell Laboratories research program
Digital Recording
The digital system of sound recording, like the analog methods
that preceded it, was developed by the telephone companies to improve
the quality and speed of telephone transmissions. The system
of electrical recording introduced by Bell Laboratories in the 1920s
was part of this effort. Even Edison’s famous invention of the phonograph
in 1877 was originally conceived as an accompaniment to
the telephone. Although developed within the framework of telephone
communications, these innovations found wide applications
in the entertainment industry.
The basis of the digital recording system was a technique of sampling
the electrical waveforms of sound called PCM, or pulse code
modulation. PCM measures the characteristics of these waves and
converts them into numbers. This technique was developed at Bell
Laboratories in the 1930’s to transmit speech. At the end of World
War II, engineers of the Bell System began to adaptPCMtechnology
for ordinary telephone communications.
The problem of turning sound waves into numbers was that of
finding a method that could quickly and reliably manipulate millions
of them. The answer to this problem was found in electronic computers,
which used binary code to handle millions of computations in a
few seconds. The rapid advance of computer technology and the semiconductor circuits that gave computers the power to handle
complex calculations provided the means to bring digital sound technology
into commercial use. In the 1960’s, digital transmission and
switching systems were introduced to the telephone network.
Pulse coded modulation of audio signals into digital code achieved
standards of reproduction that exceeded even the best analog system,
creating an enormous dynamic range of sounds with no distortion
or background noise. The importance of digital recording went
beyond the transmission of sound because it could be applied to all
types of magnetic recording in which the source signal is transformed
into an electric current. There were numerous commercial
applications for such a system, and several companies began to explore
the possibilities of digital recording in the 1970’s.
Researchers at the Sony, Matsushita, and Mitsubishi electronics
companies in Japan produced experimental digital recording systems.
Each developed its own PCM processor, an integrated circuit
that changes audio signals into digital code. It does not continuously
transform sound but instead samples it by analyzing thousands
of minute slices of it per second. Sony’s PCM-F1 was the first
analog-to-digital conversion chip to be produced. This gave Sony a
lead in the research into and development of digital recording.
All three companies had strong interests in both audio and video
electronics equipment and saw digital recording as a key technology
because it could deal with both types of information simultaneously.
They devised recorders for use in their manufacturing operations.
After using PCM techniques to turn sound into digital code, they recorded
this information onto tape, using not magnetic audio tape but
the more advanced video tape, which could handle much more information.
The experiments with digital recording occurred simultaneously
with the accelerated development of video recording technology
and owed much to the enhanced capabilities of video recorders.
At this time, videocassette recorders were being developed in
several corporate laboratories in Japan and Europe. The Sony Corporation
was one of the companies developing video recorders at this
time. Its U-matic machines were successfully used to record digitally.
In 1972, the Nippon Columbia Company began to make its master recordings
digitally on an Ampex video recording machine.
Links Among New Technologies
There were powerful links between the new sound recording
systems and the emerging technologies of storing and retrieving
video images. The television had proved to be the most widely used
and profitable electronic product of the 1950’s, but with the market
for color television saturated by the end of the 1960’s, manufacturers
had to look for a replacement product.Amachine to save and replay
television images was seen as the ideal companion to the family
TV set. The great consumer electronics companies—General
Electric and RCAin the United States, Philips and Telefunken in Europe,
and Sony and Matsushita in Japan—began experimental programs
to find a way to save video images.
RCA’s experimental teams took the lead in developing an optical
videodisc system, called Selectavision, that used an electronic stylus
to read changes in capacitance on the disc. The greatest challenge to
them came from the Philips company of Holland. Its optical videodisc
used a laser beam to read information on a revolving disc, in
which a layer of plastic contained coded information. With the aid
of the engineering department of the Deutsche Grammophon record
company, Philips had an experimental laser disc in hand by
1964.
The Philips Laservision videodisc was not a commercial success,
but it carried forward an important idea. The research and engineering
work carried out in the laboratories at Eindhoven in Holland
proved that the laser reader could do the job. More important,
Philips engineers had found that this fragile device could be mass
produced as a cheap and reliable component of a commercial product.
The laser optical decoder was applied to reading the binary
codes of digital sound. By the end of the 1970’s, Philips engineers
had produced a working system.
Ten years of experimental work on the Laservision system proved
to be a valuable investment for the Philips corporation. Around
1979, it started to work on a digital audio disc (DAD) playback system.
This involved more than the basic idea of converting the output
of the PCM conversion chip onto a disc. The lines of pits on the
compact disc carry a great amount of information: the left- and
right-hand tracks of the stereo system are identified, and a sequence of pits also controls the motor speed and corrects any error in the laser
reading of the binary codes.
This research was carried out jointly with the Sony Corporation
of Japan, which had produced a superior method of encoding digital
sound with its PCM chips. The binary codes that carried the information
were manipulated by Sony’s sixteen-bit microprocessor.
Its PCM chip for analog-to-digital conversion was also employed.
Together, Philips and Sony produced a commercial digital playback
record that they named the compact disc. The name is significant, as
it does more than indicate the size of the disc—it indicates family
ties with the highly successful compact cassette. Philips and Sony
had already worked to establish this standard in the magnetic tape
format and aimed to make their compact disc the standard for digital
sound reproduction.Philips and Sony began to demonstrate their compact digital disc
(CD) system to representatives of the audio industry in 1981. They
were not alone in digital recording. The Japanese Victor Company, a
subsidiary of Matsushita, had developed a version of digital recording
from its VHD video disc design. It was called audio high density
disc (AHD). Instead of
the small CD disc, the AHD
system used a ten-inch vinyl
disc. Each digital recording
system used a different
PCM chip with a
different rate of sampling
the audio signal.The recording and electronics
industries’ decision
to standardize on the Philips/
Sony CD system was
therefore a major victory for
these companies and an important
event in the digital
era of sound recording.
Sony had found out the
hard way that the technical
performance of an innovation is irrelevant when compared with the politics of turning it into
an industrywide standard. Although the pioneer in videocassette
recorders, Sony had been beaten by its rival, Matsushita, in establishing
the video recording standard. This mistake was not repeated
in the digital standards negotiations, and many companies were
persuaded to license the new technology. In 1982, the technology
was announced to the public. The following year, the compact disc
was on the market.
The Apex of Sound Technology
The compact disc represented the apex of recorded sound technology.
Simply put, here at last was a system of recording in which
there was no extraneous noise—no surface noise of scratches and
pops, no tape hiss, no background hum—and no damage was done
to the recording as it was played. In principle, a digital recording
will last forever, and each play will sound as pure as the first. The
compact disc could also play much longer than the vinyl record or
long-playing cassette tape.
Despite these obvious technical advantages, the commercial success
of digital recording was not ensured. There had been several
other advanced systems that had not fared well in the marketplace,
and the conspicuous failure of quadrophonic sound in the 1970’s
had not been forgotten within the industry of recorded sound. Historically,
there were two key factors in the rapid acceptance of a new
system of sound recording and reproduction: a library of prerecorded
music to tempt the listener into adopting the system and a
continual decrease in the price of the playing units to bring them
within the budgets of more buyers.
By 1984, there were about a thousand titles available on compact
disc in the United States; that number had doubled by 1985. Although
many of these selections were classical music—it was naturally
assumed that audiophiles would be the first to buy digital
equipment—popular music was well represented. The firstCDavailable
for purchase was an album by popular entertainer Billy Joel.
The first CD-playing units cost more than $1,000, but Akio Morita
of Sony was determined that the company should reduce the
price of players even if it meant selling them below cost. Sony’s audio engineering department improved the performance of the
players while reducing size and cost. By 1984, Sony had a small CD
unit on the market for $300. Several of Sony’s competitors, including
Matsushita, had followed its lead into digital reproduction.
There were several compact disc players available in 1985 that cost
less than $500. Sony quickly applied digital technology to the popular
personal stereo and to automobile sound systems. Sales of CD
units increased roughly tenfold from 1983 to 1985.
Impact on Vinyl Recording
When the compact disc was announced in 1982, the vinyl record
was the leading form of recorded sound, with 273 million units sold
annually compared to 125 million prerecorded cassette tapes. The
compact disc sold slowly, beginning with 800,000 units shipped in
1983 and rising to 53 million in 1986. By that time, the cassette tape
had taken the lead, with slightly fewer than 350 million units. The
vinyl record was in decline, with only about 110 million units
shipped. Compact discs first outsold vinyl records in 1988. In the ten
years from 1979 to 1988, the sales of vinyl records dropped nearly 80
percent. In 1989, CDs accounted for more than 286 million sales, but
cassettes still led the field with total sales of 446 million. The compact
disc finally passed the cassette in total sales in 1992, when more
than 300 million CDs were shipped, an increase of 22 percent over
the figure for 1991.
The introduction of digital recording had an invigorating effect
on the industry of recorded sound, which had been unable to fully
recover from the slump of the late 1970’s. Sales of recorded music
had stagnated in the early 1980’s, and an industry accustomed to
steady increases in output became eager to find a new product or
style of music to boost its sales. The compact disc was the product to
revitalize the market for both recordings and players. During the
1980’s, worldwide sales of recorded music jumped from $12 billion
to $22 billion, with about half of the sales volume accounted for by
digital recordings by the end of the decade.
The success of digital recording served in the long run to undermine
the commercial viability of the compact disc. This was a playonly
technology, like the vinyl record before it. Once users had become accustomed to the pristine digital sound, they clamored for
digital recording capability. The alliance of Sony and Philips broke
down in the search for a digital tape technology for home use. Sony
produced a digital tape system calledDAT, while Philips responded
with a digital version of its compact audio tape called DCC. Sony
answered the challenge of DCC with its Mini Disc (MD) product,
which can record and replay digitally.
The versatility of digital recording has opened up a wide range of
consumer products. Compact disc technology has been incorporated
into the computer, in which CD-ROM readers convert the digital
code of the disc into sound and images. Many home computers have
the capability to record and replay sound digitally. Digital recording
is the basis for interactive audio/video computer programs in which
the user can interface with recorded sound and images. Philips has
established a strong foothold in interactive digital technology with its
CD-I (compact disc interactive) system, which was introduced in
1990. This acts as a multimedia entertainer, providing sound, moving
images, games, and interactive sound and image publications such as
encyclopedias. The future of digital recording will be broad-based
systems that can record and replay a wide variety of sounds and images
and that can be manipulated by users of home computers.