The game-changing CD is 30 years old


Saturday, October 06, 2012

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You may not be aware of it, but this week marks an important milestone in the world of consumer technology. The Compact Disc, or CD, is now 30 years old. On October 1, 1982, Sony put its first CD player, the CDP-101, on the market in Japan. And although discs had been pressed before that, the first CD to be released commercially was 52nd Street by Billy Joel. Sales were a bit slow at first, because both the discs and the machines were quite expensive, but they soon took off and before long the CD's predecessor, the LP, fell out of favour and began disappearing from record-store shelves. The pioneering Dutch electronics firm, Philips, called it the Compact Disc because the company had enjoyed enormous success with its Compact Cassette, which evolved from a system originally meant to take office dictation.

The CD was a quantum leap in the pursuit of audio perfection which began 135 years ago when Thomas Alva Edison recited Mary had a little lamb and embossed it on a sheet of tinfoil wrapped around a grooved tube he turned with a crank. That first recording used a cone to focus the sound onto a needle at the small end, and as this needle wiggled back and forth it traced a groove in the soft metal. The sound was (to coin a word) tinny but impressive, since this was the first time someone could hear his own voice without cupping his hand around his ear as he spoke.

Edison's device was an important breakthrough all right, but the cylindrical format made it impractical to produce large numbers of copies. This wasn't rectified until more than a decade had passed, when Emil Berliner, a German-born immigrant, found a better way - discs. Producers could now make master discs from which thousands of copies could be pressed. Playing time was also doubled because music was stored on both sides. Within a very short while cylinders fell by the wayside, so much so that Edison established his own disc-recording business. Early records ran at various speeds but eventually 78 revolutions per minute became the standard, remaining so until the development of the long-playing record in the 1950s at the then unbelievable speed of 33 1/3 rpm. The early discs were made of wax, later replaced by shellac - excretions from a tiny insect mixed with varnish. Later, discs were made of a plastic called vinyl, which was lighter and less fragile.

At first, the sound was imprinted on the discs by a stylus vibrating directly by the air in a big horn. This same set-up was used to play the sound back. In the 1920s, engineers began using electronic means of capturing the sound. Instead of the cumbersome horn, the sound is picked up by a microphone using a small diaphragm attached to an electrical coil and magnified by an electronic amplifier to be fed through a loudspeaker. Over the ensuing years, improvements in the technology allowed engineers to produce sound approaching the elusive goal of being lifelike.

The early records wore out quickly under the considerable weight of the horns and bulky needles and even the later electrical pickups using styli made of sapphires or artificial gems. By the 1950s, when the long-playing record came along, pickup cartridges had become considerably lighter and the much smaller grooves and slower speeds (33 1/3 and 45 rpm) allowed much more playback time compared with the three minutes imposed by the limitations of the 78 rpm platter.

During the second world war, German engineers devised a method of capturing sound with much improved quality on strips of paper coated with fine magnetic particles. The US Army Signals Corps took samples of this magnetophon (German for tape-recorder) back home after the war and soon several companies began manufacturing versions of them.

Engineers tinkered constantly with their audio equipment and by the early 1950s built machines which could record sound the way our ears hear it - stereophonically. Using two or three channels, each picking up the sound from a slightly different point of view, they added the dimension of space. They eventually found a way to put those two tracks into one groove on a record, and a new sound revolution was on.

The system of recording up to this point is what scientists call analogue, in that the sound is stored either as a direct representation of the vibrations as physical wiggles in a plastic groove, or variations of a magnetic field of minute iron filings stuck onto a piece of plastic tape. Constant tweaking improved to a very high degree the quality of the sound produced, but engineers had to rely on a variety of dodges to get around some inherent problems - noise from dust, scratches and wear and tear of record grooves as well as hiss generated when magnetic tape passes through a machine. The motors and guiding mechanisms had to be manufactured and maintained at very high standards to avoid fluctuations in speed and the pickup cartridges, amplifiers and loudspeakers had to be of the best quality to avoid distorting the music.

The solution, although not obvious at first, was the digital revolution brought in by the computer. As complicated as a computer appears, it works on an extremely simple basis - electrical signals which are either on or off. Scientists quickly devised a language based on ones and zeroes, representing the ons and offs. From as early as the 1960s, some engineers began thinking of a way to convert sound into ones and zeroes, and by the early 1970s Philips and Sony independently produced prototypes.

By 1979 they set up a joint task force to work out the details of the new recording system. They eventually agreed on a disc 12 centimetres in diameter capable of holding 74 minutes of recorded music.

Progress is a funny thing. The very feature which defines the CD as an ideal storage medium for music has led to its dramatic decline for that very purpose. Although it was designed for music, computer engineers loved its large storage capacity and co-opted it.

So now we have various configurations of CD-ROMs used to store spread-sheet displays for use at next week's board meeting, architectural drawings for a prospective client, technical specifications for intricate mechanical parts or pictures and video from your daughter's graduation. Now, everybody downloads music online into solid-state storage devices like the MP3, memory stick or cellphone.

I still recall the very first CD I ever heard. It was some months before the actual release. A fellow from Sony Canada had brought a machine to the CBC, where I worked, to demonstrate the new system for an audiophile programme. He picked up the machine in Japan and for security reasons had to sign a document agreeing not to let it out of his sight for the entire trip back. After listening to some sample CDs, my colleagues and I were impressed by how clean and clear the sound was. One of them, a hi-fi aficionado, remarked, "And the best thing is, one year from today, unlike an LP, it will sound exactly the same!"




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