mainstreetCD

History of the CD

Born from an intense collaboration between several major names in the electronics industry – Sony and Philips in particular – and the music industry, CD players arrived on the Japanese market on October 1, 1982, and from February 23, 1983 in the rest of the world. In order to more easily locate the appearance of this format in France, it will be recalled that March 1983 saw the launch of the PEUGEOT 205. This parallel may seem insignificant, but it clearly shows that data storage on optical discs and their reading by laser are very recent technologies. However, the past 35 years have seen the advent of the PCM audio encoded CD, its apogee and its programmed disappearance, gradually giving way to hard disks and static memories, for the storage of often compressed audio data (with or without losses, MP3, Flac, etc.).
More than 250 models of CD players of all brands were produced in the two years following the launch of the CD standard, i.e. between late 1982 and early 1985. These are mainly the so-called first and second generation readers, the second generation machines having appeared in Japan since the first quarter of 1983, with the Lo-D DAD-800. The first machines available in Japan, SONY CDP-101, HITACHI DA1000, MARANTZ CD63, were quickly joined by other legendary machines, such as the TECHNICS SL-P10, SHARP DX-3 or the PIONEER P-D1. Concerning these very first readers marketed, i.e. the machines that appeared between the end of 1982 and the beginning of 1983, there are 3 categories: originals, semi-originals and clones (or partial clones).

➔ The originals (SONY CDP-101, Philips CD100, Technics SL-P10, Hitachi DA-1000), are readers with a new design and technology, with an original aesthetic, and adopting a new mechanical / electronic configuration, as well as a specific internal organization of the different printed circuits.

➔ Semi-original readers are readers with a totally new aesthetic but using mechanical / optical and / or electronic technologies (digital processing and D/A conversion) borrowed from readers (brands) in the first category. Among these “semi-original” are the Toshiba XR-Z90, Yamaha CD-1, Aiwa DX-1000,Mitsubishi DP-101, Kyocera DA-01, Sanyo DAD-8, NEC CD803, Pioneer P-D1, Sharp DX-3 and some others.

➔ The clones represent a large number of readers from major brands such as JVC, Akai, Luxman, Denon, Grundig, Kenwood and others. Indeed, many manufacturers have chosen, for economic reasons, to adopt an existing model for the first model in their catalogue. They only expressed their creativity from the second generation of readers, when they did not adapt (adopt) an existing model again. These copies have been more or less successful and have been more or less original, with each brand making its own aesthetic and sometimes practical changes. Thus, all copies of the highly cloned Lo-D DAD-800 (Japanese name for the Hitachi DA800) had a standard infrared remote control, while the original only had an optional wired remote control.
In 1985, the prestigious American manufacturer McIntosh presented a luxurious copy of the Philips CD304, for its first MCD7000 player. Only a trained eye could recognize the masking, which was also very judicious, since this imitation required an additional expense of more than 20,000 FF (!), compared to the original Dutch brand.
Until 1985, the beginning of the great standardization of CD players (black, horizontal drawer loading, standard width…), the most cloned brands were Hitachi, Toshiba, Sanyo, Kyocera and Yamaha.
Despite the many clones, the consumer had a wide aesthetic choice (if not a wide technical choice). The manufacturers offered a jumble of readers with front disc loading, horizontal by drawer, or by trapdoor on the upper part (Philips). Their physical proportions ranged from “small cube” to standard lounge size, and their weight varied from 4 to more than 14 kg.
Nevertheless, CD players produced between 1982 and 1985 carried a variety of highly sophisticated and sophisticated reading devices, reflecting the willingness of their original designers to manufacture high-performance and reliable machines. This commendable commitment, guaranteed by the frequent use of quality components and materials (mechanical, chassis, electronics), lasted only a few years and the metal quickly gave way to plastic materials for moving parts (including the optical compartment) for obvious reasons of production cost. However, the significant drop in the manufacturing quality of consumer readers was largely compensated technically by the increased performance of servo systems (electronic servo systems for controlling mechanical elements), by allowing less “adjusted” assemblies.


 

The technologies used by the Compact Disc system result from the natural evolution of the technical knowledge accumulated by man over more than 150 years. However, it is possible to target the real beginning of the work undertaken in the so-called “digital” audio field, in the early 1970s with the research work in electronics and on Servo-systems concerning the Videodisc started by Philips in 1973.

Note: It should be recalled that the videodisc was a 30cm diameter disc that could store more than 60 minutes of video and audio by analog FM modulation. A kind of DVD that is heavier, wider and less reliable. In 1975, the launch of the Philips Videodisc – the VLP (Video Long PLay) – was a real technological success but a formidable commercial failure since consumers showed no interest at all.
Technically, the machine was equipped with a Helium / Neon gas laser with a wavelength of 630nm, manufactured by Philips. The project evolved towards ALP (Audio Long Play) identical to VLP but adapted to the storage of audio data in addition to video.
Unfortunately, the principle of analog signal engraving caused too much signal interference. So after two years, Philips threw in the towel and removed the VLP from the market, and a decision was made to use digital coding.

During this period, a few engineers from Philips’ audio department were appointed to develop an audio disc based on optical video disc technology.
They continued to explore an analog system using broadband frequency modulation, as in FM radio, and their various experiences showed that the solution of analog disk recording did not solve the problems of dirt and dust encountered on conventional 33T discs.
Three years later, they decided to move to a digital application. Thus, in 1976, Philips presented its first prototype of a digital audio disc using laser-readable video disc technology (a year later, Sony completed a prototype 30cm in diameter, with a 60-minute playback time).
In 1977, Mitsubishi and Hitachi presented their prototype DAD (Digital Audio Disc) at the Audio Fair in Japan. We will see later that several manufacturers had engaged in the race for digital audio. The same year, the name “Compact Disc” was suggested for the system, after the proposals “Mini Disc”, “Mini Rack” or even “Compact Rack” were abandoned.
In October 1979, the historic decision was made to bring together existing talent to develop a global standard for audio discs.
Although Philips and Sony were in constant competition, they had long cooperated in several areas such as the development of the compact cassette in the early 60’s. An
important point was that both brands held a leading position in the music industry through CBS / Sony and Polygram.

A few weeks were enough to form a working team and between 1979 and 1980 a large number of meetings took place between Tokyo and Eindhoven. The first in August 1979 in Eindhoven, and the second in October 1979 in Tokyo were used by the engineers of both groups to get to know each other and discover their strengths and specialities. The two firms had presented a prototype and a decision was made to take the best of each other.
During a third meeting in December 1979, the two parties drew up a list of the characteristics they envisaged for the future digital audio disc. It turned out that the only criterion common to both lists (Philips and Sony) was the maximum possible playback time, 60 minutes.
It remained to be agreed on the sampling frequency, quantification, disc diameter, as well as the error correction code and the way in which the data was organized and recorded on the disc (the “channel code”).
In 1978, all existing digital audio equipment used their own sampling frequency ranging from 32 kHz to 50 kHz. While current digital audio equipment accepts several sampling frequencies, it was decided for the CD to choose only one, 44.1 kHz. This frequency was adopted for various reasons:
First, Shannon-Nyquist’s theorem stipulates that the initial audio signal should be sampled at a frequency at least twice that of its bandwidth.
Therefore, a frequency of at least 40 kHz would be required for a bandwidth of 20 kHz, 20 kHz corresponding to the maximum average frequency perceived by a young age individual. Then, in the late 1970s, several PCM converters were developed in Japan, which used conventional analog band recorders for digital data storage, making them the only recorders on the market with sufficient bandwidth to store this data. The most common format at the time was U-Matic 3/4″. The existence of these PCM adapters for video explains the choice of CD sampling frequency, since the number of lines, frame rate and number of bits per line dictated the possible frequency for the digital audio disc.
Thus, the sampling frequencies of 44.1 and 44.056 kHz were a direct result of the need for compatibility with NTSC and PAL video standards. And since there were no other reliable recorders on the market at the time offering other sampling frequency options, the partners Sony and Philips had no choice but to choose between 44.1 and 44.056 kHz.

Note: the available PCM adapters were in the order of appearance the SONY PCM-1600, PCM-1610 and PCM-1630, until the 1990s, only video cassettes could be used as a means of transfer from recording studios to mastering laboratories. Later on, other systems replaced it, such as CD’Rs and Memory sticks.

Finally, the audio quality of the CD would therefore be that of the Sony PCM-1600 converter, since there was no other logistical choice.

(In the recording process, the life of an audio CD began on a PCM Master tape, recorded on a U-Matic video cassette on which analog data was converted to digital data overlaying a standard television signal, until the late 1980s)

During the fourth meeting in Tokyo in March 1980, Philips accepted (following Sony’s first proposal) a resolution of 16 Bits and a sampling frequency of 44.1 kHz (which was preferred because it was easier to remember!).
Philips temporarily abandoned its wish to use 14-bit resolution (the brand had no rational technical reason other than its existing 14-bit Digital to Analog converter), before changing its mind and realizing that it was possible to delete 1 Bit per word at a constant rate each time the sampling frequency doubled. As a logical consequence, the deletion of 2 bits from 16 to 14 required a quadrupling of the frequency of the Digital to Analog conversion system to a frequency of 176.4 kHz. This “oversampling”, thanks to the addition of a digital filter (SAA7030 on the brand’s first players), made it possible to develop an analog filter with a gentle slope at the output, improving linearity around the highest audio frequencies. Incidentally, this solution allowed Philips to use its existing stock of 14-bit converters.