Melbguy1
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Hi folks, re-posting this article with permission from DCS 
..
History of Digital - part 1
From its raw beginnings to the future as it is now being made – in the first of this four-part feature we begin to tell the story of digital audio…
In 2017, Compact Disc becomes thirty five years of age. The format was jointly announced by Philips and Sony on the 1st October, 1982 – and slowly began to get to market by the early part of the next year. Although it’s fallen out of fashion a bit now, it has nevertheless proven to be immensely popular over a long period of time, in most parts of the world. Recorded music changed when Philips announced the new format that offered – as the advertisements said – “pure, perfect sound forever…”
CD didn’t arrive a moment too soon. Back in 1982, sales of LP records were on the wane – falling by 9% that year. The format was over thirty years old, and as with every other consumer product, nothing lasts forever. The number was down to 57.8 million per year in the UK from 1975’s high watermark of 91.6 million. And as less money was being made, so the record companies had been steadily taking the quality out of the format. Whereas early seventies albums were exquisite pieces of work pressed on fresh vinyl with lavish gatefold sleeves, early eighties pressings were done flimsily and on the cheap. Record warps and surface imperfections conspired to alienate ever more music buyers.
Compact Disc brought together big science and big business. In terms of technology, it comprised two ingenious ideas – digital audio coding and optical disc storage. One could say that the invention of sampling theory in 1841 by Augustin-Louis Cauchy was what started the ball rolling. Then, in his 1928 lecture to the American Institute of Electrical Engineers, Harry Nyquist proved the idea could work. A. Reeves later proposed pulse code wave modulation (PCM) as a way of storing audio in 1937, then work at Bell Labs in 1948 yielded arguably digital audio’s most significant breakthrough – when John Bardeen, William Shockley and Walter Brattain’s bipolar junction transistor made compact digital circuitry a reality. Finally, I.S. Reed and G. Solomon’s work on error correction codes in 1960 gave us the technology that would be directly applied to Compact Disc twenty two years later.
As far as optical disc storage is concerned, it was the 1958 invention of the laser by C.H. Townes and A.L. Shawlow that made it all possible. Dutch physicist Klaas Compaan’s work – using a glass disc to store black and white holographic images using frequency modulation at Philips Laboratories in 1969 – was the next step. Four years later, Philips engineers began to plan an audio application for their prototypical videodisc system – this ran a 44kHz sampling rate through a 14-bit digital-to-analogue converter. Japan’s NHK Technical Research Institute publicly demonstrated a digital audio recorder running 12-bit resolution and a 30kHz sampling rate in 1967. Before the decade was out, Sony had a 13-bit machine running at 47.25kHz.
Everything came together at the 1977 Tokyo Audio Fair, which saw Sony, Mitsubishi and Hitachi all demonstrating digital audio discs, and then the next year Philips joined its software subsidiary Polygram to develop a world audio standard, which it demonstrated in early 1979. After Matsushita declined an invitation to join the standard, Sony signed up in 1980 and in June of that year the famous ‘Red Book’ specification for CD was formally proposed. A year later, Sharp successfully mass produced the semiconductor laser, making CD a commercial reality…
The original target capacity for a Compact Disc was one hour of audio content, and a disc diameter of 115 mm was sufficient for this, but in the end Philips and Sony agreed a 120mm disc capable of holding 74 minutes of 16-bit, 44.1kHz PCM music. This change resulted in CD being able to contain all of Beethoven’s 9th Symphony, whilst fitting inside a man’s suit pocket. This, as legend has it, was the original demand of Sony President Norio Ohga!
“When the new digital disc came out, audio engineers of the day regarded it as a great thing”, says dCS Director of Design, Andy McHarg. “In terms of dynamic range, 14-bit PCM already measured better than the vinyl LP, so the guys at Philips would have been really pleased to have got the CD specification written as 16-bit which gives 96dB of dynamic range – compared to vinyl’s 75dB or so…”
It might not sound much now (today’s 24-bit digital gives 144dB dynamic range, theoretically), but then it was running technology at the ragged edge, observes Andy. “You have to remember the limitations at the time, and fitting 650 megabytes of data on that disc was no mean feat with the state of technology as it was. The format exceeded the performance of any converters you could feasibly design at the time, giving engineers some wiggle room too – which is why it has endured into today’s high resolution world.”
..History of Digital - part 1
From its raw beginnings to the future as it is now being made – in the first of this four-part feature we begin to tell the story of digital audio…
In 2017, Compact Disc becomes thirty five years of age. The format was jointly announced by Philips and Sony on the 1st October, 1982 – and slowly began to get to market by the early part of the next year. Although it’s fallen out of fashion a bit now, it has nevertheless proven to be immensely popular over a long period of time, in most parts of the world. Recorded music changed when Philips announced the new format that offered – as the advertisements said – “pure, perfect sound forever…”
CD didn’t arrive a moment too soon. Back in 1982, sales of LP records were on the wane – falling by 9% that year. The format was over thirty years old, and as with every other consumer product, nothing lasts forever. The number was down to 57.8 million per year in the UK from 1975’s high watermark of 91.6 million. And as less money was being made, so the record companies had been steadily taking the quality out of the format. Whereas early seventies albums were exquisite pieces of work pressed on fresh vinyl with lavish gatefold sleeves, early eighties pressings were done flimsily and on the cheap. Record warps and surface imperfections conspired to alienate ever more music buyers.
Compact Disc brought together big science and big business. In terms of technology, it comprised two ingenious ideas – digital audio coding and optical disc storage. One could say that the invention of sampling theory in 1841 by Augustin-Louis Cauchy was what started the ball rolling. Then, in his 1928 lecture to the American Institute of Electrical Engineers, Harry Nyquist proved the idea could work. A. Reeves later proposed pulse code wave modulation (PCM) as a way of storing audio in 1937, then work at Bell Labs in 1948 yielded arguably digital audio’s most significant breakthrough – when John Bardeen, William Shockley and Walter Brattain’s bipolar junction transistor made compact digital circuitry a reality. Finally, I.S. Reed and G. Solomon’s work on error correction codes in 1960 gave us the technology that would be directly applied to Compact Disc twenty two years later.
As far as optical disc storage is concerned, it was the 1958 invention of the laser by C.H. Townes and A.L. Shawlow that made it all possible. Dutch physicist Klaas Compaan’s work – using a glass disc to store black and white holographic images using frequency modulation at Philips Laboratories in 1969 – was the next step. Four years later, Philips engineers began to plan an audio application for their prototypical videodisc system – this ran a 44kHz sampling rate through a 14-bit digital-to-analogue converter. Japan’s NHK Technical Research Institute publicly demonstrated a digital audio recorder running 12-bit resolution and a 30kHz sampling rate in 1967. Before the decade was out, Sony had a 13-bit machine running at 47.25kHz.
Everything came together at the 1977 Tokyo Audio Fair, which saw Sony, Mitsubishi and Hitachi all demonstrating digital audio discs, and then the next year Philips joined its software subsidiary Polygram to develop a world audio standard, which it demonstrated in early 1979. After Matsushita declined an invitation to join the standard, Sony signed up in 1980 and in June of that year the famous ‘Red Book’ specification for CD was formally proposed. A year later, Sharp successfully mass produced the semiconductor laser, making CD a commercial reality…
The original target capacity for a Compact Disc was one hour of audio content, and a disc diameter of 115 mm was sufficient for this, but in the end Philips and Sony agreed a 120mm disc capable of holding 74 minutes of 16-bit, 44.1kHz PCM music. This change resulted in CD being able to contain all of Beethoven’s 9th Symphony, whilst fitting inside a man’s suit pocket. This, as legend has it, was the original demand of Sony President Norio Ohga!
“When the new digital disc came out, audio engineers of the day regarded it as a great thing”, says dCS Director of Design, Andy McHarg. “In terms of dynamic range, 14-bit PCM already measured better than the vinyl LP, so the guys at Philips would have been really pleased to have got the CD specification written as 16-bit which gives 96dB of dynamic range – compared to vinyl’s 75dB or so…”
It might not sound much now (today’s 24-bit digital gives 144dB dynamic range, theoretically), but then it was running technology at the ragged edge, observes Andy. “You have to remember the limitations at the time, and fitting 650 megabytes of data on that disc was no mean feat with the state of technology as it was. The format exceeded the performance of any converters you could feasibly design at the time, giving engineers some wiggle room too – which is why it has endured into today’s high resolution world.”
