Specifications
- Release price: ¥168,000 (released in 1982)
- Frequency response: 5Hz–20kHz ±0.5dB
- Total harmonic distortion: 0.004% or less (1kHz)
- Dynamic range: over 90dB
- Wow and flutter: below measurable limits
- Power consumption: 23W
- Dimensions: W350 × H105 × D325mm
- Weight: 7.6kg
In the 1980s Japan stood at the pinnacle of the global audio industry. The Compact Disc, often called the “dream medium” when it appeared in 1982, was developed through the leadership of two companies: Philips, which proposed the concept, and Sony of Japan.
Behind the scenes of the CD standard were intense negotiations and technical conflicts between the two companies. The result of those efforts was the first CD player, the Sony CDP-101 — a product that marked one of the greatest turning points in the history of audio.
A Genius of Transducers
Heitaro Nakajima:
Graduated from the Department of Electrical Engineering at the Tokyo Institute of Technology. After serving as Director of NHK Science & Technology Research Laboratories, he joined Sony and became head of its Technical Research Center. At Sony he was involved in numerous innovative products, and in 1984 he became president of Aiwa. During his tenure, Aiwa released the world’s first DAT recorder, the XD-001.
NHK Science & Technology Research Laboratories (NHK STRL) is widely known today for its work on 8K broadcasting, but in earlier decades it functioned as a public institution that supported the advancement of audio technology.
In the difficult years after World War II, Japanese electronics manufacturers had to develop new products and technologies despite severe shortages of funding and personnel. NHK STRL played an important role in supporting those efforts behind the scenes. Using public funding and some of the best engineers in Japan, the laboratories conducted research into record styli, speakers, recording equipment, and other broadcasting technologies.
NHK itself could not manufacture commercial products, so the technologies developed there were transferred to specialized manufacturers, who then built the equipment. At the same time, those manufacturers applied the technology to consumer products, improving and refining them. This system helped Japanese electronics — especially audio technology — evolve at an unprecedented pace in the postwar era.
One of the researchers at NHK STRL was Heitaro Nakajima.
Today Nakajima is known as the “father of the Compact Disc,” but originally he was recognized as a genius in the field of transducers — the conversion between sound and electrical signals. From record styli to microphones and speakers, he possessed both extraordinary intuition and remarkable persistence as a developer.
Eventually Nakajima began developing digital recording equipment under Kenji Hayashi, known for PCM recording systems and the R&P combination head used in professional recorders.
“Originally we were trying to improve the sound quality of FM broadcasting,” Nakajima once explained when recounting those early days.
However, development of the digital recorder proved extremely difficult. Despite consuming enormous budgets, the project struggled to produce tangible results, and the research program was eventually cancelled.
Years later Nakajima became director of NHK STRL. Because public funds were used in the laboratory, all research programs had to be presented to the Broadcasting Technology Council, a committee of outside experts that reviewed progress and future plans.
One of the members of that council was Sony founder Masaru Ibuka.
At Ibuka’s invitation, Nakajima eventually moved from NHK to Sony.
The Birth of the PCM Processor
Have you ever wondered why the CD sampling frequency is such an odd number: 44.1kHz?
The answer lies in video technology. Early PCM recorders used video tape as their recording medium, and the sampling frequency was derived from the scanning line frequency of the PAL video system.
When Nakajima joined Sony, Ibuka told him, “You may build your own research laboratory.” Nakajima established Sony’s Technical Research Center. However, Ibuka was opposed to the idea of pursuing digital recording research.
“He would say that cutting and editing signals with thousands of switches goes against the philosophy of ‘Simple is Best,’” Nakajima once recalled.
But because Sony’s research center was located in Shibaura while the headquarters was in Gotanda, Nakajima quietly continued digital recording research anyway.
“I saved small amounts of money from other research budgets,” he said with a smile. “And when we needed manpower, I borrowed students from a professor I knew at Waseda University.”
The result of these quiet efforts was the PCM-1, the first consumer PCM processor.
This system converted digitized audio into a video signal and recorded it onto videotape. Through the development of the PCM processor, Sony accumulated valuable knowledge about handling digital audio data.
In particular, engineers discovered that data loss inevitably occurred when recording and reading digital information. To address this, the concept of error correction was introduced — a technology that would later prove essential to the reliability of the Compact Disc.
The Development of the Digital Audio Disc
At one point, members of Sony’s PCM development team joined engineers from EMI in Salzburg to make a test recording of conductor Herbert von Karajan during rehearsal.
Later, when Karajan visited Japan, Sony chairman Akio Morita invited him to dinner and played back the recording.
Karajan was initially angry that the recording had been made without his permission. But once he heard the sound quality, he was impressed.
“Digital recording shouldn’t be limited to tape,” he reportedly said. “It should be put onto a disc.”
In fact, Sony had already begun developing what was called the Digital Audio Disc (DAD).
Since LaserVision (LaserDisc) already existed, Sony engineers quickly decided that DAD should use optical disc technology. Using LaserVision discs as a starting point, they built a prototype 30cm digital audio disc.
Interestingly, another group within Sony was developing DAD using a different method. Around 1978, Philips — the original developer of LaserVision — visited Sony to demonstrate their own DAD prototype.
The disc was compact: 11.5cm in diameter, the same length as the diagonal of a cassette tape. The player itself was also compact and elegant.
One engineer who witnessed the demonstration later said:
“Of course there was a huge main unit hidden under the table supporting the player, but the way they presented it was very clever.”
Nakajima later reflected:
“They explained that eventually the entire large unit would be integrated into a single LSI chip. It was an excellent concept.”
The impact of Philips’ prototype was enormous. Within a month of that demonstration, Sony decided to jointly develop the digital audio disc with Philips.
Two Giants in Conflict
With Philips — the pioneer of optical discs — and Sony — the developer of the world’s first digital audio recorder — working together, the development of the optical digital audio disc seemed destined for success.
In reality, however, engineers from the two companies frequently clashed.
The biggest disagreements concerned error correction and reading accuracy.
Philips assumed that digital data should be read perfectly. Their development therefore focused on improving disc quality and laser pickup precision.
Sony’s engineers, having worked extensively with PCM processors, believed that data loss and reading errors were inevitable. Their approach was to embed error-correction codes within the data so that playback could continue smoothly even when errors occurred.
As a result, Sony placed less emphasis on disc perfection itself.
Philips engineers were reportedly shocked when they saw Sony’s prototype discs, which sometimes contained tiny bubbles in the resin layer covering the recording surface.
But thanks to Sony’s robust error-correction system, even such imperfect discs could play without interruption.
Ultimately, the final system combined Sony’s resilient data structure with Philips’ high-quality optical discs — resulting in an extremely reliable format.
The conflicts didn’t end there.
Both companies agreed that the disc should hold Beethoven’s Ninth Symphony — about 74 minutes — but Philips wanted an 11.5cm disc with 14-bit data, while Sony insisted on a 12cm disc with 16-bit resolution.
Philips argued that affordable 16-bit DACs did not yet exist, and that 14-bit resolution already provided more than 80dB of dynamic range.
Nakajima refused to compromise. If 16-bit DACs existed — even if expensive — the format should aim for the highest possible quality. A 12cm disc, he argued, could accommodate the extra data.
Eventually the presidents of both companies became involved. Morita reportedly tried to persuade Nakajima to accept 14-bit resolution.
Nakajima countered that a 16-bit format could one day store computer data as well. He even suggested asking Karajan to help persuade Philips.
“I don’t know whether Morita actually called Karajan,” Nakajima later said with a smile. “But in the end, the decision was made: a 12cm disc with 16-bit data.”
The digital audio disc created through the combined expertise of Philips and Sony was named the Compact Disc — essentially a disc version of the compact cassette.
An All-Japan CD Player
Even after the CD format had been finalized, enormous challenges remained.
For example, engineers had to decide how much disc wobble or warping should be allowed in the standard. Experiments showed that the laser could still read data even when tilted by 1.2 degrees. But determining acceptable limits required difficult decisions.
“In the end we simply split the difference,” Nakajima recalled. “We allowed 0.6 degrees for both wobble and warp. But even after deciding, I couldn’t sleep for a day or two wondering if it had been the right choice.”
At the same time, Sony also had to develop an actual CD player — something impossible for one company to accomplish alone.
Sixteen-bit DACs were extremely expensive at the time, so Sony had to develop its own. The error-correction system required 2KB of memory — also very costly.
Nakajima later recalled asking Fujitsu to develop suitable memory chips:
“The vice president of Fujitsu happened to be an audio enthusiast. He agreed to help.”
Semiconductor lasers for the optical pickup were manufactured by companies such as Hitachi, Fujitsu, and Sharp. Hitachi’s lasers had excellent spectral purity but were extremely sensitive. Sharp’s lasers were technically inferior but much tougher and more practical.
Lenses, motors, and servo systems — most key components of the CD player — were produced by companies other than Sony.
“In Japan we had all the best technologies necessary to build a CD player,” Nakajima said. “Japanese electronics were at the peak of the world. Rather than doing everything ourselves, it was better to entrust each component to the company best suited to it.
It was an All-Japan effort.”
Philips, which began development at the same time, released its first CD player slightly later than Sony — perhaps because Europe lacked manufacturers capable of producing certain key parts.
The First CD Player
Sony released the CDP-101, the world’s first CD player, in October 1982.
The previous year Sony had exhibited a prototype at the Audio Fair. Nicknamed “Goronta,” it used a vertical disc-loading design.
Many early CD players from other manufacturers adopted similar vertical loading mechanisms. One engineer later admitted:
“After seeing the Goronta, it was hard to imagine anything else.”
However, Sony had already decided that its first commercial model would use a horizontal tray.
Nakajima explained:
“Because the disc is servo-controlled, it can operate vertically, horizontally, or even at an angle. But we felt a horizontal design would make it easier to handle the disc. Still, we built the prototype vertically just to test the idea.”
After building it, he laughed and concluded:
“The vertical design turned out to be very difficult.”
Most manufacturers that released vertical players quickly switched to horizontal designs in later models.
The CDP-101, completed through Sony’s leadership and the cooperation of Japan’s electronics industry, measured only 35cm wide — about the size of a compact component.
However, it weighed a hefty 7.6kg, reflecting the technological limits of the era.
Nakajima personally delivered the very first unit to Sony founder Masaru Ibuka, who had once opposed digital audio.
Ibuka reportedly said:
“You’ve worked very hard to get this far. Thank you.”
But as Nakajima was leaving, Ibuka added with a smile:
“Still… analog is wonderful, isn’t it?”
Nakajima passed away in December 2017, one year after I interviewed him.
During our final conversation, when the topic turned to the high-resolution audio boom, he said:
“Increasing resolution isn’t a bad thing. But we must consider the entire system — the microphones used during recording, the speakers used for playback, everything.
In that sense, the CD format still has plenty of life left in it. Even now, I spend my time thinking about how to make CDs sound better.”
Until the very end of his life, the genius of transducers continued nurturing the Compact Disc he had helped create.