By the end of the 1970s, stereo cassette tape machines were a cherished fixture in many homes and automobiles. However, truly portable units with built-in speakers or for use with headphones were limited to monaural sound.

In 1978, Sony added the small TC-D5 stereo model to its well-known Densuke series of portable tape recorders. Although popular among audiophiles, the TC-D5 was too heavy to be truly portable and the cost was prohibitive at 100,000 yen.

Ibuka (then Honorary Chairman) was a regular user of the TC-D5, and he would take one with a set of headphones on overseas trips, so that he could listen to music in stereo on the plane. However, he found it too heavy. One day, before going on atrip to the United States, he asked Ohga (then Executive Deputy President) for a simple, playback-only stereo version of the Pressman, the small, monaural tape recorder that Sony had launched in 1977. Ohga immediately called Kozo Ohsone, general manager of the Tape Recorder Business Division.

Ohsone immediately replied, Yes, yes, I'll do it. He had his staff alter a Pressman, removing the record function and converting the machine to produce stereo sound. They then attached headphones and tried this creation. The resulting sound was actually quite good. Shortly after, Ohsone and his staff were working on this rather strange-looking combination of large headphones and a small Pressman, when Ibuka visited them to discover if theyhad created what he requested. Always interested in products under development, Ibuka had a habit of dropping in at Sony's various laboratories.

A prototype with large headphones. >>>

Ohsone suggested that Ibuka try the modified Pressman. Ibuka was pleasantly surprised by the powerful sound that came from such a small device, and he was reminded of the first time he had listened to stereo sound through binaural headphones at the 1952 Audio Fair in the United States.

Ohsone managed to provide a modified version of the Pressman in time for Ibuka's business trip, but it worked with small, special batteries. Ohga presented Ibuka with the unit, together with two batteries thathe had an engineer from Ohsone's group rush around Akihabara (an electronics-shopping district in Tokyo) to find and a selection of classical music tapes.

Ohga's relief was short-lived. He received a call from Ibuka in the U.S., who said, The batteries ran out on the plane, and I can't find any replacements over here. Ohga also realized that the tapes he gave Ibuka were blank, and he hurriedly called CBS Records in the U.S. to ask them to prepare a selection of music tapes for Ibuka.

Despite all this, when Ibuka returned from the U.S. he was obviously pleased with the unit, even if it had large headphones and lacked a record function. Ibuka went to Morita (then Chairman) and said, Try this. Don't you think a stereo cassette player that you can listen to while walking around is a good idea? Morita took it home to try over the weekend, and he was also impressed. He agreed with Ibuka that the sound was quite different compared to conventional speakers, and he was excited by the fact that the device could be carried around easily, creating a personal listening experience. Morita's business acumen alerted him to the great potential of this new item.

Morita & Ibuka from Sony about headphones

Morita was completely absorbed in the new business. While Ibuka was adept at spotting new and interesting technologies and motivating his staff to develop them, Morita was the one who had the vision required to turn technologies into products. Since the founding of Sony, the two men had combined these different, but complementary, talents to great effect.


Morita said to Ibuka, This product is going to enable young people to listen to music anytime, anywhere. But the headphones are bigger than the device itself. Can't we do something about that? On hearing that, Ibuka remembered an R&D meeting two or three months earlier, at which there was talk of developing lightweight, open-air type headphones.

The H-AIR MDR-3 model. -->>>

Sure enough, when he went to the Research Laboratory, he found exactly what he was looking for. The development of the compact and extremely lightweight H-AIR MDR3 headphones was virtually finished. While most conventional headphones at that time weighed between 300 to 400 grams, the H-AIR headphones weighed just 50 grams. Furthermore, the new headphone driver units that fitted over the listeners' ears were only 23 millimeters across, much smaller than the 56-58 millimeters that was normal for the oval-shaped, earmuff type headphones developed previously. Despite being so small and light weight, the headphones produced great sound.

The H-AIR headphones were included in the portable stereo project in March 1979. Between them, Morita and Ibuka had successfully brought together technologies developed independently by different sections of Sony.

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