The first Walkman was the TPS-L2, a stereo audio cassette player with a set of compact, lightweight headphones. It was a product for which its developers held little hope, but with worldwide cumulative sales of Walkman from audio cassette, to CD and MD models amounting to around 250 million units over the last 25 years, they couldn?t have been more wrong about the desire of people to take their favourite songs with them.

The TPS-L2 was developed from Sony?s Pressman mono cassette tape recorder/player. Essentially, it removed the external speaker, added stereo playback and a set of fairly revolutionary earphones that, instead of the usual 300-400 grams, weighed just under 40. While named Walkman in Japan, it was initially marketed as ?Stowaway? in England, ?Soundabout? in the US and ?Freestyle? in Australia, and such was its success that, within a year, other companies had begun marketing similar portable music players.

From its first rudimentary incarnation, the Walkman range grew steadily in features and functionality, with auto reverse, splash resistant casings, rechargeable batteries, Dolby Stereo processing and wireless remotes being among the early innovations. And while initially developed for audio cassette, the Walkman family expanded to accommodate other types of media, including CD (1984), MiniDisc (1992), DVD (now referred to as Discman), Memory Stick (1999) and even the short-lived DAT – Digital Audio Tape format (1990). In total, over 300 different Walkman models were produced.

The Walkman was responsible for significantly changing the culture of music, and paved the way for today?s solid state, 1000-plus songlist personal audio players. The company responsible for this, however, was slow to jump onboard the next revolution in personal audio. While companies around it saw the potential of computer technology, MP3, the Web?s offer of free music, and the ever-shrinking size and cost of digital memory, Sony persisted with technologies that no-one seemed to want.

Based on expensive Memory Stick cards and its unpopular and proprietary MiniDisc and AATRAC formats, Sony?s Network Walkman and Hi-MD players failed to appeal. The company?s first hard disk-based models hit the market only in 2004, too late to take on the likes of iPod, the Walkman?s modern day successor.

Tales of invention

For years, Sony?s engineers took credit for the Walkman?s invention, but in early 2006, and following protracted court proceedings, the company paid seven million euros (close to $12 million) to German inventor, Andreas Pavel, who claimed he came up with the idea in 1972. He claimed to have patented the device in 1977, just two years before the release of the TPS-L2 and the beginning of Sony?s 20-year dream run with the Walkman.