When 70-year-old Masaru Ibuka, co-founder of Japan's world-renowned Sony Corp. requested that his engineers design and create a portable stereo cassette player for a long business trip, little did he know that his request would be opening up a revolutionary new frontier–'portable music.' To achieve Ibuka's dream, Sony engineers rewired the 'Pressman,' a small "mono" tape recorder at the time, which enabled it to play in stereo format via headphones.
On return from his trip, Ibuka was so impressed that he suggested that the new portable stereo tape recorder be put into full production. Ibuka was fully backed by fellow founder Akio Morita, who was convinced that young people would love it. The company was then given a challenging, four-month deadline to put the Walkman on sale before the summer holidays of 1979. The challenge was met and the first Walkman models hit the market. Initially, many retailers were skeptical about the Walkman's acceptance and thought it wouldn't sell as it did not have a "recording" feature. By 1989, however, 50 million Walkmans had been sold. The question you may ask is, "How does a Walkman work?" Well, the following should give you an idea of what the Walkman is all about.
The Walkman is a small cassette player with a pair of lightweight headphones. There are primarily two parts to any audio magnetic recording system–the audio cassette tape (used as the storage medium) and the recorder itself (which acts as the playback device).
The audio cassette tape used in a Walkman, or for that matter in any tape recorder, is coated with magnetic particles. If the cassette is blank (sans recorded music) the magnetic particles will point in random directions. However, when music is recorded, they will automatically fall into a pattern that is identical to the original sound waves. When the "Play" button is pressed, the tape passes over a reader "head" that contains the electromagnet, which is highly sensitive to the patterns recorded on the tape. The head then transmits a matching, electrical signal to the tiny diaphragms in each ear piece of the headphone causing them to vibrate and create audible music sound waves. This is basically how you hear your favorite music.
The Walkman consists of basic features to perform such functions as play, pause, rewind, fast forward, record and stop. In a basic Walkman cassette player, there are two heads, one of which contains two small electromagnets. These two heads record the two separate channels of a stereophonic program. The tape recorder has two sprockets that engage the spools within the cassette. During recording playback, fast forward or reverse, the two sprockets spin one of the spools to engage the tape to match the function desired. The two heads are fitted below the two sprockets. The head on the left side is designed to erase and wipe the tape clean before recording. The centrally located head functions as the record and playback head and is the one that contains the two tiny electromagnets. The capstan and pinch roller are fitted on the right. The capstan revolves at a precise speed and pulls the tape across the head at the right speed. The standard speed of the capstan is 1.875 inches per second. The function of the pinch roller is simply to apply pressure in order that the tape is held securely and tight against the capstan.
Thanks to the Walkman, portable music has come a long way. Today, the audio cassette tape recorder has been replaced by CD, DVD players and more.