A personal stereo is a portable audio player using an audiocassette player, battery power and in some cases an AM/FM radio. This allows the user to listen to music through headphones while walking, jogging or relaxing. Personal stereos typically have a belt clip or a shoulder strap so a user can attach the device to a belt or wear it over his or her shoulder. Some personal stereos came with a separate battery case.
The first personal stereo was the Stereobelt invented and patented by West German-Brazilian inventor Andreas Pavel in 1977. Pavel attempted to commercialise this invention but failed to do so.
The first commercial personal stereo was the Sony Walkman released in 1979, created by Akio Morita, Masaru Ibuka (the co-founders of Sony) and Kozo Ohsone. It became a popular and widely imitated consumer item in the 1980s. In the 1990s, portable CD players became the most popular personal stereos. In the 2000s, digital players like the iPod became the dominant personal stereos. During this period, smart phones (advanced cell phones) like the iPhone also became popular music listening devices.