We can assume that in 1979, Sony produced the first portable device in the world capable of playing playback music using magnetic cassettes and headphones. The first Walkman allowed playing music with bad quality recorded on a magnetic cassette. The quality was supervised by numerous audio systems built into the first integrated circuits.
Walkman from sony as a first Portable Audio Player
The use of magnetic tape was associated with loss of quality when copying recorded audio signals. In addition to that, using cassettes only while listening to music meant demagnetization of the audio signal from the cassette or the breaking of magnetic tape itself. A few years later, CD was invented and the first audio discs that could play music with high quality could be found on the market.
Discman
Discman’s main problem was that one CD just stored 80 minutes of music. Next stage gave birth to portable digital music which allowed storing music in memory as digital files. Since then, the number of songs on the device depended on the amount of memory built into the portable player.
MP3 Audio Players
Finally, the sound can also be played by the current smartphone with or without headphones
or with all audio devices that allow you to connect the phone as a signal source.
Smartphone as a Sound Source
