Audio Formats: Digital Audio Tapes (DATs), Compact Discs (CDs), MP3 Players

Digital Audio Tapes (DATs) operate on the same principle of recording and reading magnetic media, but the stored data is digital rather than analog. This means that the magnetic signal no longer corresponds directly to the recorded audio but is encoded in a binary-based system that requires a computer to decode and play back. DATs represent a bridge between older methods of magnetic recording and the digital playback of media that rose to prominence starting in the 1980s, with the compact disk (CD) being the last mass market physical media dedicated to audio playback. Unlike recording media which used physical grooves or magnetic tape, CDs store data optically by encoding binary data on indentations on a reflective layer that is read by a laser. Commercial discs that could store around 650 MiB of data, which translated to 74 minutes of audio were first sold in 1982. Once audio went digital, it became divorced from physical media as any device that could read an audio file (e.g. MP3) could be used for playback. While there were many competing digital audio players, the Apple iPod became emblematic of the category after its release in 2001. The shift to MP3s resulted in a decrease in audio quality due to the increased data compression used to reduce file sizes and fit more music in a given storage space.