Digital Recordings and the CD

Digital audio began in the telephone industry, where it was used to digitize telephone conversations and, in effect, compress them so that more conversations could be handled on existing lines. Since the bandwidth of a telephone line is very narrow, the sound quality issues were focused on basic intelligibility of speech rather than realism and detail. However, the basic techniques could be applied to high quality recording. The earliest experiments with digital recording of high quality audio were probably those undertaken in Japan in the 1960s. Following the introduction of Betamax VCRs, which used a technology for video similar to what was needed to make digital audio recordings, Sony briefly offered an audio-only Betamax recorder, capable of recording audio digitally. This pioneering effort was largely forgotten by the time digital audio tape was reintroduced in the 1980s.

In the meantime, Phillips and Sony (among others) had been working on ways to record TV signals with a laser onto a reflective disc. As with the Betamax, some of the features of video recording are applicable to digital audio recording, so it was not a great leap from the early, analog laser videodiscs introduced in 1978 and later to the compact audio disc, introduced in 1982-3. The CD was not an immediate hit, and it took nearly a decade for it to displace the audio cassette, but in the 1990s it became the most popular home format. Recordable CDs were not generally available until the mid-1990s, and few were sold before about 2000, when their sales took off. There were numerous variations of the CD and digital tape during the 1990s, few of which survived the decade. Today, the CD is being challenged by the DVD (which is also used for video), but it is unclear whether either of these formats will survive the challenge of media-free audio technologies such as MP3.