Digital Audio Tape (DAT)

Digital Audio Tape (DAT) is a recordable digital audio format. It was introduced in 1987 by Sony and looks similar to compact cassettes, but is smaller in size. Used primarily for playing and recording audio and intended as a replacement for analog audio compact cassettes, Digital Audio Tape was not widely popular or adopted by consumers, as most commercial recordings were not available in the format and concerns arose such as unauthorized high-quality copies. Digital Audio Tape saw moderate acceptance as a computer storage medium and in certain professional markets.

Digital Audio Tape has the capability to record at lower, equal or higher sampling rates compared to a compact disc. Unlike an analog audio cassette, a Digital Audio Tape can only be recorded and played in one direction. Similar to video recorders, DAT made use of a helical scan and rotating heads to record data. Real-time conversion is required for Digital Audio Tape when moving to hard disk from the tape. Largely dependent on the machine and tape used, Digital Audio Tape allowed four unique sampling modes, namely:

• 32KHz at 12 bits on 2 tracks
• 32KHz at 16 bits in 2/4 tracks
• 44.1 & 48 KHz at 16 bits in 2 tracks

Newer recording machines were able to extend the bit rates and bandwidths. All modes support two-channel stereo recording. Unlike analog audio tape, Digital Audio Tape records the analog audio wavelength and converts it into its numeric equivalent for playback and storage.

Most digital audio machines had the ability to show the error correction for tapes. DAT was popular in recording studios and were largely used in archives in the late 1980s and 1990s thanks to their lossless encoding. Digital Audio Tape was considered as alternative to VHS tape, optical disc and digital data storage. The low cost and compact size of DAT compared to other methods were its strengths.

Unreliability was one of the major drawbacks of the Digital Audio Tape. Compared to hard disk recording, Digital Audio Tape recording is limited in nature. As Digital Audio Tape recording makes use of an uncompressed digital format, clones can be created from any Digital Audio Tape.

With the advent of CD recorders, MiniDisc and other newer technologies, the DAT format came to be considered obsolete.