Alesis Digital Audio Tape or ADAT, first introduced in 1991, was used for simultaneously recording eight tracks of digital audio at once, onto Super VHS magnetic tape - a tape format similar to that used by consumer VCRs. Greater numbers of audio tracks can be recorded by synchronizing several ADAT machines together. While this capability had been available in earlier machines, ADAT machines were the first to do so with sample-accurate timing - which in effect allowed a studio owner to purchase a 24 track tape machine eight tracks at a time.

This capability, combined with their relatively low cost (in comparison with other ways af achieving the same effect) enabled the creation of project studios. In addition, these machines pioneered light-pipe interfaces, which transported audio from machine to machine 8 tracks at a time over fiber-optic cables with no signal degradation.

Several versions of these machines were produced. The first generation ADAT machines used 16 bits per sample. A later version was released to support 20 bits per sample. Both machines were capable of recording at a variety of sample rates including the 44.1kHz and 48kHz rates popular in the audio industry.

Today, ADAT is simply a format for transport of (up to) eight tracks of digital audio at once. The format is no longer strictly tied to ADAT tape machines, and is utilized by AD converters, input cards to DAWs, effects machines, etc. One of the benifits of utilizing ADAT versus S/PDIF or AES/EBU is that a single cable can carry up to eight inputs, or tracks. Thus, a user can save eight tracks at a time with one ADAT computer interface.

ADAT is considered a professional format, and while it is slowly being replaced by the computer-based DAW, it is still a format widely used in the recording industry. Because of its high reliability, it is also still in use for scientific work, and to drive laser light shows.

See also

• Digital Audio Tape