ADATs

ADATs, or Alesis Digital Audio Tape, is a digital audio recording format introduced in 1992 by Alesis, designed to provide affordable multitrack recording using standard consumer-grade tapes. A single ADAT tape can hold eight channels of digital audio, typically 16-bit PCM at 44.1 or 48 kHz, across a single pass. The data are recorded on a standard S-VHS 8 mm tape using a helical-scan mechanism rather than a linear method. The format gained popularity in home and project studios for its combination of inexpensive media, modularity, and compatibility with professional mixers.

The ADAT format is complemented by the ADAT Lightpipe interface, a fiber-optic (Toslink) connection that carries the eight digital audio channels between devices. Lightpipe supports eight-channel 16- or 24-bit PCM at 44.1 or 48 kHz, and, through a technique called SMUX (high-speed multiplexing), can transport higher sampling rates such as 88.2 or 96 kHz by interleaving channels. The ADAT ecosystem included multiple recorders and machines from Alesis and other manufacturers, enabling synchronous multitrack recording with relatively low cost.

With the rise of hard-disk recording and integrated digital interfaces, use of ADAT tapes declined after the late 2000s, though the Lightpipe interface remains common in audio gear as a digital I/O standard. Some devices continue to support ADAT as a means to expand channel counts in studios.