Alesis digital audio tape (ADAT)

16bit / 20bit ADAT 8 track, digital audio recordings on Super VHS tape
black rectangular plastic ADAT cassette - closely resembling S(VHS) video cassette but with text: Quantegy ADAT Master Digital Audio Cassette

ADAT-specific cassette tape

introduction to ADAT transfer

Alesis Digital Audio Tape or ADAT is a magnetic tape format used for the simultaneous digital recording of eight analog audio or digital audio tracks at once onto Super VHS (S-VHS) tape.

At Greatbear, we carefully restore and digitise 16 and 20-bit ADAT 8-track tapes, as well as sessions with higher track counts spanning multiple tapes.

We offer a range of delivery formats for our audio transfers. We use the International Association of Sound & Audiovisual Archives Guidelines on the Production and Preservation of Digital Audio Objects, delivering 24-bit/96kHz Broadcast WAV files, together with mp3 audio file or audio CD listening versions. We're happy to create any other digital audio files, according to your needs.

We can provide the appropriately-sized usb media for your files, or use media supplied by you, or deliver your files online. Files delivered on hard drive can be for any operating system MacOS, Windows or GNU/Linux and filesystems (HFS+, NTFS or EXT3).

Due to varying tape durations and extent of physical tape degradation it’s not always appropriate to create fixed prices for our services. We’ve found that assessing tapes prior to confirming costs is a more accurate and fair method.

We offer free assessments please contact us to discuss your project.

ADAT machines

Like DTRS recorders, ADAT tape recorders use a video tape transport but running at a faster speed. Unfortunately most ADAT machines used a consumer tape transport that was not particularly rugged, often causing tape lacing problems which will damage tape. Only the later M20 and Studer ADAT machines used a much higher-quality transport that lasts well.

The ADAT format was based on a VHS transport, but even so - spares will not be available forever and key spares like the upper and lower head drum, while generally long-lasting will wear and need replacement.

Our ADAT machines include:

  • Alesis ADAT XT
  • Alesis ADAT M20
  • Alesis ADAT LX20


ADAT format variation

tape end view of cassette with protective shell opened to reveal 12.7 mm (½ inch) black magnetic tape

ADAT (S-VHS) open shell: tape width 12.7 mm (½ inch)

2 rack-based Alesis machines with multiple buttons and bar-level display, upper one is gold-coloured and lower one is brushed steel

Alesis LX20 Type II and Alesis XT Type I ADAT machines

Black plastic cassette tape with rulers showing dimensions: 18.7 × 10.2cm (7​1⁄3 × 4 inch)

ADAT (S-VHS) cassette dimensions: 18.7 × 10.2 × 2.5 cm (7​1⁄3 × 4 × 1 inch)

ADAT risks & vulnerabilities

While ADAT machines use standard S-VHS tapes, there are some issues which are specific to this multitrack digital format:

  • The tapes run at around 4 times the standard VHS tape speed, so transports can wear out quickly.
  • While expensive new, most ADAT machines used a transport common to domestic VHS machines, which do not respond well to heavy use.
  • Direct digital transfer is preferable for making transfers, but this can be tricky without specialist hardware - especially when transferring multiple session tapes (16, 24, 32, 48 track sessions)

ADAT recording history

The first ADAT machine was released in 1991 and had a major impact on the recording industry and home recording. Like the DA models released by TASCAM, a major benefit was that they could be synchronised with other machines, allowing for people to build their recording capacity 8 tracks at a time.

ADAT’s use of ½ inch S-VHS video tape meant that the larger tape width was less susceptible to damage than the 8mm Hi8 tapes used by the DA-88 and DTRS. The S-VHS tapes could record 40 minutes and because 8 tracks of audio require a large amount of bandwidth, the tape moved up to three times the speed of the average VHS tape.

ADAT is still used in some industries and the recording industry, even if it has to a large extent been replaced by Digital Audio Workstations (DAWs).

ADAT subsequently referred to the Alesis ADAT HD24-XR, which featured hard disk recording rather than the traditional tape-based ADAT (now considered obsolete), but this machine too has now been discontinued.