ADAT

Click image for larger photo

Alesis Digital Audio Tape is a digital tape format intended for music recordings. ADAT-recorders use VHS video cassettes. The manufacturers recommend good quality Super VHS tape.

The ADAT was introduced in 1991 and some people still use the format. One cassette can record eight tracks, but the number of tracks can be increased up to 128 tracks by adding recorders. The recorders are synchronized at sample accuracy.

The first ADAT recorders used 16 bit bitrate and 48 kHz sampling rate. It was possible to use 44,1 kHz by slowing the tape down with the varispeed. Later recorder models had also 20 bit bitrate and the 44,1 kHz sampling rate.

The cassette runs at a higher speed in the ADAT than in a video recorder. This is why the cassette duration is smaller than what it says on the tin. A 120 minute cassette records 40 minutes of audio in an ADAT recorder.