digital audio tape (DAT)

Digital Audio Tape (DAT) recorded at 48, 44.1 or 32kHz and at 16-bit or 24-bit resolution
bright purple rectangular DAT cassette, inscribed: For Professional Audio Applications

HHB DAT cassette

introduction to DAT transfer

Digital Audio Tape aka DAT or R-DAT, was used professionally by the audio and recording industry in the 1990s as part of an emerging all-digital production chain.

At Greatbear, we carefully restore and digitise all types of content recorded to DAT, and can support all sample rate and bit depth variations.

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 a more accurate and fair method.

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

DAT machines

We use Sony PCM 7030 / 7040, Fostex and Tascam DAT machines. The PCM 7030 has probably one of the best transports of any DAT machine built and is one of the more serviceable machines made. This is important as DAT as a format for recording is now obsolete yet there are many, many DAT tapes surviving and the machines, if not looked after, are slowly decaying!

DAT is an early digital tape format and essentially it is a video format adapted to record audio. Its longevity is similar to any video tape because the rotary head system used to record and read the tape is subject to degradation and specialist tools are needed to fix the playback machines effectively.

The problem of acquiring the relevant spare parts to keep DAT machines working, like many of the machines we use, is also an issue because spares are no longer manufactured.

Almost all DAT machines could only record at 48, 44.1 or 32 kHz and at 16-bit resolution. A few later machines could record at 24-bit depth too, which we can support.

DAT format variation

tape sample rate in kilohertz (kHz)tape bit depthdigital transfer supportedanalogue transfer supportedtape timecode capture supported
3216
44.116
44.124
4816
4824
view from tape end of purple cassette shell, showing black magnetic tape

DAT shell open: tape width 3.81mm / 0.15"

enlarged image shows 4 rack-based professional tape machines with multiple buttons, dials and digital displays

Tascam DA-45HR, Tascam DA-60 MKII, Sony PCM 7040, Sony PCM 7030 and Fostex D-5 DAT machines

bright purple rectangular DAT cassette, with rulers showing dimensions 7.3 cm × 5.4 cm

DAT cassette dimensions: 7.3 cm × 5.4 cm × 1.05 cm

DAT risks & vulnerabilities

At 3.81mm wide and 0.013mm thick, Digital Audio Tape is fragile compared to other cassette-based digital and analogue formats. With well-preserved tape, and DAT transports that are correctly aligned and not worn, this format can still be reliably replayed, transferred and sound excellent.

The problems arise when the tape has become damaged or contaminated, for example with mould growth. Even a small crease or crinkle to the tape can cause significant problems often resulting in audio mutes where the machine's error-correction system cannot correct. Due to the slow linear tape speed of DAT (just under 1 cm/s), several seconds of unrecoverable errors can result from a small section of damaged tape.

Mould growth, even on a small scale, can be catastrophic, sticking one edge of the tape pack together so when wound or played the tape will rip and result in significant recording loss. See: Mouldy Tape

Based on a miniature video transport, DAT uses a helical scan recording system and therefore cannot be spliced for clean edits. Splices also risk irreparable damage to heads on the drum. A safer solution is to rehouse each spool in another shell.

There are reports of sticky shed syndrome (SSS) in some brands of DAT.

 

DAT recording history

DAT was developed by Sony and introduced in 1987. DAT’s proponents envisaged the format to supersede audio cassettes, but it didn't become commercially successful outside Japan. Machines were expensive and few pre-recorded tapes were made available, limiting its widespread appeal.

The technology of DAT is closely based on that of video recorders, using a rotating head and helical scan to record data (hence DAT is sometimes called R-DAT or Rotating-head Digital Audio Tape). This prevents DATs from being physically edited in the cut-and-splice manner of analog tapes, or open-reel digital tapes.

DAT cassettes are between 15 and 180 minutes in length, a 120-minute tape being 60 meters in length. Tapes longer than 60 meters tend to be problematic in DAT recorders due to the thinner media. DAT machines running at 48 kHz and 44.1 kHz sample rates transport the tape at 8.15 mm/s. DAT machines running at 32 kHz sample rate transport the tape at 4.075 mm/s.

DAT was also used for digital storage because it could store 1.3-80 GB.

In 2005 Sony announced that the remaining models would be discontinued.