Digital Audio Tape

A 90-minute DAT cartridge, size compared to a AA (LR6) battery.
Media type:	Magnetic Tape
Capacity:	120 minutes
Read mechanism:	Rotating head
Write mechanism:	Rotating head and helical scan
Developed by:	Sony
Usage:	Audio storage

Digital Audio Tape (DAT or R-DAT) is a signal recording and playback medium developed by Sony in the mid 1980s. In appearance it is similar to a compact audio cassette, using 4 mm magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. As the name suggests the recording is digital rather than analog, DAT converting and recording at higher, equal or lower sampling rates than a CD (48, 44.1 or 32 kHz sampling rate, and 16 bits quantization). If a digital source is copied then the DAT will produce an exact clone, unlike other digital media such as Digital Compact Cassette or non-Hi-MD MiniDisc, both of which use lossy data compression. The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. ... Image File history File links DAT_logo. ... Image File history File links Download high resolution version (1200x1000, 313 KB) A 90-minute Digital Audio Tape cartridge, size compared to an AAA(LR03) battery. ... Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ... Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... The 1980s refers to the years from 1980 to 1989. ... Typical 60-minute Compact Cassette. ... Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ... For other uses, see Digital (disambiguation). ... An analog or analogue signal is any continuously variable signal. ... “CD” redirects here. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... The sampling frequency or sampling rate defines the number of samples per second taken from a continuous signal to make a discrete signal. ... BIT is an acronym for: Bannari amman Institute of Technology Bangalore Institute of Technology Beijing Institute of Technology Benzisothiazolinone Bilateral Investment Treaty Bhilai Institute of Technology - Durg Birla Institute of Technology - Mesra Battles in Time (Doctor Who magazine) BIT International College, formerly the Bohol Institute of Technology in Bohol, Philippines... In sound processing, quantization is the process of aligning a set of musical notes to conform to a grid. ... Digital Compact Cassette (DCC) was a short-lived magnetic tape sound recording format introduced by Philips and Matsushita in late 1992. ... See also IBMs VM operating system family, where minidisk refers to a logical unit of storage. ... Audio compression is a form of data compression designed to reduce the size of audio files. ...

Like most formats of videocassette, a DAT cassette may only be recorded on one side, unlike an analog compact audio cassette. The video cassette recorder (or VCR, less popularly video tape recorder) is a type of video tape recorder that uses removable cassettes containing magnetic tape to record audio and video from a television broadcast so it can be played back later. ... Typical 60-minute Compact Cassette. ...

History

Development

The technology of DAT is closely based on that of video recorders, using a rotating head and helical scan to record data. This prevents DATs from being physically edited in the cut-and-splice manner of analog tapes, or open-reel digital tapes like ProDigi or DASH. The DAT standard allows for four sampling modes: 32 kHz at 12 bits, and 32 kHz, 44.1 kHz or 48 kHz at 16 bits. Certain recorders operate outside the specification, allowing recording at 96 kHz and 24 bits (HHS). Some machines aimed at the domestic market did not operate at 44.1 kHz when recording from analog sources. Since each recording standard uses the same tape, the quality of the sampling has a direct relation to the duration of the recording – 32 kHz at 12 bits will allow six hours of recording onto a three hour tape while HHS will only give 90 minutes from a three hour tape. Included in the signal data are subcodes to indicate the start and end of tracks or to skip a section entirely; this allows for indexing and fast seeking. Two-channel stereo recording is supported under all sampling rates and bit depths, but the R-DAT standard does support 4-channel recording at 32 kHz. DAT tapes are between 15 and 180 minutes in length, a 120-minute tape being 60 meters in length. DAT tapes longer than 60 meters tend to be problematic in DAT recorders due to the thinner media. Internal Links Related to Video recorder Digital video recorder Video tape recorder Videocassette recorder Video Recordings Act 1984 ... The head drum of a Hi-Fi NTSC VHS VCR; three of the six heads face the reader. ... Editing is the process of preparing language, images, or sound for presentation through correction, condensation, organization, and other modifications. ... Splice has several meanings: In outdoor recreation (such as sailing or camping) rope splicing involves joining two pieces of rope or wire by weaving the strands of each into the other. ... Mitsubishis ProDigi is a professional audio, reel-to-reel, digital audio tape format with a stationary head position, similar to Sonys Digital Audio Stationary Head, which competed against ProDigi when the format was available in the mid 1980s through the early 1990s. ... The Digital Audio Stationary Head or DASH standard was a digital audio tape format using open reels capable of recording 8, 16, 24 or more channels of audio on a one-inch or half-inch tape. ... Label for 2. ... The sampling frequency or sampling rate defines the number of samples per second taken from a continuous signal to make a discrete signal. ...

Predecessor formats

DAT was not the first digital audio tape; pulse-code modulation (PCM) was used in Japan to produce analogue phonograph records in the early 1970s, using a videotape recorder for its transport, but this was not developed into a consumer product. Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code. ... Manufacturers put records inside protective and decorative cardboard jackets and an inner paper sleeve to protect the grooves from dust and scratches. ... The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... A consumer product is generally any tangible personal property for sale and that is used for personal, family, or household purposes. ...

Later in 1976, the first commercially successful digital audio tape format was developed by Soundstream, using 1" (2.54 cm) wide reel-to-reel tape loaded on an instrumentation recorder manufactured by Honeywell acting as a transport, which in turn was connected to outboard digital audio encoding and decoding hardware of Soundstream's own design. Several major record labels like RCA and Telarc used Soundstream's system to record some of the first commercially-released digital audio recordings. Soundstream Inc. ... A Sony TC-630 reel-to-reel recorder, once a common household object. ... For other uses, see Instrumentation (disambiguation). ... Honeywell Heating Specialties Company Stock Certificate dated 1924 signed by Mark C. Honeywell - courtesy of Scripophily. ... RCA, formerly an acronym for the Radio Corporation of America, is now a trademark owned by Thomson SA through RCA Trademark Management S.A., a company owned by Thomson. ... Telarc International Corporation is a Cleveland, Ohio based independent record label, founded in 1977 by two classically trained musicians and former teachers, Jack Renner and Robert Woods. ...

Soon after Soundstream, 3M starting in 1978 introduced their own line (and format) of digital audio tape recorders for use in a recording studio, notably the model M79, with one of the first prototypes being installed in the studios of Sound 80 in Minneapolis, Minnesota. 3M Company (NYSE: MMM), formerly Minnesota Mining and Manufacturing Company until 2002, is an American corporation with a worldwide presence. ... Year 1978 (MCMLXXVIII) was a common year starting on Sunday (link displays the 1978 Gregorian calendar). ... A recording studio is a facility for sound recording. ... Sound 80 was a recording studio in Minneapolis, Minnesota founded by Tom Jung and Herb Pilhofer in 1969. ... “Minneapolis” redirects here. ...

Professional systems using a PCM adaptor, which digitized an analog audio signal and then encoded this resulting digital stream into an analog video signal so that a conventional VCR could be used as a storage medium, were also common as mastering formats starting in the late 1970s. High-quality PCM audio requires a significantly larger bandwidth than a regular FM audio signal. ...

dbx, Inc.'s Model 700 system, notable for using high sample-rate delta-sigma modulation (similar to modern Super Audio CDs) rather than PCM, and Decca's PCM system in the 1970s [1] (using a videotape recorder manufactured by IVC for a transport), are two more examples. dbx, Inc. ... The dbx Model 700 Digital Audio Processor was a professional audio ADC/DAC combination unit, which digitized a stereo analog audio input into a bitstream, which was then encoded and encapsulated in an analog composite video signal, for recording to tape using a VCR. Unlike other similar pieces of equipment... Super Audio CD (SACD) is a read-only optical audio disc format aimed at providing much higher fidelity digital audio reproduction than the compact disc. ... PCM is an initialism which can have different meanings: Phase Change Material Pulse-code modulation, a way to digitally encode signals representing sound and their video counterparts Potential Cancer Marker Communist Party of Mexico Plug Compatible Manufacturer Power-train control module, a computer in a car which controls the car... IVC was a company that manufactured several models of low to middle-end videotape recorders, or VTRs, for industrial and professional use. ...

Mitsubishi's X-80 digital recorder was another 6.4 mm (1/4") open reel digital mastering format that used a very unusual sampling rate of 50.4 kHz. For information on Mitsubishi brand computer monitors, see NEC-Mitsubishi Electronics Display of America Inc. ... Open-reel tape recorders were the first high-quality method of recording audio. ... Audio mastering is the process of preparing and transfering recorded audio to a medium for future duplication. ...

For high-quality studio recording, effectively all of these formats were made obsolete in the early 1980s by two competing reel-to-reel formats with stationary heads: Sony's DASH format and Mitsubishi's continuation of the X-80 recorder, which was improved upon to become the ProDigi format. (In fact, the first ProDigi-format recorder, the Mitsubishi X-86, was playback-compatible with tapes recorded on an X-80.) Both of these formats remained popular as an analog alternative until the early 1990s, when hard disk recorders rendered them obsolete. For the audio technology, see Reel-to-reel audio tape recording Reel to Reel is the debut album by Grand Puba. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... The Digital Audio Stationary Head or DASH standard was a digital audio tape format using open reels capable of recording 8, 16, 24 or more channels of audio on a one-inch or half-inch tape. ... For information on Mitsubishi brand computer monitors, see NEC-Mitsubishi Electronics Display of America Inc. ... Mitsubishis ProDigi is a professional audio, reel-to-reel, digital audio tape format with a stationary head position, similar to Sonys Digital Audio Stationary Head, which competed against ProDigi when the format was available in the mid 1980s through the early 1990s. ...

Uses of DAT

Computer data storage medium

The format was designed for audio use, but through the ISO Digital Data Storage standard it has been adopted for general data storage, storing from 1.3 to 72 GB on a 60 to 170 meter tape depending on the standard and compression. It is, naturally, sequential-access media and is commonly used for backups. Due to the higher requirements for capacity and integrity in data backups, a computer-grade DAT was introduced, called DDS (Digital Data Storage). Although functionally similar to audio DATs, only a few DDS and DAT drives (in particular, those manufactured by Archive for SGI workstations [2]) are capable of reading the audio data from a DAT cassette. Unfortunately, SGI DDS4 drives no longer have audio support. SGI have removed the feature due to "lack of demand" [3]. Digital Data Storage (DDS) is a format for storing and backing up computer data on magnetic tape that evolved from Digital Audio Tape (DAT) technology, which was originally created for CD-quality audio recording. ... For other uses of Backup, see Backup (disambiguation). ...

Home use

Modern DAT has not been very popular outside of professional and semi-professional music artists. However, the prospect of perfect digital copies of copyrighted material prompted the lobbying of the US government by the music industry which resulted in the passage of the Audio Home Recording Act of 1992, the so-called DAT Tax. The inclusion of the Serial Copy Management System in DAT recorders, to prevent digital copying for more than a single generation, was another response. Flaws on the tape or heads can cause the signal to mute briefly on playback, which can be frustrating when attempting to copy material. DAT format was initially quite popular for trading recordings of live music, as available DAT players predated affordable CD recorders. DAT was envisaged as the successor format to analogue audio cassettes in the way that the compact disc was the successor to vinyl-based recordings; however, the technology was never as commercially popular as CD. DAT was introduced in Third World countries, which still make good use of audio cassettes, but it is now cheaper to use CD and CDR. The Audio Home Recording Act of 1992 (AHRA) amended the United States copyright law by adding chapter 10 Digital Audio Recording Devices and Media. ... Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ... The Serial Copy Management System or SCMS was created in response to the digital audio tape (DAT) invention, in order to prevent DAT recorders from making second-generation or serial copies. ... For the Jamaican reggae band, see Third World (band). ...

Future of DAT

In November 2005 Sony announced that the final DAT machines would be discontinued in December 2005.[4] However, the DAT format still finds regular use in film and television recording, principally due to the support in some recorders for SMPTE time code synchronization, although it is slowly being superseded by modern hard disk recording equipment which offers much more flexibility and storage. In 2004, Sony introduced the Hi-MD Walkman with the ability to record in linear PCM. Hi-MD has found some favour as a disc-based DAT alternative for field recordings and general portable playback. This article is about motion pictures. ... SMPTE timecode is a set of cooperating standards to label individual frames of video or film with a timecode defined by the Society of Motion Picture and Television Engineers. ... Typical hard drives of the mid-1990s. ... See also IBMs VM operating system family, where minidisk refers to a logical unit of storage. ...

Archived audio problem

The discontinuation of DAT replayer production leads to a significant problem regarding audio archives, since a tremendous amount of recordings from the mid-80's until ~2000 exist solely on DATs. This means that this material is locked up on these tapes.

Even if some bigger broadcasting stations or studios still have some of them in their internal stock or could find a handful of 2nd hand models, one must consider that each device suffers wearout (play heads, winding mechanism, etc...) that should not be underestimated. Caution: this is a very serious problem.

See also

• ADAT
• Magnetic Tape
• PCM adaptor
• Digital Audio Stationary Head
• ProDigi

This is an article about the digital recording format. ... Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ... High-quality PCM audio requires a significantly larger bandwidth than a regular FM audio signal. ... The Digital Audio Stationary Head or DASH standard was a digital audio tape format using open reels capable of recording 8, 16, 24 or more channels of audio on a one-inch or half-inch tape. ... Mitsubishis ProDigi is a professional audio, reel-to-reel, digital audio tape format with a stationary head position, similar to Sonys Digital Audio Stationary Head, which competed against ProDigi when the format was available in the mid 1980s through the early 1990s. ...

Audio/video

• Digital Compact Cassette (DCC)
• Compact Disc (CD)
• MiniDisc (MD)
• Digital Versatile Disc (DVD)
• Universal Media Disc (UMD)
• Super Audio CD (SACD)