There are currently millions of people across the world using DVD’s, CD’s, and downloading and listening to digital audio music. Digital music and digital sound have become a mainstay of our everyday lives. Since the digital revolution started, recording tape and its various incarnations have virtually disappeared from both the professional media world as well the consumer one. Cassette tapes, once the darling of audiophiles, have disappeared as well as reel-to-reel tape players. It is then with some degree of irony that in looking back over the digital audio landscape that the first digital format offered to consumers was, in fact, a tape, not a disc nor a computer file.
Digital Audio Tape (DAT or R-DAT) is a signal recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to an compact audio cassette and used 4mm magnetic tape enclosed in a protective shell. As the name suggests, DAT has the ability to record at higher, equal or lower sampling rates than a CD. 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.
Although intended as a replacement for audio cassette, the format was never widely adopted by consumers because of issues of expense and concerns about unauthorized digital quality copies. The format did see moderate success in professional markets and as a computer storage medium.
The technology of DAT is closely based on that of video recorders, using a rotating head and helical scan to record data. This prevents DAT’s 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 48kHZ at 16 bits. Certain recorders operate outside the specification, allowing recording at 96kHZ and 24 bits( HHS). Since each recording standard uses the same tape, the quality of the sampling has a direct relation to the duration of the recording – 32kHZ at 12 bits will allow six hours of recording onto a three hour tape while HHS will only give 90 minutes from the same 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 fastseeking. 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 was not the first digital audio tape; pulse code modulations or PCM was used in Japan By Denon in 1972 for the mastering and production of analogue phonograph records, using a 2-inch Quadraplex-format videotape recorder for its transport, but this was not developed into a consumer product.
Starting in 1973, 3M introduced its own line and format of digital audio tape recorders for use in a recording studio. One of the first prototypes of 3M’s system was installed in the studios of Sound80 in Minneapolis, Minnesota. This system was used in June 1978 to record Aaron Coplan’s Appalachian Spring by the St. Paul Chamber Orchestra conducted by Dennis Russell Davies. That record was the first grammy-winning digital recording. The production version of The 3M Digital Mastering System was used in 1979 to record the first all-digital rock album, Ry Cooder’s “Bop Till You Drop” , made at Warner Brothers Studio in California.
The DAT recorder mechanism was more complex and expensive than an analogue cassette deck mechanism due to rotary helical scan head. It was to compete with this mechanism that Philips & Panasonic Corporation developed a rival digital tap recorder system with a stationary head based on the analogue compact cassette. The DCC was cheaper and simpler mechanically than DAT, but did not make perfect digital copies. DCC was never a competitor to DAT in recording studios because DAT was already established and it was launched at the same Time as Sony’ Minidisc format which had random access and editing features. Both DAT and Minidisc were unsuccessful with consumers.
In the late 1980’s, the Recording Industry Association of America unsuccessfully lobbied Against the introduction of DAT devices into the U.S. The organization threatened legal action against any manufacturer attempting to sell DAT machines in this country. It also sought to place restrictions on DAT recorders to prevent them from being used to copy LP’s, CD’s, and prerecorded cassettes. One of these efforts, the Digital Audi Recorder Copycode Act of 1987 involved a technology called Copy Code and required DAT machines to include a chip to detect attempts to copy material recorded with a notch filter. This would cause copyrighted material, analog or digital, to be recored with distorted sound. CopyCode was ineffective at preventing copying and the idea was abandoned after Sony, a DAT manufacturer, bought CBS records in January of 1988. In place of CopyCode, Congress passed legislation which Required that DAT recorders have a Serial Copy Management System to prevent Digital copying for more than a single generation. This requirement was enacted as part of the Audio Home Recording Act of 1992 which also imposed taxes on DAT recorders and blank media.
DAT was envisioned by proponents as the successor format to analogue audio cassettes In the way that the compact disc was the successor to vinyl-based recording; however, the Technology was never as commercially popular as CD. DAT recorders have remained relatively expensive and commercial recordings are generally not made available on the format.
DAT was widely used in the professional audio recording industry in the 1990’s, and is still used to some extent. Particularly with regard to archives created in the ’90, although most labels have a program in place to transfer these tapes to a hard disk-based database. DAT is used professionally due to its lossless encoding, which allows a master tape to be created that is secure and does not induce tape noise (hiss) into the recording.
One area where DAT popularity was unexpected was, for a time, with regards to making and
Trading live music recording since available DAT recorders predated affordable CD recorders.
In the U.S., the RIAA and music publishers continued to lobby against DAT, arguing that
consumers’ ability to make perfect digital copies of music would destroy the market for
commercial audio recordings. The opposition to DAT culminated in the passage of the
resulting Audio Home Recording Act of 1992, which, among other things, effectively imposed
a tax on DAT devices and blank media.
In November of 2005, Sony announced that its remaining DAT machine models would be
discontinued the following month. Sony has sold around 660,000 DAT products since its
introduction in 1987. However, the DAT format still finds regular use in film and television
recording due to the support in some recorders of SMPTE time code synchronization.
Related Links:
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