Archivists Warn: Don't Depend on DAT
In recent years film and video makers
have embraced the DAT audio format as a convenient and economical way to
record and store high-quality location audio. Now some of the worlds
leading audio preservationists are warning that tape-based digital recording
media especially DAT is not reliable for long-term archiving of
During a recent AES panel discussion on digital
the archivists urged recording equipment manufacturers to quickly create
reliable long-term storage media for analog and digital audio recordings.
There was a consensus that, at least for now, analog tape is the only
proven, reliable way to preserve sound recordings for the future.
Ironically, one of the most passionate pleas came from Marc Kirkeby, senior
director of the American music archives for Sony, a company that is not only
a leading manufacturer of digital recording equipment and media, but the
owner of more than 600.00 recordings dating back to the turn of the century.
"The potential for disaster out there cannot be overemphasized,"
said Kirkeby, who noted that most valuable recordings are retrievable today
only through blind luck. " We have tapes from 1949 that sound
wonderful," he said. "We have tapes from 1989 that are shot to
hell. And its all just chance."
Kirkeby said that now, 15 years into the digital recording era, "it is painfully apparent that there has not been a digital medium
introduced that really serves an archival purpose. If you have to go to bed
at night wondering if your tapes are going to be there in the morning, thats
not an archival medium."
Sony Music, like most other record companies, has no systematic program to
preserve aging master recordings, Kirkeby said.
"We archive to analog on as-needed basis and we archive
digital-to-digital," he said.
DAT cassettes, said Kirkeby, are especially unpredictable in their
reliability. He said hed bet his pay that analog originals will outlive DATs. "Theres always that little moment when you
put the thing in the machine," he said. "Is it going to play or
If you knew that outside of 10 years certain chemistry aspects would start to
change, then you could allow for that. But, if youcant predict it, how do you plan? Thats my problem with DAT."
Though there were no location sound recordists for film or television on the
panel, all the participants use the same equipment and techniques that are employed on visual
productions. Virtually all of the panelists cited problems with the DAT
format as an archival medium.
DAT was criticized by John Barnes, a European specialist in operatic
archival recording who has used the format at the Glynbebourne Festival Opera in
England. "Weve had very bad experience with DAT tapes and, in particular, DAT housings," he said, estimating that he finds an average of one malfuncti- oning DAT
tape out of every 20 he uses.
"Im not at all happy about the use of DAT tape as a long-term
storage medium and weve got to try to find an alternative," he said.
"(There are) far too many failed masters and failed copies using
so-called high quality professional grade DAT tapes."
DAT was also maligned by Gerry Gibson, a specialist in electronic media
preservation at the Library of Congress andchairman of the AES Audio Preservation Standards Group.
"We believe that long-term preservation of audio will be digital,"
said Gibson. "For now, however, our experience is the current digital
media and systems are not appropriate for long-term storage or preservation.
For preservation, said Gibson, the Library of Congress - the largest
information collector in the world depends on half- track, quarter inch
analog audio tape for backing up its over three million sound recordings.
"Further, we are very leery of any compression schemes for the
long-term storage of preservation masters because of fear that compression
means loss of information regardless of how good the algorithm is", he said. "I
have reservations, as an archivist and a historian, that I can really rely
upon that machine to make the decision as to whats not useful data."
Veteran recording engineer Roger Nichols, who said hes a regular user of DAT himself, warned recordists to treat the
digital cassette format as a temporary medium. "Where in archival you
are worried about longevity, the DAT tape isnt quite going to make
it," he said. "As for a medium for temporarily storing your data,
its (acceptable for) a year or so, but you will eventually transfer (the
data) to something else."
Alignment of DAT machines is a major reason for the problems, Nichols said.
"If you look at a DAT alignment tape on a machine, theres a DAT
standard of plus or minus 10 percent," he said.
"You (use) one machine thats 10 percent one way within the DAT
standard and you want to play back on another machine that ten percent the other way, but its not going to (work). I run
into problems all the time with DAT compatibility."
As for alternative digital storage media for preservation, several panelists
said they are currently investigating alternative possibilities. The recordable CD format CD-R is most promising so
far, they said.
"We tried CD-R for the first time this year and have been very happy
with it," said Barnes. "The only problem at the moment is
recording length. Seventy-four minutes is too short. We need something in
excess of 120 minutes."
Audio recordists, said Sonys Kirkeby, need desperately to get beyond
their dependence on "the medium of the moment" and find a digital
audio backup system that offers long-term stability".
MIX Magazine. August 1996.
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