Forensic Audio Engineering gained sudden fame in 1973 during
the "Watergate Scandal"
investigation, when it was revealed that President Nixon had been
making tape recordings of his conversations and phone calls, and
that a gap of 18 and a half minutes had been discovered in the
tape of a conversation between Nixon and Haldeman on 1972 June 20.
In 1973 November, the United States District Court for the district of
Washington, D.C. assigned six technical experts the task of verifying
the integrity and originality of a number of audio tape recordings.
They were directed to focus especially on the 18 minute gap, to
determine how the erasure occurred and whether any of the original
recording could be recovered.
The results of the tests and examinations made by the experts were
prepared in a report that was submitted to the Court and were presented
to the grand jury. They were widely reported on television and in the
press -- see, for instance, "Time",
1974 January 28, pp 13...18. The report was publicly available at
the time, but has long been out of print.
To accomplish their objectives, the experts had to assemble and prove
the effectiveness of a number of different methods for examination of
analog audio tape recordings. An essential requirement was that the
evidence obtained by any one method had to be consistent with those
obtained from the other methods.
The set of techniques that was developed formed the basis of a new
forensic technology, and the report became its textbook. Subsequent to
its publication, the methods described therein have been used widely to
validate the authenticity of tape recordings that were offered into
evidence in numerous civil and criminal court trials. See for instance
"AES43-2000 (r2005): AES
standard for forensic purposes -- Criteria for the authentication
of analog audio tape recordings".
We are pleased to now make the complete report available online. Our
thanks to Tom Fine for making the scans that are the basis for these
PDF files. For convenience in downloading, we have divided the report
into five sections:
This presentation of this on-line version of the report is dedicated to
the memory of three of the technical experts. These are Richard
Bolt, former chairman of Bolt, Beranek, and Newman, who became the
spokesman for the group and contributed greatly to the clear and
logical organization of the report; Franklin Cooper, former president
of Haskins Laboratories, whose patient and genial editing suggestions
helped make sections of the rapidly written report much more readable;
and Tom Stockham, who contributed greatly to the development and
digital audio, and who struggled patiently, albeit unsuccessfully, to
recover fragments of the original recording.
John G (Jay) McKnight, Chair
AES Historical Committee
Mark R Weiss