"Watergate" and Forensic Audio Engineering

 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:

The main Report (4.8 MB), and
Technical Notes 1 and 2 (3.0 MB),
Technical Note 3 (4.9 MB),
Technical Notes 4...7 (4.3 MB), and
Technical Notes 8...13 (2.0 MB).

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 application of 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


AES - Audio Engineering Society