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A Government tapes expert consulted by TIME believes that there was such an alteration. This expert, who has done considerable bugging, wiretapping and taping for the Government, also raises the possibility that the tape submitted to the court might not be the original recording but a copy. It might have been made in a bungled attempt to alter and then splice parts of the initial tape. To this expert, the telltale sign is the series of clicks during the hum. Clicks, he reports, are produced when unskilled tamperers try to cut and splice tape. The buzzing sound then might even have been introduced to try to conceal the earlier attempt at deception.
Sirica has asked a panel of experts to examine the tapes. Selected by both the White House and the prosecutors, the panel includes some of the nation's most sophisticated sound and recording experts.* Last week the controversial June 20 tape reel was carried to New York City in a steel box to prevent any possible interference by magnetic fields. Six fully armed U.S. marshals escorted it on a train. It will be examined at the laboratories of the Federal Scientific Corp. in West Harlem. Also transported were the Uher tape recorder and Miss Woods' Tensor lamp and electric typewriter. The experts, who are expected to present preliminary findings to Sirica within two weeks, almost certainly will be able to determine whether Miss Woods' office equipment was capable of producing all or part of the recorded noise.
Some other experts consulted by TIME are confident that the skills of scientists in detecting tape alterations run well ahead of the talents of all but the most ingenious tamperers. Particularly through the use of spectral analysis techniques, in which various sound frequencies on a tape can be separated and studied, these experts believe that any heavy handed deception can be exposed.
One group of scientists at the University of Arkansas reports in a paper that "any alteration of the White House tapes could be detected in a timely fashion." The ear can be fooled and so can the oscilloscope (a device that can depict sound waves as electronically-generated graphs). But the spectral analysis may well determine whether a given recorder produced a specific recording, whether a tape has been cut or edited, whether it is an original or a copy. Any change in microphones or acoustical conditions would be suspect. Since a recorder gradually heats up as it plays, any sudden shift in temperature leaves a magnetic pattern on tape that might tip off an analyst to tampering.
Nail Down. Physicist Alan V. Larson, who helped write the Arkansas paper, insists that the panel of experts will be able to either "verify or challenge" Miss Woods' version of what happened. "They'll nail her right down," he predicts. Other experts are not so certain. Kenneth Stevens, a professor at M.I.T., agrees that "an amateurish" tampering job could be readily detected, but he is not sure that the panel will be able to say with certainty whether a specific tape has been altered.
The scientists widely suggest that the White House could help considerably by turning over a random sampling of a dozen or so of its other secret tapes for