Could the President's Tapes Be Altered?

Since President Nixon agreed to hand over the Watergate tapes, a consuming question in Washington has been whether tapes can be altered without detection. The answer is a qualified yes. The right man with enough time and with access to the original tape recorder could, in the opinion of audio experts, make substantial changes that would defy detection.

There is no reason to assume that the Watergate tapes have been tampered with; that would be a major undertaking. Most experts believe that the necessary know-how could not be found in the U.S. Government, not even among the engineers of the Army Strategic Communications Command. Such skills are scarce even outside Government. Estimates of the number of people able to accomplish the task range from half a dozen to 1,000. Moreover, not even a qualified man with the nerve and skill of the Jackal would be enough. He would also have to be willing to leave himself open to criminal charges of tampering with evidence. "Whoever would do that would have to be crazy," says Mortimer Goldberg, technical operations supervisor at CBS Radio. In an Administration where apparently no skulduggery has been safe from exposure, it is more than likely that sooner or later the man's name would be leaked.

All an expert would need in the way of equipment to alter tapes would be a recording studio, two to four quality tape recorders, a variety of auxiliary gadgets and perhaps an echo chamber. First he would listen to the tape over and over again until he felt at home with the speech patterns--voice modulation as well as breathing space. When he was satisfied that he knew the voices as well as his own, he would do the easy part first--simply cutting out certain words or sentences with a razor blade and splicing the tapes together. This would probably constitute the bulk of his work. From there he would move on to the more complicated tasks: rearranging passages, constructing new words out of word fragments.

Once the tape was recomposed, he would have to make sure that it flowed smoothly from beginning to end, with no telltale shift in tone of voice. Inflections can now be modified with a device known as a variable-speed constant-pitch tape recorder. "When we increased the speed in the past," says Goldberg, "we increased the pitch too. The voice sounded like Donald Duck's. Now we can pick up or slow down without changing the pitch." Background noise can be simulated by playing a second tape behind the voice tape. Thus, if in the original tapes, doors are slamming, buzzers buzzing, asthmatics wheezing or pipes clinking against ashtrays, all of these sounds can be perfectly duplicated. Such background noises can be used to blur over any foreign sounds caused during the editing of a tape. Says Goldberg: "This kind of masking covers a multitude of sins."

When the tape is completed, it is recorded on another, unspliced tape. This is done on the original machine, since each recorder leaves its particular markings on tapes. As exacting as open-heart surgery, the process of altering a tape is extremely timeconsuming. It may take as long as an hour to change a word; to alter a one-hour tape could consume a full day. The result of all this fastidious enterprise can be startling. A record is available of one of Nixon's speeches defending his role in Watergate; on the flip side is a doctored version of the speech in which Nixon confesses that he was to blame for Watergate. Same speech, same words--only differently arranged.

Aware of these doctoring techniques, Judge John J. Sirica has indicated that he would like experts to examine the Watergate tapes. But there is a problem; anyone who listens to the tapes will learn what is on them--a breach of confidentiality. Under the U.S. Court of Appeals order, only Sirica is supposed to hear the tapes initially. Even if Sirica wins authorization to have the tapes examined, the fact remains that the technology of detection is not so far advanced as the technology of deception.* The detector must rely on an oscilloscope, which translates electrical impulses of sound into visual patterns --green wavy lines--on a screen. These patterns are altered by erasures or breaks in a tape. But a skillful masking job does not interrupt the pattern and leaves the impression that no editing has been done.

Though some audio experts believe that they can uncover almost any kind of tampering, the hard evidence seems to dispute this. Last August the Canadian Broadcasting Corp. put on a radio show in which nine audio specialists were asked to identify parts of a tape that had been doctored. They were unable to detect 90% of the edits--but reported finding numerous nonexistent changes. Producer Max Allen explained: "In a speech by Roy Cohn [Joe McCarthy's onetime protege], they said they had looked at their oscilloscopes and swore they saw edits. But it was just Cohn's pattern of speech, which sounded naturally as if it had been edited."

At the program's end, all the participants agreed that they would never be willing to testify in court on whether a tape had been doctored or not.

* Sirica will have no difficulty identifying the voices on the tapes, since the White House is supplying him with a log indicating the participants at each of the meetings, which were usually attended by only a few persons.

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