NBC News is reporting that the audio recordings of radio transmissions between pilots of the missing Malaysian jet and air traffic controllers were “edited” before they were made public.

Malaysian Airlines tapes

Tapes “appear to be recorded by two different audio sources”

Citing voice experts, NBC news reports the tapes “appear to be recorded by at least two different audio sources, one of which may have been a digital recorder held up to a speaker.”

The brevity of the interactions between the cockpit and controllers made it impossible to glean any information about the pilots’ state of mind before the plane disappeared, the report says, or even to determine whether both the pilot and co-pilot were speaking or if just one can be heard.

No background noise at issue

Analysts who listened to the recordings for NBC News discovered at least four clear breaks in the audio indicating editing.  “It’s very strange,” audio-video forensic expert Ed Primeau was quoted as saying.  Primeau said the beginning and end of the recording are high-quality with a “low noise floor” where ambient background noise is almost silent.  The middle of the audio does have floor noise, the report said.

“At approximately 1:14 (a minute, 14 seconds into the audio, which can be heard here), the tone of the recording change to where to me, it sounds like someone is holding a digital recorder up to a speaker, so it’s a microphone-to-speaker transfer of that information. That’s a pretty big deal because it raises the first red flag about there possibly being some editing,” he said.

Blame on Malaysian authorities for editing tape

Forensic audio examiner Kent Gibson with Forensic Audio in Los Angeles said it looks as though additional edits at 2:11 and 5:08 took place.  He concurred that it sounded as though the middle section was recorded with a microphone near a speaker. “Malaysian authorities or whoever presented (the tapes) made edits for whatever reason.” He added that “it’s not the way to handle evidence,” but it also doesn’t necessarily imply anything about the investigation. “Unfortunately, there are no smoking guns, except there are edits. And there are clear edits,” Gibson told NBC.

The audio recordings, which were published Thursday for the first time as part of a preliminary report by Malaysian authorities, cast dispersion on the lone pilot taking the plan theory, but investigators were quick not to question the investigation.