In the technological age, audio evidence plays a significant role in court. As a result, Primeau Forensics provides forensic audio authentication and analysis for use as admissible evidence during litigation.
WHAT IS AUDIO AUTHENTICATION?
Audio authentication is a form of forensic science used to determine if a file presents accurate, unaltered information. According to the Scientific Working Group on Digital Evidence (SWGDE), the recording should be consistent with how it was supposedly created.
HOW TO AUTHENTICATE AN AUDIO RECORDING
Audio authentication includes a series of steps:
ASSESSMENT
Experts will review an audio file regarding the case and decide if it's worth authenticating and how to proceed.
ACQUISITION
When audio is improperly handled or examined, the evidence can be damaged.
EXAMINATION
Audio experts will perform a series of tests to determine authenticity.
DOCUMENTING AND REPORTING
Technicians compile all substantial evidence and present it as a report.
INTEGRITY TESTING
LISTENING CRITICALLY
When we first receive an audio file, our audio authentication experts will review it closely. This initial listen involves noting audio behaviors such as background noises and voices. For instance, if we notice any unusual sounds or activity, we know what to pay attention to during processing.
ANALYZING METADATA
The metadata — the information embedded in the file — can make critical statements about an audio clip's authenticity. Notably, metadata will reveal the use of any third-party recording and editing software, such as Adobe Audition. This information doesn't confirm editing, but it can be a strong indicator.
DETECTING EDITING
After analyzing the metadata, we'll examine the audio itself to detect any edited audio. Tampering may involve removing sounds or even rearranging sentence structures to change the value of the information.
CREATING AN EXEMPLAR RECORDING
The final stage of integrity testing involves creating another recording with the same method used to create the evidence. Our audio authentication experts will try to recreate recording conditions as closely as possible to the original file. From here, we can compare hexadecimal (HEX) information and metadata to see if they match.
TESTING TIME AND FREQUENCY DOMAIN
Digital audio authenticity also relies on time characteristics and sound frequencies. An audio authentication analysis may involve using an electronic measurement test to look at the start signature or sampling rates. Experts will measure and listen for frequency shifts in background noise, voices and other notable sounds on the recording. The forensic audio analysis investigation can determine if a recording has been laundered through a recorder, or was originally created with the alleged original device.
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