Audio forensics is a branch of forensic science that involves close analysis of audio files. After acquiring a file, audio forensic experts work through a series of stages to confirm the recording’s quality and understand its contents. The examination involves practices such as transcribing dialogue, improving speech clarity, and reconstructing event timelines based on the information presented.



Once an expert examines an audio file, it’s typically used as admissible evidence in a court of law. An audio forensic analysis can be significant in court, whether as a part of a simple civil case or criminal investigation.


The Scientific Working Group on Digital Evidence (SWGDE) established acceptable means of acquiring audio files for scientific analysis. These methods include:


  • Chain of custody: The chain of custody questions the source of the evidence and how it was handled from creation to courtroom delivery. Law enforcement may keep documentation of handling, which helps to confirm the file’s integrity. An expert must document their retrieval of a file to maintain consistency in the chain of custody.
  • Request original: If the chain of custody can’t be identified for authentication, an expert may request the original copy, or the earliest version available. While copies of analog files are never exact, copies of digital files offer the same authenticity as the original file.
  • Acceptable retrieval: When an expert wants to retrieve a file, they have to use a method that preserves the file in a condition as close to the original as possible. These methods include the original recorder, a forensic image of the original file or storage medium, or a file transfer from the original storage medium. 


Authentication is vital for identifying whether the audio evidence was tampered with. The authentication process often happens when determining the chain of custody, but this isn’t an absolute determiner. During the rest of the analysis process, audio and video forensics experts can decide if a file was edited. 

Using a spectrogram, audio, and video forensic experts identify disruptive or harmful noises in the recording and use advanced software to remove them. 

Forensic audio transcription is the process of converting an audio file into written words. This conversion is completed by a forensic expert under controlled conditions with an enhanced audio recording.

Voice comparison, or speaker recognition, is the analysis of known and unknown voice samples within audio evidence. This procedure is used to confirm or eliminate an individual as the speaker.


At Primeau Forensics, we have 35 years of experience providing audio forensic services, and our team of experts has all the skills necessary to examine media files. With annual technology training and accreditation from law enforcement agencies, you can trust us for audio forensics help. We can provide a thorough, objective analysis for presentation in court. 

We offer pro bono consultations to help you get started. Contact us today to request a proposal for our services.

For more information on our audio forensic services or to discuss how Primeau Forensics can help with your case, contact us today.

Primeau Forensics