Forensic audio is the application of audio technology to the areas of criminal and civil law, security and other matters of public interest.

Phoenix Sound Studios analyse audio recordings for authentication and enhancement in both analogue and digital formats, and forensic transcription. Sophisticated processing techniques are applied to extract meaningful information from contaminated audio and improve the accuracy and reliability for transcription and forensic audio investigation.

Examples could include audio enhancement of voice mail and answering machine recordings, mobile device and concealed audio field recordings providing pre-trial preparation and expert witness testimony.

Phoenix Sound Studios can provide a complete detailed report of all work carried out and if required an audio/visual presentation of the results can be presented to law enforcement agencies, Police, law firms, courts and other investigation agencies.

Sensitive material is kept secure and we provide complete confidentiality. We guarantee it.


Authentication of audio involves four steps-

  1. File analysis. If the audio file is in a digital format, then sometimes the metadata (ID-Tags) or header within the file itself can be examined and information extracted to identify its origins such as date created and software/platform used for its creation.
  2. Listening to the audio to detect any abnormal or abrupt changes in levels and background noise that could indicate possible editing or tampering, anomalies or alterations. Audio is monitored through multiple configurations of speakers in a control room that has had advanced room geometry optimization applied resulting a true flat frequency response. KRK Expose EB8, Event Opal and Yamaha NS-10 monitors are used.
  3. Software is used for measurement of certain frequencies and levels in program material. Spectrum analysis and spectral repair are utilized to detect specific characteristics and repair digital audio.
  4. Visual examination of audio files is used to identify any abnormal or abrupt changes in levels and background noise that could indicate possible editing or tampering of audio, anomalies or alterations.

 Below is example of an edit point or alteration that was difficult to hear when critically listening however became quite obvious under visual examination. As you can see the noise floor has been cut and has disappeared momentarily indicating that the recording was not continuous and had been altered whether intentionally or unintentionally.


Certain filters can be applied to enhance and bring more clarity to audio recordings.

Compression and normalizing of audio are used to bring quiet sections up in volume and control the dynamic range or the material.

Equalization is used to cut or boost certain frequencies. This can either drastically reduce unwanted noise or make speech more intelligible.

Proprietary filters and spectral repair are used to remove elements of a recording such as spikes, hum, pops and unwanted noise.

Forensic Transcription

This process usually occurs after the enhancement of audio. Once audio is intelligible a direct transcription of the words or conversation spoken is documented.