Audio Forensics



Audio waveform of human voice before (top) and after (bottom) forensic audio enhancement.

Audio Forensics:
Includes specialized signal processing for recovering speech or images masked by distortion or background sounds.

Audio Enhancement Techniques:
For audio recordings, a variety of filters can be applied to enhance the material, bringing out specific aspects or events contained in the recording.

Frequency Equalization – Highly precise equalizers can be used to boost or cut specific bands of frequencies. To help make speech more intelligible, the frequency band containing the most speech content, 200Hz-5000Hz, can be amplified or isolated. If amplification is applied to a frequency range, other information residing in this frequency range will be boosted as well. If noise resides in this same range, this noise will also be increased, limiting the ability to clarify voices. Loud background noises may be analyzed by a spectrum analyzer and the corresponding frequencies reduced so that these noises are less noticeable.

Compression – Faint sounds in the recording can be boosted by compression or leveling the signal so that dynamic range of the material is reduced, making soft sounds more apparent.