What is Forensic Audio Enhancement?

When attorneys are looking for forensic audio enhancement services in New York, they turn to Al Zlogar Forensics Inc. Forensic audio enhancement is the process of improving the listenability and ability to understand the acoustic signals of interest in order to allow the Trier of Fact to hear events that occur in a recording.

Al Zlogar Forensics follows best practices and uses the tools accepted in the scientific community. iZotope RX has filters that still amaze us. For example, De-Reverb removes the excess room tone that interferes with the intelligibility of the words spoken. In addition, we also use Adobe Audition, another program often used for forensic audio enhancement services. We provide forensic audio enhancement services in New York and other cities around the country.

In addition to audio enhancement, Al Zlogar Forensics Inc. also provides forensic audio authentication services.

Critical Listening

Generally, the critical listening process allows Al Zlogar to identify, analyze, and document the time, frequency, and amplitude content to various sources of noise masking the signal of interest.

To clarify, you would say a poor quality audio recording has a low signal-to-noise ratio, the volume of the signal of interest and the volume background noise are almost equal. Al Zlogar’s goal is to enhance audio recordings so that the judge and jury can better understand the events that occur within in the audio recorded evidence.

To explain, the audio enhancement process typically results in a higher signal-to-noise ratio, and aims to improve the intelligibility of the voice signal in a recording.

Listen to before and after forensic audio enhancement recordings taken from actual cases.

forensic noise reduction
Forensic noise reduction
an alternative to compression for forensic audio enhancement
Multiband Compressor

Do you have Unwanted Noise and Interference in your recording?

When conducting forensic analysis of voice recordings, identifying the category of noise helps the investigator use the correct filters to improve the ability to understand words spoken in a recording. There are four classifications of noise:

Tonal Noise

This category of noise occurs from cell phone tones or vibrations, electrical power hum, and acoustic noise from machines oscillating around a specific set of frequencies.

Continuous Broadband Noise

Broadband noise spreads across a broad range of frequencies. Visually, continuous broadband noise will appear as the salt and pepper signatures on a spectrogram. Examples include HVAC units, ventilation systems, machine noise, and tape hiss.

Variable Broadband Noise

Examples of variable broadband noise include wind, rain, background traffic in cities, television, and additional voices in the background. These interferences occupy a broad range of frequencies with varying pitches.

Convolved Noise

Convolved noise is having too much reverb in a recording. Examples include recordings in large rooms, hallways, and any space with reflective acoustic materials.

Suggested Reading: Forensic Analysis of Analog Audio Tape, Three Tips for Forensic Audio Enhancement