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Related Concept Videos

Design Example: Vintage Mixing Console01:17

Design Example: Vintage Mixing Console

A sound engineer at a music company recently encountered a problem. The output from their newly acquired studio's vintage mixing console was too low for the requirements of modern recording equipment. To rectify this situation, the engineer decided to design an audio pre-amplifier using an operational amplifier (op-amp) to boost the signal level.
The specifications for the pre-amplifier were clear. It needed to amplify the audio signal by a factor of 10, have an input impedance above 10...
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Detection of Gross Error: The Q Test01:00

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When one or more data points appear far from the rest of the data, there is a need to determine whether they are outliers and whether they should be eliminated from the data set to ensure an accurate representation of the measured value. In many cases, outliers arise from gross errors (or human errors) and do not accurately reflect the underlying phenomenon. In some cases, however, these apparent outliers reflect true phenomenological differences. In these cases, we can use statistical methods...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)01:20

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¹³C NMR: ¹H–¹³C Decoupling01:04

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The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
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Related Experiment Video

Updated: May 30, 2026

Foreign Accent and Forensic Speaker Identification in Voice Lineups: The Influence of Acoustic Features Based on Prosody
09:09

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Published on: September 27, 2024

An inconclusive digital audio authenticity examination: a unique case.

Bruce E Koenig1, Douglas S Lacey

  • 1BEK TEK LLC, 12115 Sangsters Court, Clifton, VA 20124-1947, USA. BEKTEK@cox.net

Journal of Forensic Sciences
|August 23, 2011
PubMed
Summary

Forensic audio authenticity analysis of encrypted recordings failed. The study found that due to the codefendant's involvement in developing the audio format and ease of manipulation, the digital audio files could not be scientifically authenticated.

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Area of Science:

  • Digital Forensics
  • Audio Authenticity Analysis
  • Cryptographic Security

Background:

  • A codefendant in a criminal case provided 35 encrypted digital audio files of recorded conversations.
  • The codefendant possessed expertise in forensic audio authenticity and developed the recording system used.

Purpose of the Study:

  • To conduct an authenticity examination of encrypted digital audio files using a peer-reviewed protocol.
  • To determine if the recordings could be scientifically authenticated given the circumstances.

Main Methods:

  • The study applied nine laboratory steps from an 11-step digital audio authenticity protocol.
  • Analysis focused on the accessibility, conversion, editing, and reconstruction of the encrypted audio files.

Main Results:

  • The encrypted audio files were easily accessed, converted, and edited without detection.
  • The codefendant's direct involvement in developing the proprietary audio format was noted.

Conclusions:

  • The digital audio recordings could not be scientifically authenticated using accepted forensic practices.
  • The ease of undetected manipulation raises significant concerns about the integrity of the evidence.