Sound Spectrograph
Definition
An instrument that plots the frequency content of a speech signal over time, with frequency on the vertical axis, time on the horizontal, and acoustic energy represented by trace darkness. Developed at Bell Labs in the 1940s; the visual output is a spectrogram.
Related terms
- Daubert Standard
- The US federal evidentiary standard (Daubert v. Merrell Dow Pharmaceuticals, 1993) requiring that expert testimony be based on scientifically valid methods with...
- ENFSI BPM
- The ENFSI Best Practice Manual for Forensic Comparison of Speech (2015, rev. 2022); the operational standard for speaker comparison in European forensic...
- Formant
- A resonance peak in the vocal tract filter; F1 and F2 together characterise vowel quality (height and frontness), while F3 and higher...
- Frye Standard
- The US legal test for admissibility of scientific evidence, originating from Frye v. United States (1923), which required that a technique be...
- IAVI (International Association of Voice Identification)
- Organisation founded by Kersta in the late 1960s to train and certify forensic voice identification examiners in the spectrographic comparison method. Certification...
- Likelihood Ratio (LR)
- The ratio of two conditional probabilities: the probability of the observed evidence given the prosecution's hypothesis (same source), divided by the probability...
- NAS 1979 Report
- The National Academy of Sciences report 'On the Theory and Practice of Voice Identification,' which concluded that spectrographic voice identification lacked the...
- Proficiency Testing
- An external quality assurance programme in which a laboratory analyses blind samples distributed by an independent provider and submits results for comparison...
- Voiceprint
- Lawrence Kersta's 1962 term for the claim that the spectrographic pattern of an individual's speech is unique enough to serve as a...
Explained in
- Spectrographic Voiceprint History and Its Modern RejectionAn instrument that plots the frequency content of a speech signal over time, with frequency on the vertical axis, time on the horizontal, and acoustic energy r...