Acoustic Measures of Voice Quality
A Living Reference
Jorge C. Lucero 
Welcome
Version 0.1 in preparation. This is an early release that grows chapter by chapter. Pages marked Living draft are complete and sourced, and they will be revised as new sources are added.
Acoustic Measures of Voice Quality is an open reference on the acoustic measures used to assess the human voice. It is written for speech-language pathologists and voice scientists. For each measure, it covers what the measure means, how it is computed, which reference values exist, and where the measure fails.
What makes it different
- Every reference value comes with its pipeline. A CPPS cutoff from one program does not apply to a value from another program, and an AVQI threshold validated in one language does not apply to another. Every normative table states the software, version, settings, speech task and language behind each value, and its compatibility class.
- Absence is declared, not filled. Where no published reference matches a pipeline, task or language, the table says so instead of borrowing a number.
- Disagreements are shown, not averaged. When sources conflict, including misprinted equations or inconsistent summary tables, the conflict is set out with both sources.
- Primary sources. Claims are traced to the original studies. Values are never taken from summary tables without saying so.
In this release
Foundations
- Signal Fundamentals: sampling, quantization, framing and windows, and the time, frequency and cepstral domains, with computed figures.
- Signal Typing: the Type 1–4 classification, and which measures are valid for which signals.
- Pipeline Dependence and Reference Values: why a value belongs to the software, settings, task and language that produced it, and how this reference reports reference values.
Measures
Coming next
The complete reference is planned in five parts. The chapters below are not yet written.
- Foundations: recording protocol; F0 detection; voice tasks; perceptual anchors (GRBAS, CAPE-V).
- Periodicity and stability: F0 measures; jitter; shimmer; voice breaks; perturbation caveats.
- Noise and harmonic structure: HNR; NHR; GNE; spectral tilt.
- Composite indices: the Dysphonia Severity Index (DSI); caveats shared by composite indices.
- Machine-learning-derived measures: a landscape chapter and two worked examples.
- Appendices: adjunct methods, reproducibility notes and a glossary.
Citing this reference
Until the v0.1 release receives its DOI, cite the web version with its access date:
Lucero, J. C. (2026). Acoustic Measures of Voice Quality: A Living Reference. https://voicemeasures.org (accessed date).
Each release will be archived on Zenodo with a versioned DOI.