Tools for the objective assessment of voice

Praat is a free, open source software package for research and/or clinical practice. This powerful software has been developed by Paul Boersma and David Weenink, Phonetic Sciences, University of Amsterdam.

Although you can record speech directly into Praat, you may wish to edit speech, such as selecting just one utterance or vowel.

This is made relatively easy with Audacity, another free app.

Audacity is available for Mac OS X, Windows and Linux:

I recommend Sound Studio 4 as a paid alternative to Audacity. I prefer the editing, which I find easer. Costs around £49.99 (May 2023).

Guide to free software to evaluate vocal pitch, loudness and screen for voice disorders

The above guide shows Speech and Language Therapists how to use Audacity and Praat to record, edit and analyse voice. The software is all FREE and may be used with a reasonably priced microphone and modern PC, Mac or Linux computer.

The guide walks through:
  • LOUDNESS - Sound Pressure Level (SPL)
  • CPPS - Detecting voice disorder

The Microsoft Word file is for recording a service user's data, which may then be added to their case notes.

If you would like to learn more, please follow the links to tutorials by experts in the field, below.

Praat Plug-ins

State-of-the-art voice/speech clinics through sophisticated and high-quality yet accessible acoustic voice/speech analyses. Commercial web site
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The above PDF shows an analysis of my voice from a reading of The Rainbow Passage (Fairbanks, 1960) using Praat and the Phonanium plug-in. The use of the Rainbow Passage allows a more accurate overall pitch range and median to be calculated.

Fairbanks, G. (1960). Voice and articulation drillbook, 2nd edn. New York: Harper & Row. pp124-139.

A free plug-in with automated scripts for voice processing by Ramon Corretge.

This includes the Change pitch median and variation where voice recordings may be altered to a required pitch.

Download and installation guide.

Identifying Possible Voice Disorder with Cepstral Peak Analysis

Cepstral Analysis is increasingly used clinically "…as an objective measure of breathiness and overall dysphonia." (Murton Hillman & Mehta, 2020).
Saunder, Brett & Eadie concluded that "…these studies support the robust nature of CPPS to detect dysphonia, including disorder status as well as perceived dysphonia, in a variety of different patient populations." (2019, p. 564)

An anagram of 'Spectrum', can be thought of as a spectrum of a spectrum. The cepstral peak prominence (CPP), or smoothed CPP (CPPS) may be calculated using a free plug-in (see below), or a paid-for plug-in by Phonanium (with more detailed statistics and graphical representations of the analysis).

A free plug-in for Praat by Elizabeth Heller Murray (2022). The plug in provides figures relating to a voice sample for CPP (Free).

Voice analysis resources

James Curtis, PhD, CCC-SLP has a very helpful 'walk-through' for Praat functions for Voice Analysis.

Speech, Hearing & Phonetic Sciences, UCL have free, online software, including real-time amplitude and pitch display.
See here for the links to all web-based apps.
Note: Apple Mac users may find that Microsoft Edge web browser will run AMPITCH, but native browsers such as Safari may not work.


Heller Murray, E., Chao, A., & Colletti, L. A. (2022). A Practical Guide to Calculating Cepstral Peak Prominence in Praat. Journal of Voice.

Murton, O., Hillman, R., & Mehta, D. (2020). Cepstral Peak Prominence Values for Clinical Voice Evaluation.
American Journal of Speech-Language Pathology, 29(3), 1596-1607.

Sauder, C., Bretl, M., & Eadie, T. (2017). Predicting Voice Disorder Status From Smoothed Measures of Cepstral Peak Prominence Using Praat and Analysis of Dysphonia in Speech and Voice ( ADSV ).
Journal of Voice, 31(5), 557-566.

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