Phonogram

Abstract

The Fonetogram, also known academically as the Voice Range Profile (VRP) or Phonetogram, is a critical instrumental assessment tool used in voice analysis and speech pathology. It graphically maps the maximum dynamic range of the human voice, encompassing both the speaking and singing modalities. This measurement captures the vocal capacity across two primary dimensions: pitch (frequency) and volume (intensity). The resulting graph provides a visual representation of the subject’s vocal function, often employed to diagnose and monitor voice disorders. Data acquisition can be performed manually using traditional instruments or automatically via specialized computer software, with automatic methods offering the added benefit of measuring detailed voice quality characteristics.

Keywords

Fonetogram, Phonetography, Voice Range Profile, Vocal Assessment, Frequency, Intensity, Jitter, Shimmer, Voice Disorder, Speech Pathology, Calvet P, Malhiac G.

Authors

Calvet P, Malhiac G (1952), Waar C, Damsté P (1968) (Dutch version).

Purpose

The primary purpose of phonetography is to objectively quantify the physiological limits and dynamic capabilities of the patient’s voice production system. By charting the minimum and maximum vocal intensity levels achievable across the subject’s fundamental frequency range, clinicians can derive critical parameters related to vocal health, efficiency, and potential pathology. This diagnostic instrument is fundamental for establishing a baseline for treatment planning, especially in cases involving vocal fatigue or suspected laryngeal dysfunction.

Furthermore, the Fonetogram serves as an important tool for tracking the progress of patients undergoing voice therapy. Changes in the size or shape of the vocal area plotted on the graph can indicate improvements or deterioration in vocal function. When conducted automatically, the system can also provide detailed metrics on voice quality characteristics, such as measures of periodicity including jitter and shimmer, and the speed of vocal fold closure (crest factor).

Construct

The Fonetogram measures the physiological construct of Vocal Dynamic Range and Maximum Phonation Range. This construct reflects the physical capacity of the laryngeal system and respiratory support mechanism to produce sound across varying degrees of frequency (Hz) and sound pressure level (dB). A healthy, robust vocal system is typically characterized by a large, symmetrical phonetogram area, indicating optimal coordination and efficiency.

The assessment implicitly measures the coordination between the respiratory system (the power source), the laryngeal system (the vibratory source), and the vocal tract (the resonator). The procedure requires the subject to demonstrate precise motor control and auditory feedback processing, especially during the challenging tasks of sustaining minimal intensity at high and low frequencies, which are often the first ranges affected by vocal pathology.

Validity

While the original source material does not explicitly detail specific validity studies, the concept of the Fonetogram possesses high face and ecological validity in speech pathology. It directly measures the physical limits of voice production, which correlates strongly with perceived vocal effort and functional capacity. Clinical validity is generally established through its widespread use in diagnosing conditions like vocal fold paralysis, nodules, and muscle tension dysphonia across various international clinical guidelines.

Validation studies often focus on comparing the area or shape of the phonetogram against standardized acoustic measures and subjective perceptual evaluations (e.g., GRBAS scale) to confirm its diagnostic accuracy as a representation of overall vocal health. The physical contour provides quantifiable data that can be correlated with objective physiological status.

Reliability

The reliability of the Fonetogram depends significantly on the administration method and the subject’s ability to consistently follow instructions. Automatic systems generally yield higher test-retest reliability due to precise acoustic capture and automated plotting, minimizing researcher variability and error associated with manual measurement.

In manual administration, inter-rater reliability can be challenged by the researcher’s judgment regarding whether the subject correctly matches the target pitch and the accuracy of manual sound pressure level readings. Achieving high internal consistency relies on strictly standardized testing procedures, including consistent microphone placement, precise calibration of the testing environment, and clear operational definitions for maximum and minimum voice production.

Factor Analysis

As the Fonetogram is fundamentally an instrumental measurement plotting two continuous physical variables (frequency and intensity) rather than a psychometric scale composed of discrete items, traditional factor analysis is not typically applied to the scale itself. The result is a contour map representing physical vocal performance.

However, analysis of the resulting graph features—such as the total area, the maximum range, the minimum intensity curve, and the symmetry of the boundaries—can be subjected to statistical analysis to identify primary components of vocal dysfunction (e.g., factors related to breath support versus factors related to laryngeal control or mucosal wave disturbances).

Instrument

Test Type: Instrumental Assessment / Physiological Measurement

Format: Graphical representation of vocal range (Voice Range Profile)

Language Available: Standardized procedures allow for use across all languages, though the Dutch version was established by Waar C and Damsté P in 1968.

Population Group: Clinical and research populations focusing on voice and speech functions.

Age Group: Adults (Volwassenen)

Population Details: Individuals presenting with suspected voice disorders, professional voice users (singers, actors), or those undergoing treatment for head/neck conditions. The instrument is highly relevant for assessing the impact of systemic diseases or surgical procedures on laryngeal function.

Test Methodology: The client is instructed to match presented tones across a range of frequencies, first producing the sound as softly as possible, and then as loudly as possible. This is performed in a standardized, quiet sound environment. Methods include:

• Manual Registration: Utilizes a tone generator (e.g., piano) and a calibrated sound pressure meter. Data is plotted manually by the examiner, relying on the subject’s auditory feedback and the examiner’s judgment regarding pitch accuracy.
• Automatic Registration: Computerized systems measure pitch and sound level instantaneously, providing direct visual feedback to the subject via a video screen and allowing for the simultaneous, objective measurement of acoustic parameters like jitter and shimmer.

Keywords

Vocal function assessment, Phonation, Speech pathology, Maximum Phonation Time, Laryngeal function, Sound pressure level, Voice therapy, Acoustic analysis, Crest factor.

Authors

Author ORCID Identifier: Information not provided in source material.

Affiliation Email addresses: Information not provided in source material.

Correspondence Address: Information not provided in source material.

Permissions & Fee and Test Year

The original concept of the Fonetogram was introduced by Calvet P and Malhiac G in 1952. The Dutch adaptation was published in 1968. As the Fonetogram is a standardized instrumental measurement technique rather than a single proprietary test, permissions generally relate to the specific commercial software or equipment used for automatic data acquisition.

The original PDF explanation form for the Dutch version can be downloaded here: Toelichtingsformulier (Explanation Form).

Reference’s

Calvet P, Malhiac G. (1952). Original research introducing the concept of the voice range profile.

Waar C, Damsté P. (1968). Dutch adaptation and standardization of the Fonetogram methodology.

Coleman, R. F. (1993). Phonetography: A clinical tool. In R. F. Coleman (Ed.), Clinical Voice Pathology: An Interdisciplinary Approach (3rd ed.).

Items of the Fonetogram

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

Met fonetografie wordt het maximale, dynamische bereik van de spreekstem en/of zangstem, zowel in toonhoogte (frequentie) als in omvang (intensiteit), in kaart gebracht. Dit wordt vastgelegd in een grafiek, het fonetogram. Een individueel fonetogram wordt verkregen door in een onderzoekskamer de cliënt aangeboden tonen van een aantal frequenties zo zacht mogelijk en vervolgens zo luid mogelijk te laten nazingen. Dit kan handmatig of automatisch afgenomen worden. Bij handmatige afname worden een toongever (b.v. piano) en een geluidsdrukmeter als meetinstrumenten gebruikt. De onderzoeker vult handmatig deze gegevens in een grafiek in. De proefpersonen moeten de tonen juist kunnen overnemen en de onderzoeker moet oordelen of dit juist gebeurt. Bij een automatische registratie worden toonhoogte en geluidsniveau door de computer bepaald en direct in een fonetogram op het beeldscherm weergegeven. De proefpersoon krijgt visuele feedback door een videoscherm. Bij automatische fonetografie is het ook mogelijk stemkwaliteitskenmerken te meten, zoals periodiciteit (jitter, shimmer) en snelheid van stembandsluiting (crest- factor).