Electroglottography is a common method for providing noninvasive measurements of glottal activity. The derivative of the electroglottographic signal, however, has not attracted much attention, although it yields reliable indicators of glottal closing instants. The purpose of this paper is to provide a guide to the usefulness of this signal. The main features that are to be found in this signal are presented on the basis of an extensive analysis of a database of items sung by 18 trained singers. Glottal opening and closing instants are related to peaks in the signal; the latter can be used to measure glottal parameters such as fundamental frequency and open quotient. In some cases, peaks are doubled or imprecise, which points to special (but by no means uncommon) glottal configurations. A correlation-based algorithm for the automatic measurement of fundamental frequency and open quotient using the derivative of electroglottographic signals is proposed. It is compared to three other electroglottographic-based methods with regard to the measurement of open quotient in inverse-filtered derived glottal flow. It is shown that agreement with the glottal-flow measurements is much better than most threshold-based measurements in the case of sustained sounds.

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This article presents the results of glottal open-quotient measurements in the case of singing voice production. It explores the relationship between open quotient and laryngeal mechanisms, vocal intensity, and fundamental frequency. The audio and electroglottographic signals of 18 classically trained male and female singers were recorded and analyzed with regard to vocal intensity, fundamental frequency, and open quotient. Fundamental frequency and open quotient are derived from the differentiated electroglottographic signal, using the DECOM (DEgg Correlation-based Open quotient Measurement) method. As male and female phonation may differ in respect to vocal-fold vibratory properties, a distinction is made between two different glottal configurations, which are called laryngeal mechanisms: mechanism 1 (related to chest, modal, and male head register) and mechanism 2 (related to falsetto for male and head register for female). The results show that open quotient depends on the laryngeal mechanisms. It ranges from 0.3 to 0.8 in mechanism 1 and from 0.5 to 0.95 in mechanism 2. The open quotient is strongly related to vocal intensity in mechanism 1 and to fundamental frequency in mechanism 2.

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The pitch perceived for short vocal vibrate tones was measured using a method of adjustment. The stimuli were synthetic vocal tones, produced by a formant synthesizer. The main parameter under study was the tone duration, as a function of the fractional number of vibrate cycles. This parameter was examined in relation to (1) the vibrate extent (0, 50, 100, and 200 cents); (2) the vibrate rate (4, 6, and 8 Hz); (3) the tone nominal frequency (220, 440, 880, and 1500 Hz). Durations ranging from « cycle to 2 cycles were studied. Our results showed that for short tones, the pitch perceived does correspond to a weighted time average of the F0 pattern. A separate perception took place for the high and low parts of the vibrate cycles, for large vibrate extents or slow vibrate rates. This phenomenon was related consistently with the glissande threshold. A simple numerical model of weighted time averaging with threshold was proposed. It demonstrated a good agreement with our experimental data. Finally, the experimental results obtained, and the model proposed, were able to explain the musical perception of complex F0 patterns, like those present in actual singing.

Le phonétogramme par registre (ou mécanisme vibratoire laryngé) résulte de la superposition de deux phonétogrammes élaborés séparément pour chacun des deux principaux registres vocaux. Il permet d’évaluer l’ensemble des possibilités de la voix suivant les deux axes amplitude et fréquence, en rendant compte des possibilités inhérentes à chaque mécanisme. Cette technique permet de mieux comprendre l’influence des zones de passage sur l’aspect général du tracé. Le calcul de l’aire des phonétogrammes par registre laryngé, appliqué à une population de 42 sujets issus de trois catégories: non-chanteurs, chanteurs amateurs et chanteurs confirmés des deux sexes, met en évidence le rôle de la technique vocale sur les potentialités acoustiques du vibrateur laryngé. Enfin, cette approche fournit des informations complémentaires précieuses pour la connaissance des registres vocaux.

Before Garcia, only a few notions of vocal production can be found in earlier singing treatises. In those days the authors wrote mainly upon the art of ornamentation and the rules of good language utterance. In the beginning of the 19th century, a radical change occurred with the development of scientific experiments. Several doctors or physicists drew up theories on human voice production, which were similar to those of sound production in woodwind instruments: flute, reed, or membranous lips. Yet, as the experiments on living human beings were impossible, the true nature of the vocal source remained under discussion. In addition, specific questions arose in regard to singing: Are the different registers produced by different vibrating sources or are they due to modifications of a single vibrating system? What are the reasons for a variation in loudness and in pitch, and how are the variations of voice timbre produced? Facing the contradictory opinions of the most famous scientists, Manuel Garcia Jr showed an astonishing insight as early as 1840, when he wrote his first 'Mémoire sur la voix humaine' presented to the Académie des Sciences de Paris. Being altogether an anatomist, a singer, and a great pedagogue, he could accurately observe the physiological phenomena of human voice in the right way. As the first user of the laryngoscope, he wrote a second paper presented at the Royal Society of London, in 1855, in which he confirmed his previous views. All along the different issues of his well-known singing method, we may see the lucidity and the improvements of Garcia's ideas. The only concession he made to the singers is related to the famous 'Fausset-tête' register, an unfortunate word that was bound to induce confusion later.