Level and Center Frequency of the Singer's Formant

Journal of Voice, 2008

The considerable voice timbre differences between musical theater (MT) and western operatic singers are analyzed with respect to voice source and formant frequencies in five representatives of each singer group. Audio, subglottal pressure (P sub ), and electroglottograph (EGG) signals were recorded while the subjects sang a sequence of [pae:] syllables starting at maximal vocal loudness and then gradually decreasing vocal loudness. The task was performed at each of two fundamental frequencies (F 0 ), approximately one octave apart. Ten equally spaced P sub values were then selected for each F 0 . The subsequent vowels were analyzed in terms of flow glottograms derived by inverse filtering the audio signal, which also yielded formant frequency data. Period time (T 0 ), peak-to-peak pulse amplitude (U p-t-p ), and maximum flow declination rate (MFDR) were measured from the flow glottograms while closed quotient Q closed (T cl /T 0 ) was determined in combination with the differentiated EGG signal. Also the relationship between the first and the second harmonic in the spectrum (H 1 -H 2 ), the amplitude quotient (AQ), that is, the ratio between U p-t-p and MFDR, and normalized AQ, that is, AQ normalized with respect to period time was calculated as well as the sound pressure level. The results showed that both the MT and the opera singers varied their P sub systematically, approximately doubling P sub for a doubling of F 0 . For a given value of P sub , the MT singers produced higher values of MFDR, U p-t-p , and Q closed , and lower values of H 1 -H 2 , indicating a weaker fundamental. Further, the MT singers showed higher formant frequencies and did not show the opera singers' characteristic clustering of F 3 , F 4 , and F 5 .

When the soprano raises the fundamental frequency above the first formant of a vowel, a remarkable loss of acoustic energy and linguistic information occurs along with an abrupt change in the voice timbre. To avoid these effects, sopranos are assumed to tune their first formant to the raised fundamental frequency. The support for this claim is mostly based on formant data provided by indirect measurement methods and articulatory data, since direct acoustic data becomes more difficult (or even impossible) to obtain as the fundamental frequency gets higher. In the present study a new combination of measurement methods is introduced. The aim was to extract formant data of three sopranos in the entire set of the Hungarian vowel inventory in a wide pitch range. The results provide evidence for the technique of tuning the first formant to the raised high fundamental frequency in a substantial amount of data.

Journal of Voice, 2013

The term ''formant tuning'' is generally used for the case that one of the lowest formant frequencies coincides with the frequency of a source spectrum partial. Some authors claim that such coincidence is favorable and belongs to the goals of classical opera voice training, whereas other authors have found evidence for advising against it. This investigation analyzes the relationships between formant frequencies and partials in professional singers, who sang scales on the vowels /a/, /u/, /i/, and /ae/ in a pitch range including the passaggio, that is, the fundamental frequency range of approximately 300-400 Hz, applying either of the two singing strategies that are typically used (1) in classical and (2) in nonclassical singing, respectively. Formant frequencies of each note in the scales were measured by inversefiltering the acoustic signal. In the classical style, the first formant tended to be lower than in the nonclassical style. Neither the first nor the second formant tended to change systematically between scale tones, such that on some scale tones either or both formants was just below, just above, or right on a spectrum partial. In many cases, singers produced similar spectrum characteristics of the top tones of the scales with different first and second formant frequencies. Regardless of whether the first formant was slightly lower, slightly higher, or right on a partial, the properties of the voice source did not seem to be affected.

Many years have elapsed since the first articles on various aspects of the singing voice were published. Here my own research on singer's formant, formant tuning, breathing, and voice source are reviewed in the light of later contributions. Detweiler's and Wang's studies of the singer's formant are commented. The idea that singers tend to tune F1 and/or F2 to harmonic partials is analysed and some open questions are pointed out. Various investigations of the voice source and breathing are discussed and some attractive topics for future research are described. The article was written at the request of the recent conference on Physiology and Acoustics of Singing in Groningen, where researchers were asked to review their own research on the singing voice.

Journal of The Acoustical Society of America, 1999

The effects of variations in vocal effort corresponding to common conversation situations on spectral properties of vowels were investigated. A database in which three degrees of vocal effort were suggested to the speakers by varying the distance to their interlocutor in three steps ͑close-0.4 m, normal-1.5 m, and far-6 m͒ was recorded. The speech materials consisted of isolated French vowels, uttered by ten naive speakers in a quiet furnished room. Manual measurements of fundamental frequency F0, frequencies, and amplitudes of the first three formants (F1, F2, F3, A1, A2, and A3͒, and on total amplitude were carried out. The speech materials were perceptually validated in three respects: identity of the vowel, gender of the speaker, and vocal effort. Results indicated that the speech materials were appropriate for the study. Acoustic analysis showed that F0 and F1 were highly correlated with vocal effort and varied at rates close to 5 Hz/dB for F0 and 3.5 Hz/dB for F1. Statistically F2 and F3 did not vary significantly with vocal effort. Formant amplitudes A1, A2, and A3 increased significantly; The amplitudes in the high-frequency range increased more than those in the lower part of the spectrum, revealing a change in spectral tilt. On the average, when the overall amplitude is increased by 10 dB, A1, A2, and A3 are increased by 11, 12.4, and 13 dB, respectively. Using ''auditory'' dimensions, such as the F1 -F0 difference, and a ''spectral center of gravity'' between adjacent formants for representing vowel features did not reveal a better constancy of these parameters with respect to the variations of vocal effort and speaker. Thus a global view is evoked, in which all of the aspects of the signal should be processed simultaneously.

Journal of voice : official journal of the Voice Foundation, 2017

At the upper end of the soprano range, singers adjust their vocal tract to bring one or more of its resonances (Rn) toward a source harmonic, increasing the amplitude of the sound; this process is known as resonance tuning. This study investigated the perception of (R1) and (R2) tuning, key strategies observed in classically trained soprano voices, which were expected to be preferred by listeners. Furthermore, different vowels were compared, whereas previous investigations have usually focused on a single vowel. Listeners compared three synthetic vowel sounds, at four fundamental frequencies (f0), to which four tuning strategies were applied: (A) no tuning, (B) R1 tuned to f0, (C) R2 tuned to 2f0, and (D) both R1 and R2 tuned. Participants compared preference and naturalness for these strategies and were asked to identify each vowel. The preference and naturalness results were similar for /ɑ/, with no clear pattern observed for vowel identification. The results for /u/ showed no cle...

International Journal of Speech-Language Pathology, 2013

The present study examined the possible relationship between classifi cation of professional singing voices and their vocal tract parameters including vocal tract length and volume, and vowel formant frequencies. Acoustic refl ection technology (ART) was used to measure vocal tract length and volume of 107 professional singers: 32 tenors, 25 baritones, 27 sopranos, and 23 mezzo-sopranos. The fi rst three formant frequencies (F1 -F3) of the English vowels /a, ae , i/ produced by the professional singers were also obtained. Results indicated signifi cantly shorter oral and vocal tract length, and smaller oral and vocal tract volume associated with sopranos when compared with mezzo-sopranos. Acoustically, sopranos had higher F1, F2, and F3 values than mezzo-sopranos. The present fi ndings suggest that, in addition to vocal tract length, vocal tract volume may also affect formant frequencies, implying the possibility that classifying professional singing voices is based on both vocal tract length and volume information.

Journal of Voice, 1990

Formant tuning, or using vowel modification to approximate one or both of the two lowest resonances of the vocal tract to harmonics of the glottal source, is a technique advocated by certain pedagogies of singing. In this experiment, two sung phonations of a professional baritone are examined for evidence of the tuning by simultaneous recording of audio, electroglottographic (EGG), and subglottal and supraglottal pressures by means of wideband miniature pressure transducers on a catheter passed through the glottis. The considerable resonance-enhancing effects of formant tuning appear to be intentionally exploited by the singer in response to the demands of the musical phrase. Key Words: Formant--Singing--Subglottal pressure--Supraglottal pressure--Pedagogy of singing--Fundamental frequency--Spectrogram.

Logopedics Phoniatrics Vocology, 2021

Purpose: In overtone singing a singer produces two pitches simultaneously, a low-pitched, continuous drone plus a melody played on the higher, flutelike and strongly enhanced overtones of the drone. The purpose of this study was to analyse underlying acoustical, phonatory and articulatory phenomena. Methods: The voice source was analyzed by inverse filtering the sound, the articulation from a dynamic MRI video of the vocal tract profile, and the lip opening from a frontal-view video recording. Vocal tract cross-distances were measured in the MR recording and converted to area functions, the formant frequencies of which computed. Results: Inverse filtering revealed that the overtone enhancement resulted from a close clustering of formants 2 and 3. The MRI material showed that for low enhanced overtone frequencies (F E) the tongue tip was raised and strongly retracted, while for high F E the tongue tip was less retracted but forming a longer constriction. Thus, the tongue configuration changed from an apical/anterior to a dorsal/posterior articulation. The formant frequencies derived from the area functions matched almost perfectly those used for the inverse filtering. Further, analyses of the area functions revealed that the second formant frequency was strongly dependent on the back cavity, and the third on the front cavity, which acted like a Helmholtz resonator, tuned by the tongue tip position and lip opening. Conclusions: This type of overtone singing can be fully explained by the well-established source-filter theory of voice production, as recently found by Bergevin et al. [1] for another type of overtone singing.

Acoustics, 2022

over a wide pitch range was investigated using a multichannel microphone array with high spatial resolution along the horizontal and vertical axes. A newly created dataset allows to examine voice directivity in classical singing with high resolution in angle and frequency. Three voice production modes (phonation modes) modal, breathy, and pressed that could affect the used mouth opening and voice directivity were investigated. We present detailed results for singing voice directivity and introduce metrics to discuss the differences of complex voice directivity patterns of the whole data in a more compact form. Differences were found between vowels, pitch, and gender (voice types with corresponding vocal range). Differences between the vowels /a:, e:, i:/ and /o:, u:/ and pitch can be addressed by simplified metrics up to about d2/D5/587 Hz, but we found that voice directivity generally depends strongly on pitch. Minor differences were found between voice production modes and found to be more pronounced for female singers. Voice directivity differs at low pitch between vowels with front vowels being most directional. We found that which of the front vowels is most directional depends on the evaluated pitch. This seems to be related to the complex radiation pattern of the human voice, which involves a large inter-subjective variability strongly influenced by the shape of the torso, head, and mouth. All recorded classical sung vowels at high pitches exhibit similar high directionality.