Pitch Strength Research Articles

Identification of Harmonic Musical Intervals: The Effect of Pitch Register and Tone Duration

Abstract An experiment was conducted to explore the effect of the pitch strength of pure tones constituting a dyad on the accuracy of musical interval identification. Pitch strength was controlled by presenting the intervals in different frequency regions and varying their duration. The intervals were organized into 18 blocks made up by a combination of three octaves: the second (65.4-130.8 Hz), the fourth (261.6- 523.3 Hz), and the sixth octave (1047-2093 Hz), and six tone durations, ranging 50-2000 ms in the second octave, and 10-500 ms in the two higher ones. The results indicate that interval identification improves with increasing pitch strength of the interval’s component tones. The identification scores were much lower in the second octave than in the two higher ones and in all octaves identification worsened as the interval’s duration was shortened. The intervals were most often confused with intervals of similar size rather than with their inversions and intervals of similar sonic character. This finding suggests that the main cue for the identification of harmonic intervals is the pitch distance between two tones. However, in the low pitch range, when the tone pitches are less salient, the impression of consonance may become a helpful, although not very effective cue.

The Perception of Breathiness in the Voices of Pediatric Speakers

The perception of pediatric voice quality has been investigated using clinical protocols developed for adult voices and acoustic analyses designed to identify important physical parameters associated with normal and dysphonic pediatric voices. Laboratory investigations of adult dysphonia have included sophisticated methods, including a psychoacoustic approach that involves a single-variable matching task (SVMT), characterized by high inter- and intra-listener reliability, and analyses that include bio-inspired models of auditory perception that have provided valuable information regarding adult voice quality. To establish the utility of a psychoacoustic approach to the investigation of voice quality perception in the context of pediatric voices? Six listeners judged the breathiness of 20 synthetic vowel stimuli using an SVMT. To support comparisons with previous data, stimuli were modeled after four pediatric speakers and synthesized using Klatt with five parameter settings that influence the perception of breathiness. The population average breathiness judgments were modeled with acoustic measures of loudness ratio, pitch strength, and cepstral peak. Listeners reliably judged the perceived breathiness of pediatric voices, as with previous investigations of breathiness in adult dysphonic voices. Breathiness judgments were accurately modeled by loudness ratio (r2 = 0.93), pitch strength (r2 = 0.91), and cepstral peak (r2 = 0.82). Model accuracy was not affected significantly by including stimulus fundamental frequency and was slightly higher for pediatric than for adult voices. The SVMT proved robust for pediatric voices spanning a wide range of breathiness. The data indicate that this is a promising approach for future investigation of pediatric voice quality.

Do Older Listeners With Hearing Loss Benefit From Dynamic Pitch for Speech Recognition in Noise?

Dynamic pitch, the variation in the fundamental frequency of speech, aids older listeners' speech perception in noise. It is unclear, however, whether some older listeners with hearing loss benefit from strengthened dynamic pitch cues for recognizing speech in certain noise scenarios and how this relative benefit may be associated with individual factors. We first examined older individuals' relative benefit between natural and strong dynamic pitches for better speech recognition in noise. Further, we reported the individual factors of the 2 groups of listeners who benefit differently from natural and strong dynamic pitches. Speech reception thresholds of 13 older listeners with mild-moderate hearing loss were measured using target speech with 3 levels of dynamic pitch strength. Individuals' ability to benefit from dynamic pitch was defined as the speech reception threshold difference between speeches with and without dynamic pitch cues. The relative benefit of natural versus strong dynamic pitch varied across individuals. However, this relative benefit remained consistent for the same individuals across those background noises with temporal modulation. Those listeners who benefited more from strong dynamic pitch reported better subjective speech perception abilities. Strong dynamic pitch may be more beneficial than natural dynamic pitch for some older listeners to recognize speech better in noise, particularly when the noise has temporal modulation.

Development of Phase Locking and Frequency Representation in the Infant Frequency-Following Response.

This study investigates the development of phase locking and frequency representation in infants using the frequency-following response to consonant-vowel syllables. The frequency-following response was recorded in 56 infants and 15 young adults to 2 speech syllables (/ba/ and /ga/), which were presented in randomized order to the right ear. Signal-to-noise ratio and Fsp analyses were used to verify that individual responses were present above the noise floor. Thirty-six and 39 infants met these criteria for the /ba/ or /ga/ syllables, respectively, and 31 infants met the criteria for both syllables. Data were analyzed to obtain measures of phase-locking strength and spectral magnitudes. Phase-locking strength to the fine structure in the consonant-vowel transition was higher in young adults than in infants, but phase locking was equivalent at the fundamental frequency between infants and adults. However, frequency representation of the fundamental frequency was higher in older infants than in either the younger infants or adults. Although spectral amplitudes changed during the first year of life, no changes were found with respect to phase locking to the stimulus envelope. These findings demonstrate the feasibility of obtaining these measures of phase locking and fundamental pitch strength in infants as young as 2 months of age.

Voice production effects due to extreme reverberation times in real rooms

Public school teachers have a heightened risk of voice problems. There are many potential causes of this increased vocal risk, including poor room acoustics (e.g., excessively high or low reverberation times). With increased understanding, rooms could be better designed to maintain communication transfer (intelligibility), while mitigating unhealthy vocal effort and, by extension, voice problems. The present study quantified the influence of a wide range of reverberation times (RT20) on vocal production parameters. Thirty-two participants were recorded completing a battery of speech tasks in eight widely ranging conditions within a reverberation chamber. Changes in RT20 had highly correlated effects on several vocal parameters, including smoothed cepstral peak prominence, acoustic vocal quality index (AVQI), and pitch strength. As RT20 increased, vocal parameters tended toward values commonly associated with dysphonic phonation. Additionally, results were gender dependent, with females tending to produce voice with higher vocal effort than males. These findings begin to objectify the effects of room acoustics on vocal accommodations and provide grounds for developing future talker-oriented room acoustical standards.

Exponential modeling of frequency-following responses in American neonates and adults

Frequency-following response (FFR) has been widely used to assess the mechanisms of speech processing for speakers of tonal and non-tonal languages. For Chinese speaking adults, the characteristics of speech processing with increasing number of sweeps have been described with an exponential curve-fitting model; however, these characteristics for non-tonal language speakers have yet to be described in a similar manner. This study examined the characteristics of speech processing for both adults and neonates who speak a non-tonal language, to determine the goodness-of-fit of an exponential model to neonatal and adult FFRs, and compared the results between groups to determine if any differences exist. Twelve American neonates and 12 American adults were recruited for this study. Participants were native English speakers. The FFR was elicited using the English vowel /i/ with a rising pitch contour for a total of 8000 sweeps from each participant. From the three indices (Frequency Error, Tracking Accuracy and Pitch Strength) computed, the FFR trends were fit to an exponential curve-fitting model to estimate the frequency tracking acuity and neural phase-locking magnitude when the amount of sweeps increased in the averaged waveform. Significant differences between groups were found for the objective indices.

Sound quality evaluation of air-conditioner noise based on factors of the autocorrelation function

The aim of this paper is to clarify the characteristics of air-conditioner noise and determine the factor that is most influential on the subjective annoyance caused by this noise. The A-weighted equivalent continuous sound pressure level (LAeq) and factors extracted from the autocorrelation function (ACF) were analyzed. Subjective annoyance was evaluated using a paired comparison method. Multiple regression analyses were performed using a linear combination of LAeq, the ACF factors, and their standard deviations (SDs). The results indicated that the noise characteristics caused by each air conditioner and each operating level are determined by LAeq, and by the width of the first decay of the ACF, Wϕ(0), which corresponds to the spectral centroid. The multiple regression analyses indicated that the total subjective annoyance caused by air-conditioner noise can be predicted using the delay time and amplitude of the first maximum peak of the ACF (τ1 and ϕ1) and the SD of ϕ1. Annoyance was found to increase with decreasing τ1 and ϕ1, and with increasing ϕ1 SD, suggesting that noise components with higher pitches, weaker pitch strengths, and larger pitch strength variations cause greater levels of annoyance.

Pitch Strength as an Outcome Measure for Treatment of Dysphonia

Measurement of treatment outcomes is critical for the spectrum of voice treatments (ie, surgical, behavioral, or pharmacological). Outcome measures typically include visual (eg, stroboscopic data), auditory (eg, Consensus Auditory-Perceptual Evaluation of Voice; Grade, Roughness, Breathiness, Asthenia, Strain), and objective correlates of vocal fold vibratory characteristics, such as acoustic signals (eg, harmonics-to-noise ratio, cepstral peak prominence) or patient self-reported questionnaires (eg, Voice Handicap Index, Voice-Related Quality of Life). Subjective measures often show high variability, whereas most acoustic measures of voice are only valid for signals where some degree of periodicity can be assumed. However, this assumption is often invalid for dysphonic voices where signal periodicity is suspect. Furthermore, many of these measures are not useful in isolation for diagnostic purposes. We evaluated a recently developed algorithm (Auditory Sawtooth Waveform Inspired Pitch Estimator-Prime [Auditory-SWIPE']) for estimating pitch and pitch strength for dysphonic voices. Whereas fundamental frequency is a physical attribute of a signal, pitch is its psychophysical correlate. As such, the perception of pitch can extend to most signals irrespective of their periodicity. Post hoc analyses were conducted for three groups of patients evaluated and treated for voice problems at a major voice center: (1) muscle tension dysphonia/functional dysphonia, (2) vocal fold mass(es), and (3) presbyphonia. All patients were recorded before and after surgical/behavioral treatment for voice disorders. Pitch and pitch strength for each speaker were computed with the Auditory-SWIPE' algorithm. Comparison of pre- and posttreatment data provides support for pitch strength as a measure of treatment outcomes for dysphonic voices.

Involvement of the Serotonin Transporter Gene in Accurate Subcortical Speech Encoding.

The accurate encoding of speech sounds in the subcortical auditory nervous system is of paramount relevance for human communication, and it has been shown to be altered in different disorders of speech and auditory processing. Importantly, this encoding is plastic and can therefore be enhanced by language and music experience. Whether genetic factors play a role in speech encoding at the subcortical level remains unresolved. Here we show that a common polymorphism in the serotonin transporter gene relates to an accurate and robust neural tracking of speech stimuli in the subcortical auditory pathway. This indicates that serotonin transporter expression, eventually in combination with other polymorphisms, delimits the extent to which lifetime experience shapes the subcortical encoding of speech.

On the influence of sensorineural hearing loss on the pitch strength of bandpass noise

In the perception of environmental noises and in the field of speech and music, tonality plays a crucial role. A tonal character can help the listeners to identify the sound source. However, environmental noises with a tonal character are also considered as especially annoying sounds. The psychoacoustic measure “pitch strength” describes the strength of the tonal sensation evoked by the sound on a scale from weak to strong. For normal-hearing listeners, it was shown in the literature that the pitch strength of bandpass noises decreased with increasing bandwidth when the center frequency was fixed and increased with increasing center frequency when the noise bandwidth was fixed. These results are presumably linked to the frequency selectivity of the auditory system. Since cochlear damage leads to a pathological widening of the auditory filters in the inner ear, an altered perception of pitch strength seems possible. In our study, we investigated whether and to which extent pitch strength is influenced by c...

A Neuronal Network Model for Pitch Selectivity and Representation.

Pitch is a perceptual correlate of periodicity. Sounds with distinct spectra can elicit the same pitch. Despite the importance of pitch perception, understanding the cellular mechanism of pitch perception is still a major challenge and a mechanistic model of pitch is lacking. A multi-stage neuronal network model is developed for pitch frequency estimation using biophysically-based, high-resolution coincidence detector neurons. The neuronal units respond only to highly coincident input among convergent auditory nerve fibers across frequency channels. Their selectivity for only very fast rising slopes of convergent input enables these slope-detectors to distinguish the most prominent coincidences in multi-peaked input time courses. Pitch can then be estimated from the first-order interspike intervals of the slope-detectors. The regular firing pattern of the slope-detector neurons are similar for sounds sharing the same pitch despite the distinct timbres. The decoded pitch strengths also correlate well with the salience of pitch perception as reported by human listeners. Therefore, our model can serve as a neural representation for pitch. Our model performs successfully in estimating the pitch of missing fundamental complexes and reproducing the pitch variation with respect to the frequency shift of inharmonic complexes. It also accounts for the phase sensitivity of pitch perception in the cases of Schroeder phase, alternating phase and random phase relationships. Moreover, our model can also be applied to stochastic sound stimuli, iterated-ripple-noise, and account for their multiple pitch perceptions.

Pitch features of environmental sounds

A number of soundscape studies have suggested the need for suitable parameters for soundscape measurement, in addition to the conventional acoustic parameters. This paper explores the applicability of pitch features that are often used in music analysis and their algorithms to environmental sounds. Based on the existing alternative pitch algorithms for simulating the perception of the auditory system and simplified algorithms for practical applications in the areas of music and speech, the applicable algorithms have been determined, considering common types of sound in everyday soundscapes. Considering a number of pitch parameters, including pitch value, pitch strength, and percentage of audible pitches over time, different pitch characteristics of various environmental sounds have been shown. Among the four sound categories, i.e. water, wind, birdsongs, and urban sounds, generally speaking, both water and wind sounds have low pitch values and pitch strengths; birdsongs have high pitch values and pitch strengths; and urban sounds have low pitch values and a relatively wide range of pitch strengths.

Development of subcortical pitch representation in three-month-old Chinese infants

This study investigated the development of subcortical pitch processing, as reflected by the scalp-recorded frequency-following response, during early infancy. Thirteen Chinese infants who were born and raised in Mandarin-speaking households were recruited to partake in this study. Through a prospective-longitudinal study design, infants were tested twice: at 1–3 days after birth and at three months of age. A set of four contrastive Mandarin pitch contours were used to elicit frequency-following responses. Frequency Error and Pitch Strength were derived to represent the accuracy and magnitude of the elicited responses. Paired-samples t tests were conducted and demonstrated a significant decrease in frequency error and a significant increase in pitch strength at three months of age compared to 1–3 days after birth. Results indicated the developmental trajectory of subcortical pitch processing during the first three months of life.

Assessments of Voice Use and Voice Quality Among College/University Singing Students Ages 18–24 Through Ambulatory Monitoring With a Full Accelerometer Signal

The multiple social and performance demands placed on college/university singers could put their still-developing voices at risk. Previous ambulatory monitoring studies have analyzed the duration, intensity, and frequency (in Hertz) of voice use among such students. Nevertheless, no studies to date have incorporated the simultaneous acoustic voice quality measures into the acquisition of these measures to allow for direct comparison during the same voicing period. Such data could provide greater insight into how young singers use their voices, as well as identify potential correlations between vocal dose and acoustic changes in voice quality. The purpose of this study was to assess the voice use and the estimated voice quality of college/university singing students (18-24 years old, N = 19). Ambulatory monitoring was conducted over three full, consecutive weekdays measuring voice from an unprocessed accelerometer signal measured at the neck. From this signal, traditional vocal dose metrics such as phonation percentage, dose time, cycle dose, and distance dose were analyzed. Additional acoustic measures included perceived pitch, pitch strength, long-term average spectrum slope, alpha ratio, dB sound pressure level 1-3 kHz, and harmonic-to-noise ratio. Major findings from more than 800 hours of recording indicated that among these students (a) higher vocal doses correlated significantly with greater voice intensity, more vocal clarity and less perturbation; and (b) there were significant differences in some acoustic voice quality metrics between nonsinging, solo singing, and choral singing.

Development of Subcortical Pitch Representation in Three-Month-Old Chinese Infants.

This study investigated the development of subcortical pitch processing, as reflected by the scalp-recorded frequency-following response, during early infancy. Thirteen Chinese infants who were born and raised in Mandarin-speaking households were recruited to partake in this study. Through a prospective-longitudinal study design, infants were tested twice: at 1-3 days after birth and at three months of age. A set of four contrastive Mandarin pitch contours were used to elicit frequency-following responses. Frequency Error and Pitch Strength were derived to represent the accuracy and magnitude of the elicited responses. Paired-samples t tests were conducted and demonstrated a significant decrease in Frequency Error and a significant increase in Pitch Strength at three months of age compared to 1-3 days after birth. Results indicated the developmental trajectory of subcortical pitch processing during the first three months of life.

Modeling of Breathy Voice Quality Using Pitch-strength Estimates

The characteristic voice quality of a speaker conveys important linguistic, paralinguistic, and vocal health-related information. Pitch strength refers to the salience of pitch sensation in a sound and was recently reported to be strongly correlated with the magnitude of perceived breathiness based on a small number of voice stimuli. The current study examined the relationship between perceptual judgments of breathiness and computational estimates of pitch strength based on the Aud-SWIPE (P-NP) algorithm for a large number of voice stimuli (330 synthetic and 57 natural). Similar to the earlier study, the current results confirm a strong relationship between estimated pitch strength and listener judgments of breathiness such that low pitch-strength values are associated with voices that have high perceived breathiness. Based on this result, a model was developed for the perception of breathy voice quality using a pitch-strength estimator. Regression functions derived between the pitch-strength estimates and perceptual judgments of breathiness obtained from matching task revealed a linear relationship for a subset of the natural stimuli. We then used this function to obtain predicted breathiness values for the synthetic and the remaining natural stimuli. Predicted breathiness values from our model were highly correlated with the perceptual data for both types of stimuli. Systematic differences between the breathiness of natural and synthetic stimuli are discussed.

Subjective Preference for Air-Conditioner Sounds inside A Car In Summer and Winter

The aim of this paper was to clarify the relationship between subjective preference for air-conditioner sounds and sound quality indices, such as factors extracted from the autocorrelation function (ACF) inside a car in summer and winter. We evaluated subjective preference using a paired comparison method. Specifically, we performed multiple regression analyses with scale values of preference as the outcome variable using a linear combination of LAeq, the ACF factors, and their standard deviations. The results indicated that total subjective preference for air-conditioner sound can be predicted using LAeq, the amplitude of the first maximum peak of the ACF, φ1, which corresponds to the pitch strength, and the width of the first decay of the ACF, Wφ(0), which corresponds to the spectral centroid. We found preference to increase with a decrease in LAeq and φ1, and an increase in Wφ(0). Thus, air-conditioner sounds with quieter levels, weaker pitch strength, and lower spectral centroid were associated with higher levels of preference. The temperature of the atmosphere had no effect on subjective preference for air-conditioner sounds.

Complex pitch perception mechanisms are shared by humans and a New World monkey

The perception of the pitch of harmonic complex sounds is a crucial function of human audition, especially in music and speech processing. Whether the underlying mechanisms of pitch perception are unique to humans, however, is unknown. Based on estimates of frequency resolution at the level of the auditory periphery, psychoacoustic studies in humans have revealed several primary features of central pitch mechanisms. It has been shown that (i) pitch strength of a harmonic tone is dominated by resolved harmonics; (ii) pitch of resolved harmonics is sensitive to the quality of spectral harmonicity; and (iii) pitch of unresolved harmonics is sensitive to the salience of temporal envelope cues. Here we show, for a standard musical tuning fundamental frequency of 440 Hz, that the common marmoset (Callithrix jacchus), a New World monkey with a hearing range similar to that of humans, exhibits all of the primary features of central pitch mechanisms demonstrated in humans. Thus, marmosets and humans may share similar pitch perception mechanisms, suggesting that these mechanisms may have emerged early in primate evolution.

Behavioral and computational estimates of breathiness and roughness over a wide range of dysphonic severity

Perceptual evaluations of dysphonic voices frequently involve evaluation of the breathy and rough qualities. It is important to know how well one can disambiguate such VQ percepts in a perceptual evaluation so that accurate assessments can be made, focused treatment targets can be set, and outcomes can be quantified. In this study, 10 voices that varied over a wide range of breathiness and 10 voices that varied over wide range in roughness were selected from the University of Florida Disordered Voice Database (UFDVD). A single-variable matching task designed specifically for breathiness or roughness evaluation was used to index the perceived breathiness and roughness of the set of 20 stimuli. Because computational estimates of pitch salience (pitch strength) have been strongly associated with perceived breathiness, we also included a perceptual evaluation of pitch strength using an anchored magnitude estimation task. In an effort to better understand the interactions among perceived roughness and breathiness, a series of computational algorithms was used to estimate perceived breathiness and perceived roughness. Together, these results will help us understand the natural covariance of voice qualities and the ability to evaluate separate voice qualities independently.

Acoustic models of co-varying vocal roughness and breathiness

Dysphonia is characterized by several vocal qualities including breathiness and roughness. These qualities can coexist within a single voice. To examine the potential interaction between judgments of one voice quality in the presences of another, a large set of synthetic voices that co-varied along the breathiness and roughness continua were created and evaluated by 10 listeners. The perception of roughness (synthesized via amplitude modulation) was unaffected by degree of breathiness. The perception of breathiness, however, was affected by the degree of roughness: for low-breathy voices breathiness increased by about 2 dB as roughness increased from no roughness to maximum roughness; yet for high-breathy voices, breathiness decreased by about 2 dB as roughness increased. Current acoustic models of voice quality (pitch strength, auto-correlation peak, cepstral peak, partial loudness ratio, and glottal-noise-excitation ratio) do not explain the observed interaction of roughness and breathiness. To explain the observed interaction, we evaluate the possibility that roughness perception is dominated by temporal cues (which are unaffected by the presence of breathiness) and that breathiness perception is driven by spectro-temporal cues which are affected by the sub-harmonics generated by amplitude modulation. The sub-harmonics partially contribute to non-harmonic energy (increasing breathiness) and partially mask aperiodic energy (decreasing breathiness).