Symphonies of Growth: Unveiling the Impact of Sound Waves on Plant Physiology and Productivity.

The application of sound wave technology to different plant species has revealed that variations in the Hz, sound pressure intensity, treatment duration, and type of setup of the sound source significantly impact the plant performance. A study conducted on cotton plants treated with Plant Acoustic Frequency Technology (PAFT) highlighted improvements across various growth metrics. In particular, the treated samples showed increases in the height, size of the fourth expanded leaf from the final one, count of branches carrying bolls, quantity of bolls, and weight of individual bolls. Another study showed how the impact of a 4 kHz sound stimulus positively promoted plant drought tolerance. In other cases, such as in transgenic rice plants, GUS expression was upregulated at 250 Hz but downregulated at 50 Hz. In the same way, sound frequencies have been found to enhance the osmotic potential, with the highest observed in samples treated with frequencies of 0.5 and 0.8 kHz compared to the control. Furthermore, a sound treatment with a frequency of 0.4 kHz and a sound pressure level (SPL) of 106 dB significantly increased the paddy rice germination index, as evidenced by an increase in the stem height and relative fresh weight. This paper presents a complete, rationalized and updated review of the literature on the effects of sound waves on the physiology and growth parameters of sound-treated plants.

Self-Mixing Interferometer for Acoustic Measurements through Vibrometric Calibration.

The Self-Mixing Interformeter (SMI) is a self-aligned optical interferometer which has been used for acoustic wave sensing in air through the acousto-optic effect. This paper presents how to use a SMI for the measurement of Sound Pressure Level (SPL) in acoustic waveguides. To achieve this, the SMI is first calibrated in situ as a vibrometer. The optical feedback parameters C and α in the strong feedback regime (C≥4.6) are estimated from the SMI vibrometric signals and by the solving of non-linear equations governing the SMI behaviour. The calibration method is validated on synthetic SMI signals simulated from SMI governing equations for C ranging from 5 to 20 and α ranging from 4 to 10. Knowing C and α, the SMI is then used as an acoustic pressure sensor. The SPLs obtained using the SMI are compared with a reference microphone, and a maximal deviation of 2.2 dB is obtained for plane waves of amplitudes ranging from 20 to 860 Pa and frequencies from 614 to 17,900 Hz. The SPL measurements are carried out for C values ranging from 7.1 to 21.5.

Fabrication and Characterization of Diaphragm Headphones Based on Graphene Nanocomposites.

The goal of this paper is to fabricate innovative diaphragm headphones using graphene oxide paper (GOP) and GOP/epoxy nanocomposites (GOPC). Initially, graphene oxide suspension is fabricated, and the vacuum filtration method is adopted to make GOP. Then, vacuum bag molding is used to fabricate GOPC from GOP. Hot pressing and associated molds are adopted to fabricate line-indented (GOPC-L) or curve-indented patterns (GOPC-C) on the GOPC. The performances of one kind of GOP and three kinds of GOPC diaphragm headphones are analyzed based on their sound pressure level (SPL) curves achieved by the Soundcheck measurement system. There are four important processing parameters that will influence the performance of the diaphragm, including material type GOP versus GOPC, indented pattern type, sonication time on suspension, and graphene weight fraction in suspension. Compliances of various diaphragms are measured by the Klippel LPM laser measurement system. The results indicate that effects of sonication time and graphene weight fraction on SPL of GOP and GOPC headphones are in reverse, and this is associated with their difference on compliance (modulus), mass, damping ratio, and microstructure uniformity. Either GOPC-L or GOPC-C seems to improve the microstructure of the GOPC, and leads to better SPL performance. The correlation between the previous four factors and SPLs of four kinds of diaphragm headphones is proposed by using scanning electron microscope (SEM) to examine the microstructure of these diaphragms.

Long-term noise exposures and cardiovascular diseases mortality: A study in 5 U.S. states.

BACKGROUND: Previous studies have linked noise exposure with adverse cardiovascular events. However, evidence remains inconsistent, and most previous studies only focused on traffic noise, excluding other anthropogenic sources like constructions, industrial process and commercial activities. Additionally, few studies have been conducted in the U.S. or evaluated the non-linear exposure-response relationships. METHODS: We conducted a relative incidence analysis study using all cardiovascular diseases mortality as cases (n = 936,019) and external causes mortality (n = 232,491) as contrast outcomes. Mortality records geocoded at residential addresses were obtained from five U.S. states (Indiana, 2007; Kansas, 2007-2009, Missouri, 2010-2019, Ohio, 2007-2013, Texas, 2007-2016). Time-invariant long-term noise exposure was obtained from a validated model developed based on acoustical measurements across 2000-2014. Noises from both natural sources (natural activities, including animals, insects, winds, water flows, thunder, etc.) and anthropogenic sources (human activities, including transportation, industrial activities, community facilities & infrastructures, commercial activities, entertainments, etc.) were included. We used daytime and nighttime total anthropogenic noise & day-night average sound pressure level combining natural and anthropogenic sources as exposures. Logistic regression models were fit controlling for Census tract-level & individual-level characteristics. We examined potential modification by sex by interaction terms and potential non-linear associations by thin plate spline terms. RESULTS: We observed positive associations for daytime anthropogenic L50 (sound level exceeded 50% of time) noise (10-dBA OR = 1.047, 95%CI 1.025-1.069), nighttime anthropogenic L50 noise (10-dBA OR = 1.061, 95%CI 1.033-1.091) in a two-exposure-term model, and overall Ldn (day-night average) sound pressure level (10-dBA OR = 1.064, 95%CI 1.040-1.089) in single-exposure-term model. Females were more susceptible to all three exposures. All exposures showed monotonic positive associations with cardiovascular mortality up to certain thresholds around 45-55 dBA, with a generally flattened or decreasing trend beyond those thresholds. CONCLUSIONS: Both daytime anthropogenic and nighttime anthropogenic noises were associated with cardiovascular disease mortality, and associations were stronger in females.

Vocal Demand Response to the Educational Setting Based Communication Scenarios: A Single Subject Study

Objectives: This was a single-subject study, aimed to demonstrate different vocal demand situations that are typical for primary school and teacher's vocal demand response under two acoustical conditions, with and without voice amplification, during five working days. Methods: The long-term voice dosimetry with Vocal Holter Med (PR.O. Voice Srl) was carried out on a 49-year-old female teacher with voice disorders during daily teaching activities. A sound field amplification system (SFAS) PentaClass Runa was installed in the classroom. Voice dosimetry was provided under two different acoustical conditions: without SFAS (2 days) and with SFAS (3 days). Results: Phonation time percentage, sound pressure level (SPL), SPL SD, fundamental frequency (F0), F0 SD, cycle, and distance doses were investigated in seven communication scenarios (lessons, group/individual classes, sports lessons in the gym and schoolyard, breaks, lunch breaks, and other activities). The median scores of all voice parameters differed significantly between different vocal demand contexts. The significant statistical difference in the vocal demand response was in the communication situations with and without SFAS. In addition, the number of children, reverberation time, and ambient air relative humidity impacted voice SPL and the cycle dose. Conclusions: Lessons, sports lessons held in the gym or schoolyard, breaks, and lunch breaks were considered as high vocal demand communication situations requiring higher voice intensity and fundamental frequency, higher phonation time percentage, cycle, and distance doses. Group/individual work and other teacher activities during the day, unrelated to direct work with students, were categorized as low vocal demand communication scenarios.

Objetivos: Este fue un estudio de sujeto único, cuyo objetivo fue demostrar diferentes situaciones de demanda vocal típicas de la escuela primaria y la respuesta vocal de los docentes bajo dos condiciones acústicas, con y sin amplificación de voz, durante cinco días laborables. Métodos: Se llevó a cabo dosimetría vocal a largo plazo con Vocal Holter Med (PR.O. Voice Srl) durante las actividades diarias de enseñanza en una docente de 49 años con trastornos de la voz. Se instaló un sistema de amplificación de campo sonoro (SFAS) PentaClass Runa en el aula. La dosimetría vocal se realizó bajo dos condiciones acústicas diferentes: sin SFAS (2 días) y con SFAS (3 días). Resultados: Se investigaron el porcentaje de tiempo de fonación, el nivel de presión sonora (SPL), SPL SD, la frecuencia fundamental (F0), F0 SD, ciclos y dosis de distancia en siete escenarios de comunicación diferentes (clases, clases grupales/individuales, clases de educación física en el gimnasio y el patio de la escuela, recreos, almuerzos y otras actividades). Las puntuaciones medias de todos los parámetros vocales diferían significativamente entre los diferentes contextos de demanda vocal. La diferencia estadísticamente significativa en la respuesta a la demanda vocal se observó en las situaciones de comunicación con y sin SFAS. Además, el número de niños, el tiempo de reverberación y la humedad relativa del aire ambiente afectaron al SPL de la voz y la dosis de ciclo. Conclusiones: Las lecciones, las clases de educación física en el gimnasio o el patio de la escuela, los recreos y los almuerzos se consideraron situaciones de comunicación de alta demanda vocal, que requerían una mayor intensidad y frecuencia fundamental de la voz, un mayor porcentaje de tiempo de fonación y dosis de ciclo y distancia más altas. El trabajo grupal/individual y otras actividades del profesor durante el día no relacionadas con el trabajo directo con los estudiantes se categorizaron como escenarios de comunicación de baja demanda vocal.

Cartilage Conduction Sounds in Cases of Wearing Different Transducers on a Head and Torso Simulator with a Manipulated Ear Pinna Simulator.

Cartilage conduction is known widely as a third hearing transmission mechanism after the air and bone conduction methods, and transducers dedicated to the production of cartilage conduction sounds have been developed by several Japanese companies. To estimate the acoustic performance of the five cartilage conduction transducers selected for this study, both airborne sounds and cartilage conduction sounds were measured. Airborne sounds can be measured using a commercial condenser microphone; however, cartilage conduction sounds are impossible to measure using a conventional head and torso simulator (HATS), because the standard-issue ear pinna simulator cannot reproduce cartilage conduction sounds with the same spectral characteristics as the corresponding sounds measured in humans. Therefore, this study replaced the standard-issue simulator with a developed pinna simulator that can produce similar spectral characteristics to those of humans. The HATS manipulated in this manner realized results demonstrating that transducers that fitted the entrance to the external auditory canal more densely could produce greater cartilage conduction sounds. Among the five transducers under test, the ring-shaped device, which was not much larger than the entrance to the canal, satisfied the spectral requirements.

Daily sound exposure of hearing aids users during COVID-19 pandemic in Europe.

Introduction: This study aimed to investigate the daily sound exposure of hearing aid (HA) users during the COVID-19 pandemic, with a specific focus on the impact of different governance intervention levels. Methods: Modern HA technology was employed to measure and compare the sound exposure of HA users in three distinct periods: pre-pandemic, and two 14-day periods during the pandemic, corresponding to varying levels of governance interventions. The study sample comprised a total of 386 HA users in Europe during the pandemic, with daily sound exposure data collected as part of the main dataset. Results: The results revealed that, during the pandemic, the equivalent continuous sound pressure level (SPL) experienced by HA users decreased, while the signal-to-noise ratio (SNR) increased compared to the pre-pandemic period. Notably, this impact was found to be more pronounced (p < 0.05) when individuals were subjected to stronger governance intervention levels, characterized by lower SPL and higher SNR. Discussion: This study highlights the changes in daily sound exposure experienced by HA users during the COVID-19 pandemic, particularly influenced by the extent of governance interventions that restricted social activities. These findings emphasize the importance of considering the effects of pandemic-related governance measures on the sound environments of HA users and have implications for audiological interventions and support strategies during similar crises.

Sex-specific difference in agonistic sounds depends on size of sonic organs in fishes: Testing the hypothesis in the croaking gourami (Labyrinth fishes).

In most vocal fish species, females possess smaller sound-generating organs and vocalize less than males. In certain cases females lack sonic organs, in others differences between sexes are unknown. This study analyzes in detail the relationship between sexual dimorphism of sonic organs and the characteristics of agonistic behavior and of sounds recorded under the same behavioral conditions in a vocal fish species, the croaking gourami Trichopsis vittata. During agonistic contests both sexes stretch and pluck two enhanced (sonic) tendons when beating pectoral fins alternately, resulting in a series of double-pulsed bursts, termed croaking sound. The following anatomical, behavioral, and acoustic variables were analyzed: diameter of enhanced tendons in each specimen, duration of same-sex dyadic contests, number and duration of lateral display bouts and of sounds, number of single- and double-pulsed bursts, burst period, peak-to-peak amplitudes of pulses, dominant frequency and sound pressure level (SPLrms). Female sonic tendons were approximately one-fifth smaller than male's of the same size. Six out of seven behavioral variables did not differ between sexes. Sound characteristics were similar in both sexes except for SPLs, which were on average 5 dB lower in females. The degree of sexual dimorphisms in sonic organs may explain differences in sound characteristics. Sounds differ only in one sound characteristic (SPLrms) in T. vittata, in contrast with the congeneric Trichopsis pumila which possesses a more pronounced sexual dimorphism in sonic organs and in which agonistic sounds differ in all sound properties between sexes.

Data for sound pressure level prediction in lightweight constructions caused by structure-borne sound sources and their uncertainties.

When predicting sound pressure levels induced by structure-borne sound sources and describing the sound propagation path through the building structure as exactly as possible, it is necessary to characterize the vibration behavior of the structure-borne sound sources. In this investigation, the characterization of structure-borne sound sources was performed using the two-stage method (TSM) described in EN 15657. Four different structure-borne sound sources were characterized and subsequently installed in a lightweight test stand. The resulting sound pressure levels in an adjacent receiving room were measured. In the second step, sound pressure levels were predicted according to EN 12354-5 based on the parameters of the structure-borne sound sources. Subsequently, the predicted and the measured sound pressure levels were compared to obtain reliable statements on the achievable accuracy when using source quantities determined by TSM with this prediction method. In addition to the co-submitted article (Vogel et al., 2023), the sound pressure level prediction according to EN 12354-5 in detail is described. Furthermore, all data used are provided.

Innovative instrumentation to strong reduction of the noise levels inside newborn incubators used in the neonatal intensive care units.

In spite of the advent of medical technology, modern newborn incubators (NIs) do not protect them from high noise levels in the neonatal intensive care units (NICUs). Allied to bibliographical research carried out measurements were made inside the dome of a NIs and the results show that the sound pressure levels, or noises, are much more intense than the levels stipulated by the norm NBR IEC 60.601.2.19 of ABNT. These measurements revealed that the NIs air convection system motor is the main source of excess noise. In view of the above, a project was developed with the objective of significantly reducing the noise level inside the dome by modifying the air convection system. Thus, a quantitative study was developed, based on the experimental method, where a ventilation mechanism was designed, constructed and tested, which operated from the network of medical compressed air, present in the NICUs and maternity rooms. Respectively, before and after the modification of the air convection system, the data of relative humidity, air velocity, atmospheric pressure, air temperature and noise [(64.9% ur/33.1% ur); (0.27 m s-1/0.28 m s-1); (1.013.98 hPa/1.013, 60 hPa); (36.5 °C/36.3 °C); (45.9 dBA/30.2 dBA], were collected by electronic meters that registered the conditions of the external and internal environment of the dome of an NI with a passive humidification system. The noise measurements in the environment showed that there was a strong reduction of 15.7 dBA, or 34.2% of internal noise, measured after the modification of the ventilation system, showing a significative performance of the modified NI. Therefore, our results may be a good choose to improve NI acoustics to enable optimal care of the neonate in the neonatal intensive care units.

The effect of sound field amplification systems on vocal demand response in teachers during lessons.

PURPOSE: Sound pressure level (SPL), fundamental frequency (F0), time dose (Dt), cycle dose (Dc), and distance dose (Dd) are components affecting a vocal demand response. The study aimed to investigate the impact of sound field amplification systems (SFAS) on teachers' vocal parameters and determine the user comfort of SFAS use in teachers. METHODS: Twenty female teachers underwent long-term voice dosimetry with Vocal Holter Med (PR.O.Voice Srl) during everyday teaching activities. The SFAS PentaClassRuna (Certes) was installed in classrooms. Voice dosimetry was provided in two different acoustical conditions-without the use of SFAS (one to two days) and with SFAS (one to three days). Teachers underwent voice acoustic and laryngoscopic evaluation before voice dosimetry. Two teachers' groups were formed: teachers with and without vocal nodules. The visual analogue scale measured the user comfort of SFAS. RESULTS: There were no significant differences in vocal parameters and vocal doses between teachers with and without vocal nodules. Voice amplification significantly decreased average F0(-4.4 Hz), Dt%(-3.1%), Dc (-0.4 kcycles), and Dd (-1.3 m) in teachers without vocal nodules and F0 (-8.9 Hz) in teachers with vocal nodules. Vocal doses (Dt%, Dc, Dd) significantly decreased in classrooms with longer reverberation time. The user comfort of the SFAS during the lessons was high in both teachers groups. CONCLUSIONS: SFAS was a mediator between the classroom's environment and the teacher's vocal demand response; it changed teachers' voice production parameters and reduced vocal demand response to satisfy the communication requirements. In addition, voice amplification was more beneficial for teachers without vocal fold lesions.

The correlation between six-minute walking distance and maximum phonation time in healthy adults.

Objectives: This study aimed to determine the association between six-minute walking distance (6MWD) and maximum phonation time (MPT) in healthy adults. Patients and methods: The cross-sectional study was conducted with 50 sedentary nonsingers (32 females, 18 males; mean age: 33.5±8.3 years; range, 18 to 50 years) between February 2021 and April 2021. Subjects with a history of smoking, respiratory symptoms in the last two weeks, and heart, lung, musculoskeletal, and balance problems were excluded. The measurements of MPT and 6MWD were carried out by two different assessors blinded to each other. Results: The mean MPT was higher in male subjects (27.4±7.4 sec vs. 20.6±5.1 sec, p<0.001). In the bivariate analysis, there was a significant correlation between MPT and 6MWD (r=0.621, p<0.001), as well as body height (r=0.421, p=0.002) and the mean fundamental frequency (r=-0.429, p=0.002); however, no association was found with age, body weight, and the mean sound pressure level. After multiple regression, 6MWD was the only factor associated with MPT (p=0.002). Conclusion: There is a significant association between 6MWD and MPT in healthy adults, and the results suggest that aerobic capacity might have a role in improving the ability to sustain phonation.

Acoustic Performance of Stress Gradient-Induced Deflection of Triangular Unimorphic/Bimorphic Cantilevers for MEMS Applications.

This paper reports two piezoelectric materials of lead zirconium titanate (PZT) and aluminum nitride (AlN) used to simulate microelectromechanical system (MEMS) speakers, which inevitably suffered deflections as induced via the stress gradient during the fabrication processes. The main issue is the vibrated deflection from the diaphragm that influences the sound pressure level (SPL) of MEMS speakers. To comprehend the correlation between the geometry of the diaphragm and vibration deflection in cantilevers with the same condition of activated voltage and frequency, we compared four types of geometries of cantilevers including square, hexagon, octagon, and decagon in triangular membranes with unimorphic and bimorphic composition by utilizing finite element method (FEM) for physical and structural analyses. The size of different geometric speakers did not exceed 10.39 mm2; the simulation results reveal that under the same condition of activated voltage, the associated acoustic performance, such as SPL for AlN, is in good comparison with the simulation results of the published literature. These FEM simulation results of different types of cantilever geometries provide a methodology design toward practical applications of piezoelectric MEMS speakers in the acoustic performance of stress gradient-induced deflection in triangular bimorphic membranes.

Urban Traffic Noise Analysis Using UAV-Based Array of Microphones.

(1) Background: Transition to smart cities involves many actions in different fields of activity, such as economy, environment, energy, government, education, living and health, safety and security, and mobility. Environment and mobility are very important in terms of ensuring a good living in urban areas. Considering such arguments, this paper proposes monitoring and mapping of a 3D traffic-generated urban noise emissions using a simple, UAV-based, and low-cost solution. (2) Methods: The collection of relevant sound recordings is performed via a UAV-borne set of microphones, designed in a specific array configuration. Post-measurement data processing is performed to filter unwanted sound and vibrations produced by the UAV rotors. Collected noise information is location- and altitude-labeled to ensure a relevant 3D profile of data. (3) Results: Field measurements of sound levels in different directions and altitudes are presented in the paperwork. (4) Conclusions: The solution of employing UAV for environmental noise mapping results in being minimally invasive, low-cost, and effective in terms of rapidly producing environmental noise pollution maps for reports and future improvements in road infrastructure.

Research on the Sound Insulation Performance of Composite Rubber Reinforced with Hollow Glass Microsphere Based on Acoustic Finite Element Simulation.

The composite rubber reinforced with hollow glass microsphere (HGM) was a promising composite material for noise reduction, and its sound insulation mechanism was studied based on an acoustic finite element simulation to gain the appropriate parameter with certain constraint conditions. The built simulation model included the air domain, polymer domain and inorganic particles domain. The sound insulation mechanism of the composite material was investigated through distributions of the sound pressure and sound pressure level. The influences of the parameters on the sound transmission loss (STL) were researched one by one, such as the densities of the composite rubber and HGM, the acoustic velocities in the polymer and inorganic particle, the frequency of the incident wave, the thickness of the sound insulator, and the diameter, volume ratio and hollow ratio of the HGM. The weighted STL with the 1/3 octave band was treated as the evaluation criterion to compare the sound insulation property with the various parameters. For the limited thicknesses of 1 mm, 2 mm, 3 mm and 4 mm, the corresponding optimal weighted STL of the composite material reached 14.02 dB, 19.88 dB, 22.838 dB and 25.27 dB with the selected parameters, which exhibited an excellent sound insulation performance and could promote the practical applications of the proposed composite rubber reinforced with HGM.

Indoor Positioning Design for Mobile Phones via Integrating a Single Microphone Sensor and an H2 Estimator.

An indoor positioning design developed for mobile phones by integrating a single microphone sensor, an H2 estimator, and tagged sound sources, all with distinct frequencies, is proposed in this investigation. From existing practical experiments, the results summarize a key point for achieving a satisfactory indoor positioning: The estimation accuracy of the instantaneous sound pressure level (SPL) that is inevitably affected by random variations of environmental corruptions dominates the indoor positioning performance. Following this guideline, the proposed H2 estimation design, accompanied by a sound pressure level model, is developed for effectively mitigating the influences of received signal strength (RSS) variations caused by reverberation, reflection, refraction, etc. From the simulation results and practical tests, the proposed design delivers a highly promising indoor positioning performance: an average positioning RMS error of 0.75 m can be obtained, even under the effects of heavy environmental corruptions.

Associations of Personality, Physical and Mental Health with Voice Range Profiles.

OBJECTIVES: There is evidence in the literature that voice characteristics are linked to mental and physical health. The aim of this explorative study was to determine associations between voice parameters measured by a voice range profile (VRP) and personality, mental and physical health. STUDY DESIGN: Cross-sectional population-based study. METHODS: As part of the LIFE-Adult-Study, 2639 individuals aged 18-80 years, randomly sampled from the general population, completed both speaking and singing voice tasks and answered questionnaires on depression, anxiety, life satisfaction, personality and quality of life. The voice parameters used were fundamental frequency, sound pressure level, their ranges and maximum phonation time. The associations were examined with the help of correlation and regression analyses. RESULTS: Wider ranges between the lowest and highest frequency, between the lowest and highest sound pressure level and longer maximum phonation time were significantly correlated with extraversion and quality of life in both sexes, as well as openness and agreeableness in women. Smaller ranges and shorter maximum phonation time were significantly correlated with depression. Neuroticism in men was inversely correlated with the maximum phonation time. In the speaking VRP, the associations for sound pressure level were more pronounced than for the fundamental frequency. The same was true in reverse for the singing VRP. Few associations were found for anxiety, life satisfaction and conscientiousness. CONCLUSIONS: Weak associations between voice parameters derived from the VRP and mental and physical health, as well as personality were seen in this exploratory study. The results indicate that the VRP measurements in a clinical context are not significantly affected by these parameters and thus are a robust measurement method for voice parameters.

Skin Acceleration Levels Estimated by a Neck-surface Accelerometer during Phonation Are Affected by The Mechanical Properties of The Anterior Cervical Skin.

OBJECTIVES: The aim of the present study was to assess whether skin acceleration levels (SAL) estimated by a neck-surface accelerometer (ACC) are affected by the anterior neck skin condition. METHODS: Each of six healthy non-dysphonic participants wore a headset microphone (MIC), had an ACC sensor fitted on the skin over the cervical trachea, and were subsequently asked to gradually increase the vocal loudness during sustained phonation of the vowel /e:/ (crescendo task), while the sound pressure levels on a sound level meter (SPLSLM) and MIC/ACC signals were simultaneously recorded. Root mean squared values were calculated from the MIC and ACC signals as the sound pressure level (SPLMIC) and SAL, respectively, and the relationships between SPLSLM and SAL were compared between neck anteflexion and retroflexion or between outward and inward skin retraction on both sides of the sensor. RESULTS: In the total samples for the successful crescendo performance in a natural head position, the SPLMIC and SPLSLM showed a strong linear correlation (r=0.980), whereas the correlation between the SAL and SPLSLM showed a distorted regression line (r=0.765) with individual differences. In all participants, the anteflexion and inward skin retraction decreased the SAL value at the same SPLSLM value, whereas the retroflexion increased the SAL value at the same SPLSLM value. CONCLUSION: These results demonstrate that the signal intensity of a neck-surface ACC is affected by the condition of the anterior cervical skin, perhaps leading to inter-individual variability in SAL measurements.

Loudness and Pitch of Emotional Stage Speech in Kunqu Opera.

Equivalent sound level (Leq), sound pressure level (SPL) and fundamental frequency (F0) were analyzed in the stage speech of six Kunqu Opera roles, Young woman, Old woman, Young man, Old man, Colorful face and Clown. The roles differ in gender, age, personality and phonation types. Differences among emotions (neutral, sad, angry and happy), singers and roles were examined. For most roles, more similarities were observed between neutral and sad stage speech and between angry and happy stage speeches. In most cases, the latter group showed higher Leq, mean SPL and Mean F0 and larger standard deviation (SD) of SPL difference than the former. Some parameters, such as SD of SPL, the mean of SPL difference and the difference between Leq and mean SPL, also showed the intra-group differences.Young woman role, Young man role and Old woman role were similar in some parameters. Colorful face role and Old man role showed a lot of similarities. Clown role showed the least similarities with the other roles. With regard to gender and age, young roles showed smaller SPL difference, larger correlation coefficient between F0 and SPL and larger mean SPL differences between emotions than old roles; female roles had greater parameter consistency and larger correlation coefficient between F0 and SPL than male roles. The personality and phonation types also effected the characteristics of loudness and pitch. This study showed the importance of speakers' characteristics in emotional speech analysis.

Acoustic-Perceptual Correlates of Voice Among Steam Train Engineers: Effects of Noise and Hearing Protection.

Occupational voice users are at a higher risk for developing voice disorders due to their vocal demands, such as prolonged periods of work-related voice use and nonideal environmental factors, such as speaking above background noise. The current study focused on the effects of background noise and hearing protection on acoustic-perceptual correlates of voice among steam train engineers. Fourteen participants phonated vowel /a/, read a phrase, and described a map under different noise and hearing protection conditions. Relative sound pressure level, relative fundamental frequency, and perceived vocal effort and disturbance decreased in the presence of hearing protection for all noise conditions. In contrast, these acoustic measures increased in the absence of hearing protection supporting Lombard effect. Overall, results of the current study provide insight into possible risks to vocal health in workers exposed to high levels of background noise and use hearing protection.