Relative Sound Level Research Articles

Do Acoustic Characteristics of Dysarthria in People With Parkinson's Disease Differ Across Languages?

Cross-language studies suggest more similarities than differences in how dysarthria affects the speech of people with Parkinson's disease (PwPD) who speak different languages. In this study, we aimed to identify the relative contribution of acoustic variables to distinguish PwPD from controls who spoke varieties of two Romance languages, French and Portuguese. This bi-national, cross-sectional, and case-controlled study included 129 PwPD and 124 healthy controls who spoke French or Portuguese. All participants underwent the same clinical examinations, voice/speech recordings, and self-assessment questionnaires. PwPD were evaluated off and on optimal medication. Inferential analyses included Disease (controls vs. PwPD) and Language (French vs. Portuguese) as factors, and random decision forest algorithms identified relevant acoustic variables able to distinguish participants: (a) by language (French vs. Portuguese) and (b) by clinical status (PwPD on and off medication vs. controls). French-speaking and Portuguese-speaking individuals were distinguished from each other with over 90% accuracy by five acoustic variables (the mean fundamental frequency and the shimmer of the sustained vowel /a/ production, the oral diadochokinesis performance index, the relative sound level pressure and the relative sound pressure level standard deviation of the text reading). A distinct set of parameters discriminated between controls and PwPD: for men, maximum phonation time and the oral diadochokinesis speech proportion were the most significant variables; for women, variables calculated from the oral diadochokinesis were the most discriminative. Acoustic variables related to phonation and voice quality distinguished between speakers of the two languages. Variables related to pneumophonic coordination and articulation rate were the more effective in distinguishing PwPD from controls. Thus, our research findings support that respiration and diadochokinesis tasks appear to be the most appropriate to pinpoint signs of dysarthria, which are largely homogeneous and language-universal. In contrast, identifying language-specific variables with the speech tasks and acoustic variables studied was less conclusive.

Correction to: Distance estimation of howling golden jackals (Canis aureus) using relative sound level

Correction to: Distance estimation of howling golden jackals (Canis aureus) using relative sound level

Distance estimation of howling golden jackals (Canis aureus) using relative sound level

Golden jackals (Canis aureus) display a complex repertoire of calls, utilized in different communication types (e.g., marking territories, attraction of mating partners). Resident golden jackal groups can successfully be detected by active bioacoustic stimulation, as well as with passive recording devices. For monitoring, basic knowledge of the calls of the focal species and potential restrictions and strengths of the monitoring devices should be considered. We therefore tested possible applications of a low-budget autonomous recording unit for bioacoustic golden jackal monitoring and examined the following research questions: How far can group calls be detected? Can the distance to the recording device be estimated? To answer these questions, we placed 11 AudioMoth recording devices in a linear transect to record live imitated and replayed howls. For the estimation of the number of responding animals, the number of howling individuals was determined based on the maximum number of simultaneously visible fundamental frequencies in a spectrogram. To predict the distance of the playback howls to the recording devices, the relative sound level (RSL) of each call was measured and fitted in linear models. Reliable distance estimations using RSL were possible up to 400 m. Estimated number of responding animals showed a negative relationship with distance. Our results present a baseline for future studies and show that AudioMoths can be a helpful asset in distance estimation of golden jackal packs—both in passive but also active monitoring.

Estimating bird density using passive acoustic monitoring: a review of methods and suggestions for further research

Passive acoustic monitoring is a non‐invasive tool for automated wildlife monitoring. This technique has several advantages and addresses many of the biases related to traditional field surveys. However, locating animal sounds using autonomous recording units (ARUs) can be technically challenging and therefore ARUs have traditionally been little employed to estimate animal density. Nonetheless, several approaches have been proposed in recent years to carry out acoustic‐based bird density estimations. We conducted a literature review of studies that used ARUs for estimating bird densities or bird abundances in order to describe the applications and improve future monitoring programmes. We detected a growing interest in the use of ARUs for estimating bird density in the last 6 years (2014–19), with a total of 31 articles assessing the topic. The most common approach was to estimate the relationship between the number of vocalizations per recording time with bird density or bird abundance estimated in the field (61%). In 26 studies (79%), bird estimates obtained by human surveyors agreed with those obtained using ARUs. Some approaches have proven able to reduce biases in acoustic surveys, such as considering imperfect detection (spatially explicit capture–recapture, using microphone arrays), applying paired acoustic sampling to control for different sampling radius between humans and ARUs, or including relative sound level measurements that allow researchers to estimate bird distance to recorder. However, several studies did not include any covariates to reduce existing biases and some did not estimate the sampling radius of the recorder, which may hamper future comparisons between human and ARU surveys. Future studies should include a measurement of the sampling radius of the recorder employed to be able to obtain density estimations using ARUs. Finally, we provide some guidelines to improve the applicability of ARUs to infer bird population estimates in future studies.

Sound level measurements from audio recordings provide objective distance estimates for distance sampling wildlife populations

AbstractDistance sampling is widely used to estimate animal population densities by accounting for imperfect detection of individuals with increasing distance from an observer. Distance sampling assumes that distances are measured without error; however, it is often applied to human estimated distances, which are known to be inconsistent, inaccurate, and biased. We present an objective technique for estimating distance to vocalizing individuals that relies on the relative sound level (RSL) of the vocalization extracted from autonomous recording unit (ARU) recordings and show the error is less than human estimated error extracted from a literature case study.RSLpredicted distances can be obtained by manual measurement in sound viewing software, or automatically with automated signal recognition software. We built calibration datasets of Ovenbirds (Seiurus aurocapilla) and Common Nighthawks (Chordeiles minor) recorded at known distances and used regression ofRSLfrom those recordings to predict distance. There was no error bias ofRSLpredicted distances when compared to known distances for Common Nighthawk, minimal error bias for Ovenbird, and error from allRSLpredicted distances was less than human estimated error extracted from the literature. We then simulatedARUpoint count surveys with a known density and estimated that density with distance sampling to test whetherRSLdistance prediction does not violate the assumption that distances are measured without error. There was no difference in density estimates from known distance and density estimates obtained fromRSLpredicted distance, while density estimates contaminated with human estimated error were significantly lower than density estimates from known distance. We found that a calibration dataset of approximately 300 vocalizations was suitable to minimize error for both species, and so conclude thatRSLdistance prediction is an accessible method of improving distance estimates relative to human estimation. We provide general recommendations on how to collect calibration recordings for the application ofRSLdistance prediction to other species and areas.

Modelling sound propagation from a wind turbine under various atmospheric conditions

Sound propagation from a wind turbine is investigated with the help of coupled atmospheric and acoustical simulation. Eight instants of time during nine diurnal cycles of idealized large-scale cases result in 72 meteorological situations for which the boundary-layer profiles of wind and temperature, the downstream wake flow of the rotor, and the sound propagation from the wind turbine into upwind and downwind direction were calculated. The resulting sound levels are evaluated relative to a non-refractive atmosphere to focus on the impact of meteorologically induced refraction. Within a range of 1 km from the turbine the sound levels vary stronger in upwind direction than in downwind direction, and the varying background wind speed at hub level causes a higher variability of the relative sound levels than the variations of the surface-layer stability. Surface-layer parameters turn out to be of only limited suitability for a meteorological classification of the wind-turbine noise impact.

QUIETE: a scheme for a new index of the environmental quality of green areas

Abstract Notwithstanding the green areas are important for preserving and promoting the health of population, they are often exposed to noise pollution, especially in urban areas. However, the perceived quality of a green area does not depend only by its sonic environment, as all the human senses contribute to form the individual appraisal together with other features of the area. Thus, an holistic approach is required as that offered by the soundscape approach. The present paper proposes the scheme of a new index, QUIETE, to quantify the quality of a public park, taking into account its perceived overall quality and the relative sound level determined by the difference between the noise descriptor LA (i.e. LAeq, LA50, . . .) and a reference level Lref . By the QUIETE index it is easy to identify the areas requiring noise mitigation actions, and provide understandable information to the users of the park on the areas for their enjoyable fruition. The formulation of the QUIETE index is rather flexible and the reference level Lref has to be fixed considering the objective to accomplish. To evaluate the feasibility and potential of QUIETE, it has been applied to the data collected in 8 urban parks in Milan and Rome with different location (from downtown to suburban area) and size. The Lref value has been set at the noise limit issued by current Italian legislation for green areas (LAeq = 50 dBA for day-time). A “tentative” rating scale for QUIETE is also proposed and its values are reported by a colored scale on the map of the park to summarize the data and to pr

Long-term, global-scale statistics of sound propagation.

The near-surface sound levels emitted due to a point source show a large variability caused by sound propagation through changing meteorological conditions. To assess this variability, this study uses a numerical model of sound propagation which accounts for ground reflection, atmospheric refraction, and turbulence effects. The atmospheric inputs to the model-including turbulence-are calculated from Numerical Weather Prediction data. The method is used to investigate the relative sound levels at a range of 1.5 km from a 40 Hz sound source. The outstanding diversity of sound propagation conditions is illustrated over the globe. Over the long term, the sound propagation climates at selected sites are found to be modulated by the dominant wind regimes, the seasonal and diurnal cycles. The explored sensitivities stress the need for a careful assessment of sound scattering by turbulence and absorption by the surface.

Sound-Strength Driven Parametric Design of an Acoustic Shell in a Free Field Environment

Focusing on the issues of sound propagation in a free field condition and on the concept of uniform sound energy in an outdoor performance environment, our research aimed to develop a computer-aided process for the generation of reflective acoustic surfaces to be used as concert-shells, a computational design tool for acoustic form-finding. The project is ultimately aimed to investigate the acoustic potential of complex and doubly-curved surfaces through the analysis of the Total Relative Sound Level / Strength parameter (G), with reference to the proposed values set by M. Barron, based upon the source-receiver distance and the subsequent subjective judgments on loudness. A simplified and fast ray-tracing acoustic simulation algorithm was developed in combination with parametrically controlled shape variations of the reflective surfaces. Sound energy uniformity evaluation function considering the direct and reflected sound components was written in order to define and evaluate the rate of distribution uniformity of sonic energy over an audience. This evaluation function was used in a genetic algorithm that enabled us to explore a wide set of surface morphologies which allowed us to isolate the fittest one to our specific uniformity requirements. At the end of the genetic search, an acoustic simulation plug-in called Pachyderm was employed with both NURBS and mesh-based acoustic simulations in order to validate the genetically selected surfaces with specific reference to G values. A further step of resultant data visualization and human selection was necessary to compare the output data and to evaluate the final surfaces from an architectural perspective.

A New Context‐Based Approach to Assess Marine Mammal Behavioral Responses to Anthropogenic Sounds

Acute effects of anthropogenic sounds on marine mammals, such as from military sonars, energy development, and offshore construction, have received considerable international attention from scientists, regulators, and industry. Moreover, there has been increasing recognition and concern about the potential chronic effects of human activities (e.g., shipping). It has been demonstrated that increases in human activity and background noise can alter habitats of marine animals and potentially mask communications for species that rely on sound to mate, feed, avoid predators, and navigate. Without exception, regulatory agencies required to assess and manage the effects of noise on marine mammals have addressed only the acute effects of noise on hearing and behavior. Furthermore, they have relied on a single exposure metric to assess acute effects: the absolute sound level received by the animal. There is compelling evidence that factors other than received sound level, including the activity state of animals exposed to different sounds, the nature and novelty of a sound, and spatial relations between sound source and receiving animals (i.e., the exposure context) strongly affect the probability of a behavioral response. A more comprehensive assessment method is needed that accounts for the fact that multiple contextual factors can affect how animals respond to both acute and chronic noise. We propose a three-part approach. The first includes measurement and evaluation of context-based behavioral responses of marine mammals exposed to various sounds. The second includes new assessment metrics that emphasize relative sound levels (i.e., ratio of signal to background noise and level above hearing threshold). The third considers the effects of chronic and acute noise exposure. All three aspects of sound exposure (context, relative sound level, and chronic noise) mediate behavioral response, and we suggest they be integrated into ecosystem-level management and the spatial planning of human offshore activities.

An Exploratory Study of Voice Change Associated With Healthy Speakers After Transcutaneous Electrical Stimulation to Laryngeal Muscles

The purpose of this study was to determine if measurable changes in fundamental frequency (F(0)) and relative sound level (RSL) occurred in healthy speakers after transcutaneous electrical stimulation (TES) as applied via VitalStim (Chattanooga Group, Chattanooga, TN). A prospective, repeated-measures design. Ten healthy female and 10 healthy male speakers, 20-53 years of age, participated in the study. All participants were nonsmokers and reported negative history for voice disorders. Participants received 1 hour of TES while engaged in eating, drinking, and conversation to simulate a typical dysphagia therapy protocol. Voice recordings were obtained before and immediately after TES. The voice samples consisted of a sustained vowel task and reading of the Rainbow Passage. Measurements of F(0) and RSL were obtained using TF32 (Milenkovic, 2005, University of Wisconsin). The participants also reported any sensations 5 minutes and 24 hours after TES. Measurable changes in F(0) and RSL were found for both tasks but were variable in direction and magnitude. These changes were not statistically significant. Subjective comments ranged from reports of a vocal warm-up feeling to delayed onset muscle soreness. These findings demonstrate that application of TES produces measurable changes in F(0) and RSL. However, the direction and magnitude of these changes are highly variable. Further research is needed to determine factors that may affect the extent to which TES contributes to significant changes in voice.

Pinna Cues Determine Orienting Response Modes to Synchronous Sounds in Elevation

To program a goal-directed orienting response toward a sound source embedded in an acoustic scene, the audiomotor system should detect and select the target against a background. Here, we focus on whether the system can segregate synchronous sounds in the midsagittal plane (elevation), a task requiring the auditory system to dissociate the pinna-induced spectral localization cues. Human listeners made rapid head-orienting responses toward either a single sound source (broadband buzzer or Gaussian noise) or toward two simultaneously presented sounds (buzzer and noise) at a wide variety of locations in the midsagittal plane. In the latter case, listeners had to orient to the buzzer (target) and ignore the noise (nontarget). In the single-sound condition, localization was accurate. However, in the double-sound condition, response endpoints depended on relative sound level and spatial disparity. The loudest sound dominated the responses, regardless of whether it was the target or the nontarget. When the sounds had about equal intensities and their spatial disparity was sufficiently small, endpoint distributions were well described by weighted averaging. However, when spatial disparities exceeded approximately 45 degrees, response endpoint distributions became bimodal. Similar response behavior has been reported for visuomotor experiments, for which averaging and bimodal endpoint distributions are thought to arise from neural interactions within retinotopically organized visuomotor maps. We show, however, that the auditory-evoked responses can be well explained by the idiosyncratic acoustics of the pinnae. Hence basic principles of target representation and selection for audition and vision appear to differ profoundly.

Laryngeal aerodynamics associated with oral contraceptive use: Preliminary findings

The purpose of this study was to examine possible differences in laryngeal aerodynamic measures during connected speech associated with oral contraceptive (OC) use. Eight women taking an OC, and eight others not taking an OC, participated in the study. Three trials of syllable /p ▪/repetitions were obtained using a circumferentially vented face mask and small translabial tube. All participants were recorded on or near days 7 and 14 of their menstrual cycle. Subglottal pressure ( P SG) and average airflow rates were obtained to determine laryngeal airway resistance. Glottal airflow measures of peak flow, minimum flow, alternating flow, as well as relative sound level (RSL) were obtained. P SG was obtained from the pressure peak associated with/p/. All airflow parameters and RSL were obtained from the vowel portion. No significant differences were found related to day of recording or OC use, indicating that OC use does not significantly affect laryngeal airflow regulation. Learning outcomes The reader will better understand the effects of hormones and oral contraceptives on the female voice, as well as the specific changes in vocal function that may occur in conjunction with the use of oral contraceptives.

Quantification of Airframe Noise Using Microphone Arrays in Open and Closed wind Tunnels

The reliability of the phased array technique for quantifying airframe noise was assessed in the DNW-LLF open and closed wind tunnel sections. Acoustic measurements were performed on wing noise from a 1:10.6 scaled Airbus A340 model, using a 4-m diameter out-of-flow microphone array in the open jet and a 1-m diameter wall array in the closed test section. Apart from the differences in array resolution, the source characteristics are generally similar for both test sections. The open jet results show that, although the absolute integrated array level can be too low due to e.g. coherence loss, the relative sound levels determined with the array (i.e. differences between configurations) are accurate within 0.5 dB. The difference between the absolute array levels in the closed test section and the farfield levels in the open jet is smaller than 3 dB for all frequencies. The relative array levels in the closed test section agree with the open jet within 1 dB, provided that the flow conditions - and therefore the noise source characteristics -are similar.

Influence of vehicle noise emission directivity on sound level distribution in a canyon street. Part II: Experimental verification

In the paper, predictions of relative sound level distribution on building façades in city-centres obtained by using the simulation PROP11 program are compared with measurements. The simulation involves the geometry of surrounding buildings, road geometry (number of lanes and their positions) and traffic structure (vehicle flow rates and their average speeds). The agreement between measurement and simulation results is tested for different directivity characteristics of an equivalent point source representing the vehicles.

Perceived spatial impression from various musical motifs

Most of the objective measures which are currently used to quantify spatial impression in auditoria, such as lateral energy fraction (LF), interaural cross-correlation coefficient (IACC) and late lateral relative sound level (GLL), are calculated from an impulse response. For subjective testing, these impulse responses are often later convolved with music recorded in an anechoic environment to simulate music performance in the hall. One spatial impression measure, though, interaural level fluctuations (IALFs) which was first proposed by Griesinger [Aud. Eng. Soc., Preprint No. 3292 (1992)] and further developed by L. M. Wang and A. C. Gade [J. Acoust. Soc. Am. 107, 2891(A) (2000)], is calculated from the musical source signal instead of from the impulse response. Preliminary investigations showed that the IALF, calculated from simulated sound fields generated by ODEON, changed relatively the same for different pieces of music across various halls. If IALF is a valid measure for spatial impression, then this indicates that the musical source is not critical in evaluating the difference in spatial impression between halls. In this paper, results from subjective listening tests are presented to determine if the same trend is perceived by listeners across different musical motifs, which would aid in validating IALF.

Subjective relevance of objective measures for spatial impression

Several objective measures have been proposed to describe the feeling of spatial impression in concert halls, including Lateral Energy Fraction (LF) and Interaural Cross-Correlation Coefficient (IACC). However, previous studies have shown that LF and IACC values did not highly correlate with each other at individual seat positions in real halls [J. S. Bradley, J. Acoust. Soc. Am. 96, 3525–3535 (1994)]. To investigate the listener envelopment aspect of spatial impression further, subjective paired-comparison tests have been run using signals which have various values for LF, early IACC (from 5–80 ms), late IACC (from 80 ms–1 s), and late lateral relative sound level (GLL). Another proposed measure, called Interaural Level Fluctuations (IALF), has also been included, which is based on the rate of change over time of the level difference between the ears. The binaural test signals were generated by the room acoustics simulation program ODEON, using four different musical motifs, and were presented to test subjects via headphones. Results from the experiments are presented. [Work supported by ASA Hunt Postdoctoral Research Fellowship.]

Acoustical characteristics of a 360-degree surround hall

Boettcher Hall in Denver is a large multipurpose hall with audience seating completely surrounding the stage and has been described as a 360-deg surround hall. Extensive acoustical measurements were carried out to evaluate the characteristics of this hall configuration and to compare it to other halls of more conventional design. Impulse response measurements were made for the 45 combinations of three on-stage source positions and 15 receiver positions distributed throughout the audience seating area. The setup of the hall was representative of a typical unoccupied concert configuration. Measured parameters included octave band values of: reverberation times, early decay times, relative sound levels, and early/late sound ratios. Various measures of spatial impression were also measured including: lateral energy fractions, inter-aural cross correlations, and the newly proposed measure of listener envelopment, the late lateral sound level. Hall average values as well as the spatial variation of acoustical measures are compared to data obtained from a number of other halls. [Work supported by the Concert Hall Research Group.]

Effects of an audience and variable architectural features on the acoustics of Boettcher Concert Hall

Acoustic parameters (including reverberation time, early decay time, relative sound level, early to late sound ratios, lateral energy fraction, and interaural cross correlation) have been measured in Boettcher Concert Hall. All parameters were measured using different settings of variable architectural features such as acoustic drapes, variable height overhead stage reflectors, and movable stage towers. The monaural parameters were also measured with and without an audience. The effects of the variable features on the acoustic parameters are assessed. The effects of the audience on some of the acoustic parameters have been estimated using standard calculation methods. Calculated differences are compared to those actually measured in the hall. [Work supported by the Concert Hall Research Group.]

The sound level of the singer's formant in professional singing.

The relative sound level of the "singer's formant," measured in a 1/3-oct band with a center frequency of 2.5 kHz for males and of 3.16 kHz for females, has been investigated for 14 professional singers, nine different modes of singing, nine different vowels, variations in overall sound-pressure level, and fundamental frequencies ranging from 98 up to 880 Hz. Variation in the sound level of the singer's formant due to differences among male singers was small (4 dB), the factors vowels (16 dB) and fundamental frequency (9-14 dB) had an intermediate effect, while the largest variation was found for differences among female singers (24 dB), between modes of singing (vocal effort) (23 dB), and in overall sound-pressure level (more than 30 dB). In spite of this great potential variability, for each mode of singing the sound level of the singer's formant was remarkably constant up to F0 = 392 Hz, due to adaptation of vocal effort. This may be explained as the result of the perceptual demand of a constant voice quality. The definition of the singer's formant is discussed.