Sound Reception Research Articles

Validated 3D finite-element model of the Risso’s dolphin (Grampus griseus) head anatomy demonstrates gular sound reception and channelling through the mandibular fats

Like other odontocetes, Risso's dolphins actively emit clicks and passively listen to the echoes during echolocation. However, the head anatomy of Risso's dolphins differs from that of other odontocetes by a unique vertical cleft along the anterior surface of the forehead and a differently-shaped lower jaw. In this study, 3D finite-element sound reception and production models were constructed based on computed tomography (CT) data of a deceased Risso's dolphin. Our results were verified by finding good agreement with experimental measurements of hearing sensitivity. Moreover, the acoustic pathway for sounds to travel from the seawater into the dolphin's tympanoperiotic complexes (TPCs) was computed. The gular reception mechanism, previously discovered inDelphinus delphisandZiphius cavirostris, was also found in this species. The received sound pressure levels and relative displacement at TPC surfaces were compared between the cases with and without the mandibular fats or mandible. The results demonstrate a pronounced wave-guiding role of the mandibular fats and a limited bone-conductor role of the mandible. For sound production modelling, we digitally filled the cleft with neighbouring soft tissues, creating a hypothetical 'cleftless' head. Comparison between sound travelling through a 'cleftless' head vs. an original head indicates that the distinctive cleft plays a limited role in biosonar sound propagation.

Sound reception and hearing capabilities in the Little Penguin (Eudyptula minor): first predicted in-air and underwater audiograms.

Despite increasing concern about the effects of anthropogenic noise on marine fauna, relevant research is limited, particularly in those inaccessible species, such as the Little Penguin (Eudyptula minor). In this study, we collected freshly deceased Little Penguins for dissection and micro-computed tomography (microCT) scans. The head structures, including the ear apparatus, were reconstructed based on high-resolution imaging data for the species. Moreover, three-dimensional finite-element models were built based on microCT data to simulate the sound reception processes and ear responses to the incident planar waves at the selected frequencies. The received sound pressure fields and motion (i.e. displacement and velocity) of the internal ear-related structures were modelled. The synergistic response of ear components to incident aerial and underwater sounds was computed to predict the hearing capabilities of the Little Penguins across a broad frequency range (100 Hz-10 kHz), both in air and under water. Our predicted data showed good agreement with other diving birds in both the form and range of auditory sensitivity. This study demonstrates a promising method to study hearing in other inaccessible animals. The outputs from this study can inform noise impact mitigation and conservation management.

Do belugas send sound cues? -Experimental verification of blindfolded imitation among beluga-

Dolphins are able to successfully coordinate their behavior using audio signals. Therefore, the current study tested whether or not belugas can use sound to exchange information in a cooperative task and verified the mechanisms of the transmission of information during trials. The subjects are two male belugas, Nack and Duke. Nack was trained to rotate its body when the experimenter turns a hand in a circular motion (rotation cue) or to take a vertical position on the spot of the pool when the experimenter turned on a light toward the subject (headstand cue). Duke was required to do the same behavior as Nack but was blindfolded. During the test trials, the experimenter presented both cues toward Nack in random order. The result indicated that Nack responded correctly to both cues, and Duke behaved similarly to Nack. Moreover, Nack emitted different sounds in response to the cues, which indicates that Nack spontaneously transmitted information to Duke by emitting sounds, which led Duke to provide correct responses. Although Duke displayed the same behaviors as Nack did despite the lack of training to do so, Duke’s performance was due to learning by hearing sounds instead of training.

Functional plasticity of the swim bladder as an acoustic organ for communication in a vocal fish.

Teleost fishes have evolved a number of sound-producing mechanisms, including vibrations of the swim bladder. In addition to sound production, the swim bladder also aids in sound reception. While the production and reception of sound by the swim bladder has been described separately in fishes, the extent to which it operates for both in a single species is unknown. Here, using morphological, electrophysiological and modelling approaches, we show that the swim bladder of male plainfin midshipman fish (Porichthys notatus) exhibits reproductive state-dependent changes in morphology and function for sound production and reception. Non-reproductive males possess rostral 'horn-like' swim bladder extensions that enhance low-frequency (less than 800 Hz) sound pressure sensitivity by decreasing the distance between the swim bladder and inner ear, thus enabling pressure-induced swim bladder vibrations to be transduced to the inner ear. By contrast, reproductive males display enlarged swim bladder sonic muscles that enable the production of advertisement calls but also alter swim bladder morphology and increase the swim bladder to inner ear distance, effectively reducing sound pressure sensitivity. Taken together, we show that the swim bladder exhibits a seasonal functional plasticity that allows it to effectively mediate both the production and reception of sound in a vocal teleost fish.

Radio and Music Listening Practices in Colonial Mozambique: The Goan Experience

ABSTRACT In this article, I explore the role of radio and music listening practices in re-signifying the imperial identities of the population of Goan origin, who were either born in or migrated to colonial Mozambique. Apart from relying on archival research and interviews with radio professionals and other relevant informants, I also draw on 11 in-depth interviews with Portuguese and Mozambicans of Goan origin who have lived in colonial Mozambique for ten or more years, both men and women. Alongside the biographical method, I also examine my interlocutors’ relationship with several forms of media to investigate their past practices of radio reception and music listening. I articulate Nick Couldry’s framework of media as practice with Elizabeth Bird’s approach to the historical audience to understand my interlocutors’ memories of radio and sound reception as part of a broader set of social and cultural practices through which their imperial identities are reconstructed. The research results suggest that my interlocutors’ past radio and music listening practices contributed to both reproducing and discontinuing their parents’ socio-cultural practices brought with them when they migrated from Goa to Mozambique. Additionally, such practices enabled the construction of different ambivalent forms of Goan-ness in colonial Mozambique, hence across different spaces of the empire.

Fish hearing revealed: Do we understand hearing in critical fishes and marine tetrapods.

Hearing evolved in lampreys with a frequency range of 50-200 Hz. This hearing range is comparable to that of elasmobranchs, most non-teleosts, and lungfish. Elasmobranchs most likely use the saccule and the papilla neglecta (PN) for hearing. In non-teleosts and teleosts, lungfish, and certain tetrapods the saccule is the likely sensor for sound reception while the lagena and the PN are important for gravistatic sensing. Coelacanth and most tetrapods have a basilar papilla (BP) for hearing. In coelacanth and tetrapods, the hair cells of the BP are in contact with a basilar and a tectorial membrane. These membranes transmit mechanical vibrations. A cochlear aqueduct (CA) provides a connection between the cerebrospinal fluid that has a sodium rich space in coelacanth and tetrapods while the potassium rich endolymph is known in vertebrates. A unique feature is known in basic sarcopterygians, the intracranial joint, that never developed in actinopterygians and has been lost in lungfish and tetrapods. The BP in coelacanths is thought to generate pressure with the intracranial joint that will be transmitted to the CA. Lungs or a swim bladder are not forming in Chondrichthyes, structures that have a major impact on hearing in teleosts and tetrapods.

Reception and Makings of African Vocal Ensemble Sounds beyond Binaries

Abstract Since 1877, the Seventh-day Adventist (SDA) Church from North America has established its presence in Southern Africa. As with missionization in other denominations, this introduced a variety of primarily Euro-American musical influences into African religious practices. Over the years, Adventist musicians have constantly negotiated a complex relationship to their African contexts, often yielding musical outcomes that cannot be reduced simply to an indigenous vs exogenous or ‘African’ vs ‘Western’ binary evaluation. This intersectional phenomenon is not thoroughly explored in the current scholarship on SDA music. This paper provides background and details on collaborations and exchanges in various repertoires since the 1980s. I argue that these embody intersectional ideas that emerge beyond geographical, cultural, and chronological boundaries. The study is developed from analyzing unstructured interviews and audio recordings to illustrate perpetually blurred boundaries in musical practices that have conventionally distinguished “African” vocal sound.

A wide field-of-hearing metalens for aberration-free sound capture

Metalenses, as a designer tool for manipulating waves, has demonstrated remarkable capabilities thus far. However, their performance is limited to normal incidence and they exhibit significant sensitivity to oblique incidence. This sensitivity often leads to a decrease in focusing efficiency due to coma aberration, posing a considerable challenge. Here, we present a novel solution in the form of a wide field-of-hearing (FOH) metalens, specifically designed for capturing and focusing sound without aberration. To overcome the limitations of conventional metalenses, we propose a hybridized metalens that combines Helmholtz and zigzag building blocks. By incorporating both complete phase modulation and unitary transmission, this hybrid metalens achieves superior performance. We conduct experimental validations to demonstrate the proof-of-concept sound reception, thereby introducing the concept of wide FOH monitoring systems. The rational design of this metalens holds great versatility and can be implemented across various platforms. Its applications potentially span diverse fields such as energy harvesting, monitoring, sensing, imaging, and communication in auditory and submerged environments.

Finite-element modeling on noise impacts and hearing in marine fauna

Despite increasing interest in the effects of anthropogenic noise on marine fauna, relevant research is limited, particularly in those inaccessible species. Unfortunately, some of these inaccessible species are endangered, such as the little penguins (Eudyptula minor) and Australian sealions (Neophoca cinerea). In this study, we collected freshly deceased bight redfish (Centroberyx gerrardi), little penguins, and Australian sealion for medical computed tomography (CT)/microCT scans. Ear structures were reconstructed based on high-resolution imaging data for the three species. Moreover, 3D finite-element models were built to simulate the sound reception processes and ear responses to the incident planar waves from various directions toward the heads. The received sound pressure levels and motion (e.g., displacement and acceleration) of the internal ear related structures were computed. The data was used to predict the absolute hearing curves of the little penguins and Australian sealions. Our results also indicate that the motion difference plus the geometry of the otoliths plays an important role in the fish otoliths' response to incident sounds from different directions, resulting in different levels of damage to the hair cells. This study may potentially aid researchers in investigating the hearing of some other marine animals.

Sound Reception in the Yangtze Finless Porpoise and Its Extension to a Biomimetic Receptor.

Sound reception was investigated in the Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) at its most sensitive frequency. The computed tomography scanning, sound speed, and density results were used to develop a three-dimensional numerical model of the porpoise sound-reception system. The acoustic fields showed that sounds can reach the ear complexes from various pathways, with distinct receptivity peaks on the forward, left, and right sides. Reception peaks were identified on the ipsilateral sides of the respective ears and found on the opposite side of the ear complexes. These opposite maxima corresponded to subsidiary hearing pathways in the whole head, especially the lower head, suggesting the complexity of the sound-reception mechanism in the porpoise. The main and subsidiary sound-reception pathways likely render the whole head a spatial receptor. The low-speed and -density mandibular fats, compared to other acoustic structures, are significant energy enhancers for strengthening forward sound reception. Based on the porpoise reception model, a biomimetic receptor was developed to achieve directional reception, and in parallel to the mandibular fats, the silicon material of low speed and density can significantly improve forward reception. This bioinspired and biomimetic model can bridge the gap between animal sonar and artificial sound control systems, which presents potential to be exploited in manmade sonar.

A porpoise-inspired receptor to enhance broadband sound reception

Odontocetes have developed a broadband sound reception system that performs well underwater. We used aluminum materials and soft silica gels to fabricate a bio-receptor to mimic the sound reception system of a finless porpoise. Both numerical modeling and experiments suggested that compared to omnidirectional reception, the porpoise-inspired receptor can achieve broadband and directional sound reception with frequencies ranging from 15 to 90 kHz and enhance the reception by an average of 3.9 dB in this bandwidth. At some frequencies, this reception improvement can reach 7.3 dB in experimental data. This work provides an alternate idea to design sound receptors to be applied in underwater broadband and directional sound reception.

Sound detection and production mechanisms in aquatic decapod and stomatopod crustaceans.

The sensory systems of crustaceans (aquatic decapods and stomatopods) have adapted to a diverse range of aquatic ecosystems. Sound production in aquatic crustaceans is more widespread than previously thought, and has been shown to play a major role in many of their life-history strategies; however, there are still many gaps in our understanding of their sound reception abilities. Crustaceans have three main sensory receptors for sound - the statocyst, superficial hair cells and chordotonal organs - which are all sensitive to the particle motion component of the sound field, rather than the pressure component. Our current understanding of these receptors is that they are sensitive to low-frequency sounds (<2000 Hz). There are a wide variety of sound-producing mechanisms employed by these animals, ranging from stridulation to implosive cavitation (see Glossary). These signals are used for a range of social behaviours, such as courtship, territorial defence and assessing 'resource guarding'. Furthermore, there are examples of sound signals that exceed their hearing range, highlighting a mismatch in our understanding of their hearing systems. This mismatch provides weight to the suggestion that another sound transmission channel - substrate-borne vibrations - might be at play, particularly because most crustaceans live on or near the seafloor. Finally, suggestions are made regarding potential future work that is needed to fill the substantial gaps in our understanding of how crustaceans hear and produce sound.

Does rotation increase the acoustic field of view? Comparative models based on CT data of a live dolphin versus a dead dolphin

Rotational behaviour has been observed when dolphins track or detect targets, however, its role in echolocation is unknown. We used computed tomography data of one live and one recently deceased bottlenose dolphin, together with measurements of the acoustic properties of head tissues, to perform acoustic property reconstruction. The anatomical configuration and acoustic properties of the main forehead structures between the live and deceased dolphins were compared. Finite element analysis (FEA) was applied to simulate the generation and propagation of echolocation clicks, to compute their waveforms and spectra in both near- and far-fields, and to derive echolocation beam patterns. Modelling results from both the live and deceased dolphins were in good agreement with click recordings from other, live, echolocating individuals. FEA was also used to estimate the acoustic scene experienced by a dolphin rotating 180° about its longitudinal axis to detect fish in the far-field at elevation angles of −20° to 20°. The results suggest that the rotational behaviour provides a wider insonification area and a wider receiving area. Thus, it may provide compensation for the dolphin’s relatively narrow biosonar beam, asymmetries in sound reception, and constraints on the pointing direction that are limited by head movement. The results also have implications for examining the accuracy of FEA in acoustic simulations using recently deceased specimens.

Numerical simulations on the performance of optical-acoustic sensors of minimal dimensions

This paper presents analytical and numerical methods for developing optical-acoustic transducers of minimal dimensions. One can find acoustic sensors used as microphones in various electronic devices such as smartphones or smartwatches. Therefore, it is highly desirable to minimize their size while ensuring high-quality sound reception. The optical-acoustic sensor relies on laser detection of membrane vibrations and consists of a membrane that vibrates in the presence of an acoustic field and reflects the radiation emitted by the laser back to the laser. We focus on methods to optimize the membrane's design and the cavity (back volume) that separates the laser from the membrane. The back volume compliance significantly affects the sensitivity of the membrane. In addition, it is a noise source due to acoustic and viscous damping. Using calculations and simulations, we show the possibilities of reducing the membrane size and the air-filled back volume size while achieving the desired acoustic properties. We employ analytical calculations for the mechanical vibration of the diaphragm, back-volume compliance and resistance, and precise FEM simulations of the interaction between membrane vibration and the acoustic field. We build on similar techniques used for micromachined capacitive microphones, but we apply these methods newly to a specific setup of backplate-less optical-acoustic sensors. Based on the theoretical results, we can conclude that optical-acoustic devices achieve the same maximum noise level with smaller dimensions than the current industry standard.

The huaka‘i of Hawaiian monk seal Kekoa: Conservation through sound science

The Hawaiian monk seal (Neomonachus schauinslandi) is an endangered marine mammal and the subject of significant conservation concern. Limited bioacoustic information was available for this species until recently. The adult male Hawaiian monk seal Kekoa (KE18) was removed from the wild after repeated problematic interactions with conspecifics; he was then transferred temporarily to UC Santa Cruz, where he participated in studies to increase understanding of monk seal auditory biology. Compared to other seals, Kekoa’s behavioral hearing data suggest that monk seals have less sensitive hearing and a reduced functional frequency range of hearing in air and under water. A year-round characterization of his spontaneous underwater vocalizations revealed at least six low-frequency call types with a simultaneous peak in calling behavior and testosterone levels during the breeding season. Kekoa’s huaka‘i, or journey, has provided the first description of underwater communication for this protected species and contributed much-needed perspective about amphibious hearing abilities. Kekoa’s work has also inspired ongoing research with captive and wild individuals to confirm species-level traits in sound reception and production. These efforts have applications to studies of free-ranging monk seals through passive acoustic monitoring, development of automated call detectors, and the use of multi-sensor biologging devices.

Hearing is believing: Lexically guided perceptual learning is graded to reflect the quantity of evidence in speech input

There is wide variability in the acoustic patterns that are produced for a given linguistic message, including variability that is conditioned on who is speaking. Listeners solve this lack of invariance problem, at least in part, by dynamically modifying the mapping to speech sounds in response to structured variation in the input. Here we test a primary tenet of the ideal adapter framework of speech adaptation, which posits that perceptual learning reflects the incremental updating of cue-sound mappings to incorporate observed evidence with prior beliefs. Our investigation draws on the influential lexically guided perceptual learning paradigm. During an exposure phase, listeners heard a talker who produced fricative energy ambiguous between /ʃ/ and /s/. Lexical context differentially biased interpretation of the ambiguity as either /s/ or /ʃ/, and, across two behavioral experiments (n = 500), we manipulated the quantity of evidence and the consistency of evidence that was provided during exposure. Following exposure, listeners categorized tokens from an ashi – asi continuum to assess learning. The ideal adapter framework was formalized through computational simulations, which predicted that learning would be graded to reflect the quantity, but not the consistency, of the exposure input. These predictions were upheld in human listeners; the magnitude of the learning effect monotonically increased given exposure to four, 10, or 20 critical productions, and there was no evidence that learning differed given consistent versus inconsistent exposure. These results (1) provide support for a primary tenet of the ideal adapter framework, (2) establish quantity of evidence as a key determinant of adaptation in human listeners, and (3) provide critical evidence that lexically guided perceptual learning is not a binary outcome. In doing so, the current work provides foundational knowledge to support theoretical advances that consider perceptual learning as a graded outcome that is tightly linked to input statistics in the speech stream.

The Method of Soundscape Naturalness Curves in the Evaluation of Mountain Trails of Diversified Anthropopressure—Case Study of Korona Beskidów Polskich

Sound in the landscape is an element of the multisensory experience of the environment. In areas that are naturally valuable and additionally used for tourism, the quality of this element is much more important than in urban areas. The aim of the study was to assess the soundscape diversity of mountain trails included in the Crown of the Polish Beskids (Korona Beskidów Polskich). Two methods were used in the study: The first was sound intensity measurement using a sonometer, which provided information on the physical aspect of the landscape. The second method involved recording all sounds divided into two basic categories: anthropogenic and natural. These results made it possible to propose a new method for assessing the naturalness of the soundscape by plotting naturalness curves. In contrast to frequently used survey-based methods, in this method we minimise subjectivity, which is mainly due to the different perceptions of sounds by the assessors. Given how many psychophysical aspects can affect the reception and perception of sounds, the method of naturalness curves allows for a universal assessment of landscape quality. On all the mountain trails surveyed, the average sound intensity values exceeded 40 dB, which the authors considered to be borderline for areas of natural value and recreational use. In the study area, the influence of anthropopression on soundscape formation was found to be diverse and dependent on many factors. However, there was no clear evidence that tourism was the main negative influence. The plotted naturalness curves showed a large variation between trails, but not all trails showed a correlation between this parameter and the number of tourists on the trail.

Ośrodkowe zaburzenia przetwarzania słuchowego u dzieci w wieku szkolnym w świetle uczenia (się) języka angielskiego

Central auditory processing disorders are defined as deficits in the neural processing of auditory information in the central auditory nervous system with simultaneous normal hearing. Due to the inappropriate reception of speech sounds and difficulties in their understanding and reproduction, pupils may have difficulties in learning language, e.g. in earning and remembering vocabulary and pronouncing words correctly which may cause incorrect communication result or even lack of it. It is also worth mentioning that a great number of parents report difficulties in learning foreign language/languages in their children with central auditory processing disorders, especially English. Additionally, there are few studies discussing the topic of learning and teaching a second language among students with central auditory processing disorders. This paper aims to provide the importance and brief characteristics of central auditory processing disorders, as well as a review of the literature and results of questionnaire (about the foreign language learning difficulties) performed in 16 parents whose children were qualified to the listening training.

“Perchoo,” or the Music of Mourning

“Perchoo,” or the Music of Mourning

Remarks on the theory of hearing-a traveling wave part two

In the paper, attention was paid to the procedure of reception and transforming auditory information, which does not comply with Bekesy’s traveling wave theory. This concerns the sound reception below the hearing threshold in some animals and birds. Discussed are some issues related to the traveling wave theory with an explanation of directional hearing. Indicated was a possibility of reception, especially, of high frequencies, directly on the receptor, without the basilar membrane, due to the conduction of sound waves through soft tissues and a bone.