Acoustic Characteristics Research Articles

Experiments of acoustic resonance and vibration mode of kotsuzumi using paper pipe, V-shape pendulum, and carbon paper

Abstract Kotsuzumi is a membranophone used in the traditional Japanese performing art of Noh. So far, there are few studies about kotsuzumi. In this study, to reveal the component of kotsuzumi’s sound, we experimentally verified the acoustic characteristics of kotsuzumi. Acoustic physics experiments were conducted using paper pipes, clay, pendulum, and carbon paper. Loudspeaker and microphone were used to produce and record sound, respectively. First, the characteristics of the acoustic resonance inside the difference cavity shapes of the bodies were measured. Second, vibration modes of the membrane and the body were measured. Finally, a professional performer played kotsuzumi to verify the measured acoustic characteristics. We found that a sound around 200 Hz was due to (0,1) mode of the front membrane of kotsuzumi, a sound around 800 Hz was due to the characteristics of the body as a resonator, and a sound around 1580 Hz was due to the vibration of the kotsuzumi’s body itself.

Correction: Sage et al. Hybridization of Acoustic and Visual Features of Polish Sibilants Produced by Children for Computer Speech Diagnosis. Sensors 2024, 24, 5360

In the original publication [...]

Effect of Abstract Phonemic Complexity on Mismatch Negativity Amplitude.

Mismatch negativity (MMN) reflects a preperceptual neurophysiological response that is generated subconsciously due to the interruption of a memory trace of ongoing sensory events in the environment. It has been widely used by researchers to understand complex perceptual mechanisms. Furthermore, it has been recommended as an objective tool to investigate disorders related to auditory cognition in hearing aid and cochlear implant users. Many researchers suggest that utilizing a larger acoustic difference between standard and deviant stimuli within the oddball paradigm will lead to a more robust MMN response. The purpose of the present study is to examine if increasing the abstract phonemic contrast between standard and deviant stimuli in the oddball paradigm leads to a more robust MMN response. Fourteen young female adults participated in the present study. To ensure that the MMN response was elicited by phonemic and not acoustic differences in the stimuli, a one-to-many ratio was created for the abstract phonemic features while controlling the acoustic features when designing the oddball paradigm as described by Phillips et al. (2000). MMN amplitude was measured at the Cz and Fz electrodes in two conditions, with two trials in each condition. In condition 1, the standards and deviants differed by one distinctive feature: voicing in trial 1 (/tӕ/ was standard and /dӕ/ was deviant) and place of articulation in trial 2 (/bӕ/ was standard and /dӕ/ was deviant). In condition 2, the standards and deviants differed across two distinctive features: voicing and place of articulation. In trial 1, /pӕ/ was standard and /dӕ/ was deviant; in trial 2, /dӕ/ was standard and /pӕ/ was deviant. MMN amplitudes elicited by two distinctive features were significantly larger than MMN amplitudes elicited by one distinctive feature (p < 0.001). Trials 1 and 2 in each condition showed no statistical difference, and they were repeatable and highly correlated. Recordings from the Cz and Fz electrodes showed no statistical difference and were highly correlated and similar in morphology. It is known in the literature that increasing acoustic complexity elicits a more robust MMN. The present study showed that this assumption can be extended to abstract phonemic complexity. Increasing the phonemic complexity by utilizing more distinctive features in the oddball paradigm increased the amplitude and robustness of the MMN.

Application of Pulse Gas-Discharge Electroacoustic Transducer for Non-Destructive Testing

This paper presents the results of a gas-discharge electro acoustic transducer of two configurations, operating on the basis of a pulsed discharge in air at atmospheric pressure. The influence of the electrode configuration on the acoustic characteristics of the transducer is considered. It is shown that a change in the volume of the discharge chamber and the inter electrode gap have a significant effect on the radiation intensity of the transducer. The features that arise when using open and closed type electro acoustic transducers in flaw detection problems are revealed. It is shown that an open type gas-discharge electroacoustic transducer is a sufficiently powerful broadband source of the excitation signal and has prospects for use in non-destructive testing. A closed type gas-discharge electroacoustic transducer has advantages when testing materials with special requirements for surface cleanliness or the magnitude of the applied external electric field.

Exploring Voice Acoustic Features Associated with Cognitive Status in Korean Speakers: A Preliminary Machine Learning Study

Objective: To develop a non-invasive cognitive impairment detection system using speech data analysis, addressing the growing global dementia crisis and enabling accessible early screening through daily health monitoring. Methods: Speech data from 223 Korean patients were collected across eight tasks. Patients were classified based on Korean Mini-Mental State Examination scores. Four machine learning models were tested for three binary classification tasks. Voice acoustic features were extracted and analyzed. Results: The Deep Neural Network model performed best in two classification tasks, with Precision-Recall Area Under the Curve scores of 0.737 for severe vs. no impairment and 0.726 for mild vs. no impairment, while Random Forest achieved 0.715 for severe + mild vs. no impairment. Several acoustic features emerged as potentially important indicators, with DDA shimmer from the /i/ task and stdevF0 from the /puh-tuh-kuh/ task showing consistent patterns across classification tasks. Conclusions: This preliminary study suggests that certain acoustic features may be associated with cognitive status, though demographic factors significantly influence these relationships. Further research with demographically matched populations is needed to validate these findings.

Effects of Thermal and Stress Cycles on the Mechanical Properties and Acoustic Emission Characteristics of Rocks

Abstract The surrounding rock of underground rock chamber is frequently affected by disturbance load and circulating temperature; it is meaningful to study the mechanical properties of surrounding rock under these conditions for the construction of a safe and effective underground chamber. This study investigates the mechanical properties, failure modes, and acoustic emission (AE) characteristics of basalt and sandstone under various pretreatments, including water saturation pretreatment (rock samples [SR]), rock samples subjected to cyclic temperature pretreatment (SR-CTT), rock samples subjected to cyclic loading pretreatment (SR-CLT), and rock samples subjected to combined cyclic loading and temperature pretreatment (SR-CTT-CLT). A series of uniaxial compression tests (UCTs) were conducted to analyze how these pretreatments affect the mechanical properties of basalt and sandstone. These two kinds of rock exhibit distinct failure modes, SR-CLT and SR-CTT-CLT make the failure of basalt change from inclined shear to X-shaped shear, while SR-CLT makes it turn into splitting. AE data reveal that basalt generally exhibits lower AE counts than sandstone, with the highest counts observed under SR-CTT-CLT. Energy analysis indicates that basalt accumulates more total energy (Et) and elastic energy (Ee) compared to sandstone, with different pretreatments affecting energy dissipation (Ed) and damage severity differently in each rock type. These findings contribute to understanding the complex interactions between pretreatment methods and rock behavior in engineering applications.

Perception of Familiar Second Language Accents and the Role of Linguistic Background

This study investigates the ability of listeners to categorize second language (L2) accents with high familiarity and examines how their linguistic background affects their categorization accuracy. The participants were first language (L1) Greek bilingual and multilingual listeners, who completed a task involving the categorization of talkers’ origins. After listening to samples of English (the listeners’ L2) and Greek-accented English, they assigned each sample to either England or Greece. Both bilingual and multilingual listeners showed accuracy above chance levels. This suggests among other findings that shared knowledge of the target language structure by both the talkers and listeners who speak the same L1 (i.e., Greek) and the use of common interlanguage patterns by the talkers may have aided in the easy identification of Greek-accented English by the listeners. Interestingly, multilinguals did not demonstrate higher accuracy than bilinguals in categorizing accents, indicating that the exposure advantage found in previous research may not apply when familiarity effects are strong. Another important finding was the better identification of Greek-accented English compared to English by the listeners; this provides evidence that listeners were more attuned to the acoustic features characteristic of the former accent. The findings carry theoretical and pedagogical implications for L2 acquisition and crosslinguistic speech perception.

TimbreSense: Timbre Abnormality Detection for Bel Canto with Smart Devices

With the rise of mobile devices, bel canto practitioners increasingly utilize smart devices as auxiliary tools for improving their singing skills. However, they frequently encounter timbre abnormalities during practice, which, if left unaddressed, can potentially harm their vocal organs. Existing singing assessment systems primarily focus on pitch and melody and lack real-time detection of bel canto timbre abnormalities. Moreover, the diverse vocal habits and timbre compositions among individuals present significant challenges in cross-user recognition of such abnormalities. To address these limitations, we propose TimbreSense, a novel bel canto timbre abnormality detection system. TimbreSense enables real-time detection of the five major timbre abnormalities commonly observed in bel canto singing. We introduce an effective feature extraction pipeline that captures the acoustic characteristics of bel canto singing. By applying temporal average pooling to the Short-Time Fourier Transform (STFT) spectrogram, we reduce redundancy while preserving essential frequency-domain information. Our system leverages a transformer model with self-attention mechanisms to extract correlation and semantic features of overtones in the frequency domain. Additionally, we employ a few-shot learning approach involving pre-training, meta-learning, and fine-tuning to enhance the system’s cross-domain recognition performance while minimizing user usage costs. Experimental results demonstrate the system’s strong cross-user domain recognition performance and real-time capabilities.

Frequency Tunable Film Bulk Acoustic Resonator Integrating PMN‐PT/FSMA Multiferroic Heterostructure for Flexible MEMS

AbstractFrequency tunable flexible piezo resonators exhibit significant potential for technological advances in wearable magnetic field sensing, futuristic wireless telecommunication devices, and flexible micro‐electromechanical systems. This study presents a multifunctional and flexible 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3(PMN‐PT)/Ni50Mn35In15 (Ni‐Mn‐In) multiferroic heterostructure‐based bulk acoustic wave (BAW) resonator fabricated over Kapton substrate. The fundamental resonance frequency (fR = 5.31 GHz) of the resonator is tunable with magnetic and electric fields. A significant change in resonance frequency (ΔfR) of 405 MHz has been achieved with 3.37 Hz nT−1 sensitivity using a direct current (DC) magnetic field of 1200 Oe, attributed to the delta‐E effect. The resonator displays a significant magnetic field tunability of 8.83%. Additionally, a substantial ΔfR of 360 MHz, 36 Hz µV−1 sensitivity and 6.78% tunability is attained with 10 V of DC bias voltage. The impact of magnetic field and DC bias voltage on the acoustic characteristics have been studied by fitting the resonance frequency curves with an equivalent modified Butterworth‐Van Dyke model. The fabricated BAW resonator exhibits outstanding flexibility with no discernible change in fR up to 2000 bending cycles. Such PMN‐PT/Ni‐Mn‐In‐based multiferroic BAW resonators displaying magnetic and electric field tunability are propitious for next‐generation flexible electronics and magnetic field sensors.

Articulatory precision from connected speech as a marker of cognitive decline in Alzheimer's disease risk-enriched cohorts.

Mild cognitive impairment (MCI) has been recognized as a possible precursor to Alzheimer's disease (AD). Recent research focusing on connected speech has uncovered various features strongly correlated with MCI due to AD and related dementias. Despite these advancements, the impact of early cognitive decline on articulatory precision has not been thoroughly investigated. This study introduced the phoneme log-likelihood ratio (PLLR) to assess the articulatory precision of speakers across different cognitive status levels and compared its effectiveness to existing well-studied acoustic features. The study utilized speech recordings from a picture description task, which included data from 324 cognitively unimpaired participants with low amyloid-β burden (CU, Aβ()), 47 cognitively unimpaired participants with high amyloid-β burden (CU, Aβ()), 69 participants with MCI, and 20 participants with dementia. Nine acoustic features were extracted from the speech recordings, covering three categories: speech fluency, speech pace, and articulatory precision. Welch's -test and Hedge's were adopted to assess their discriminative ability. A reduction in speech fluency and pace was observed among participants in the MCI and dementia groups. The PLLR shows large effect sizes in distinguishing between cognitively unimpaired participants with low Aβ burden and those diagnosed with MCI or dementia. Additionally, the test-retest reliability experiment indicated moderate repeatability of the features under study. The study reveals PLLR as a sensitive indicator capable of detecting subtle articulatory variations across groups, while also providing further support for the association between reduced articulatory precision and early cognitive decline.

Cyclical variations in acoustic features within the song sessions of humpback whales (Megaptera novaeangliae).

Song sessions produced by humpback whales recorded off the coasts of Hawaii and Colombia show recurrent patterns of acoustic variation across consecutive songs. Analyses of intra-individual variations within continuous song sessions revealed that songs consistently cycled through stages of acoustic complexity. At time scales spanning tens of minutes, cyclical variations likely reflected the diving behavior of singers. Changes over shorter time frames suggest that singing humpback whales may also systematically modulate the acoustic complexity of individual sounds during song production, both by gradually morphing units and by varying the number of times they repeat sound patterns. Comparable cycles were evident across years and populations. Cyclical variations within song sessions can reveal how much time and energy singers spend producing tonal versus frequency-modulated/broadband elements. Tonal components are generally more difficult to localize spatially but easier to detect over long distances, suggesting that singing humpback whales may dynamically vary sound production in ways that affect both sound transmission and auditory spatial processing. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A Comparative Study on Acoustic Characteristics of Methane and Tetrahydrofuran Hydrate-Bearing Sediments

Laboratory acoustic measurements of hydrate-bearing sediments serve as an important reference for the geological interpretation of seismic exploration data. Tetrahydrofuran (THF) hydrates are relatively easy to form with precise control of hydrate saturation, and they overcome the long time it takes for methane in sediments to form hydrate. However, when THF hydrates are used as a substitute for methane hydrate, their acoustic properties yield different results. This study reports the results of a series of laboratory experiments on the formation of methane and THF hydrate in quartz sand and the evaluation of their acoustic properties. It compares the experimental results with the results of calculations from micro-distribution models of the four hydrates using effective medium theory (EMT). Methane hydrate formed by the excess gas method has higher acoustic velocities than THF hydrate at 0–80% saturation, but at 80–100% saturation, the situation reverses, with THF hydrate having a higher wave velocity. The methane hydrate synthesis process follows a mixed micro-distribution, with grain coating predominating at low saturations, the pore-filling mixing mode dominating at medium saturations, and grain coating dominating at high saturations. In addition, THF hydrate has a slow-velocity growth at low saturation and is dominated by a pore-filling model and a load-bearing model at high saturation. We compared our experimental data with a compilation of similar published results to confirm their reliability and support our conclusions. Both hydrate types exhibit distinct micro-distributions across different saturations. Therefore, when testing the elastic characteristics of hydrate sediments, the distinct hydrate synthesis methods and micro-distribution should be considered, especially when using THF hydrate as an alternative to methane hydrate.

Speech-based personality prediction using deep learning with acoustic and linguistic embeddings

This study introduces a novel method for predicting the Big Five personality traits through the analysis of speech samples, advancing the field of computational personality assessment. We collected data from 2045 participants who completed a self-reported Big Five personality questionnaire and provided free-form speech samples by introducing themselves without constraints on content. Using pre-trained convolutional neural networks and transformer-based models, we extracted embeddings representing both acoustic features (e.g., tone, pitch, rhythm) and linguistic content from the speech samples. These embeddings were combined and input into gradient boosted tree models to predict personality traits. Our results indicate that personality traits can be effectively predicted from speech, with correlation coefficients between predicted scores and self-reported scores ranging from 0.26 (extraversion) to 0.39 (neuroticism), and from 0.39 to 0.60 for disattenuated correlations. Intraclass correlations show moderate to high consistency in our model’s predictions. This approach captures the subtle ways in which personality traits are expressed through both how people speak and what they say. Our findings underscore the potential of voice-based assessments as a complementary tool in psychological research, providing new insights into the connection between speech and personality.

From phenotype to phonotype: a comprehensive description of voice features of Cri du chat syndrome.

Genetic syndromes have been studied by extensive research allowing a better definition of their clinical manifestations, natural history, and etiopathogenetic mechanisms. Nevertheless, some relevant, but still unexplored aspects of these multisystemic conditions need to be clarified. One of these aspects is the characterization of the vocal production, especially in some genetic syndromes in which the distinctive voice is the hallmark of the syndrome (e.g., Cri du chat syndrome, CdCS). The aim of this study is to provide a detailed description of phonotype of patients affected by CdCS. We prospectively recorded and analysed acoustical features of three corner vowels [a], [i], and [u] and number listing from 1 to 10 of 29 patients with molecularly confirmed CdCS (age range 4-21 years; mean 11 ± 6; median 10 years). For perceptual analysis, the GIRBAS scale was completed. The acoustical analysis was performed through BioVoice software. When stratified by age and gender, in the older men subgroup the grade, roughness, and asthenia mean values are the highest for each vowel, when compared with values of the same parameters obtained in the other subgroups. Statistical analysis highlighted 26 significant differences: 38% (10) concern the sustained phonation of /a/, 27% (7) are related to /i/ whereas 19% (5) to /u/. Ratio1, Ratio2, VSA, and FCR were also significant. Conclusion: The voice production not only conveys linguistic and paralinguistic information but also can give information regarding the speaker's biological and clinical characteristics.

Supplemental Material for Cyclical Variations in Acoustic Features Within the Song Sessions of Humpback Whales (Megaptera novaeangliae)

Supplemental Material for Cyclical Variations in Acoustic Features Within the Song Sessions of Humpback Whales (Megaptera novaeangliae)

Influence of Free Surface on the Hydrodynamic and Acoustic Characteristics of a Highly Skewed Propeller

The noise analysis of a large-scale aquaculture vessel reveals that during its navigation, the primary equipment noise, particularly from the propeller, exerts a notable influence on the aquaculture environment for large yellow croaker. The free surface greatly impacts the noise performance of propellers, which is a significant factor affecting the fish’s habitat. This study adopts the numerical simulation method to analyze the hydrodynamic and acoustic characteristics of the E1619 propeller operating near the free surface. The open-water performance and noise calculations of the propeller are verified through experiments, and the effects of different immersion depths and advance coefficients on the propeller are explored. The results demonstrate that the free surface significantly affects the thrust, torque, and noise of the propeller, especially at shallow immersion depths and low advance coefficients. Surface wave pattern causes the instability and breakup of tip vortices, causing increased thrust and torque fluctuations, reduced efficiency, and significant overall sound pressure levels in the entire flow field. As immersion depth and advance coefficients increase, the interaction between tip vortices and the free surface weakens, wake vortex instability decreases, and noise levels gradually reduce. These analyses and conclusions can guide the design of next-generation propellers for aquaculture vessels to optimize performance near the free surface.

Acoustical features as knee health biomarkers: A critical analysis

Acoustical knee health assessment has long promised an alternative to clinically available medical imaging tools, but this modality has yet to be adopted in medical practice. The field is currently led by machine learning models processing acoustical features, which have presented promising diagnostic performances. However, these methods overlook the intricate multi-source nature of audio signals and the underlying mechanisms at play. By addressing this critical gap, the present paper introduces a novel causal framework for validating knee acoustical features. We argue that current machine learning methodologies for acoustical knee diagnosis lack the required assurances and thus cannot be used to classify acoustic features as biomarkers. Our framework establishes a set of essential theoretical guarantees necessary to validate this claim. We apply our methodology to three real-world experiments investigating the effect of researchers’ expectations, the experimental protocol, and the wearable employed sensor. We reveal latent issues such as underlying shortcut learning and performance inflation. This study is the first independent result reproduction study in acoustical knee health evaluation. We conclude by offering actionable insights that address key limitations, providing valuable guidance for future research in knee health acoustics.

Identification of Individual Cattle Using Vocalization Despite Intra-individual Variation in Acoustic Features

Identification of Individual Cattle Using Vocalization Despite Intra-individual Variation in Acoustic Features

Sustainable polyurethane biocomposite foams by improved microstructure, acoustic characteristics, thermoregulation performance and reduced CO2 emission through phase change material integration

In this research, phase change material (PCM) comprised of energy storage biocomposite materials were improved with raw materials obtained from renewable resources. Modified raw material was synthesized by epoxy castor oil (ECO). After mixing the obtained modified castor oil (MCO) and polyether polyol, PCM of capric acid (CA) was supplemented. To initiate the chemical reaction, a certain amount of methylene diphenyl diisocyanate (MDI) was added to the mixture to provide cross-linking. The physical and chemical properties of the resulting biocomposite foams (BCF) were characterized. According to the results obtained, mixing MCO into polyether raw material increased the number of closed pores in BCF resulting in more CA stored in BCF cells produced. The use of MCO in BCF materials increased the CA integration ratio to 68 wt%. The melting enthalpy value of the novel BCF-PCM composites has been determined as 121.43 J/g. In a warm environment, the PCM additive creates a temperature difference exceeding 6 °C, while in a cold environment, it provides a cooling effect close to 6 °C. A more than 50 % improvement in thermal conductivity was achieved with 68 wt% PCM addition compared to pure BCF. The addition of PCM caused a reduction in tensile stress and strain values to an acceptable level. BCFs with PCM additives exhibit a sound absorption coefficient of 0.9 in narrow frequency ranges, whereas, in broad frequency ranges, this value was more than 0.7. In cold weather conditions, employing BCF-PCM material instead of traditional EPS material with a thickness of 0.1 m has led to at least a 30 % drop in CO2 emissions, no matter the type of fuel used for heating. When opting for BCF-PCM materials, the necessary heat demand was approximately 33 % less compared to using the same thickness of EPS in cold climates.

Dynamic reaction of slag-based geopolymer with brick powder: insights from acoustic emission, heat flow, and relaxation characteristics

Fractal dimension, heat, and NMR relaxation characterizations were employed to monitor the dynamic geopolymerization process of slag-based geopolymer (SBG) with brick powder (BP) in this research. Introducing 30% BP to SBG resulted in a delay of 6minutes in the occurrence of polymerization peak, with a 24.12% decrease in heat peak value. Furthermore, during the rapid polymerization phase, the time of the gel formation in SBG containing 30% BP was reduced by 34.18%, accompanied by a 20.91% decrease in gel water content. The sequence of AE parameters associated with early-age geopolymerization reaction has good fractal characteristics, with fitting coefficient greater than 0.95. Importantly, the heat flow curve, water evolution, and corresponding fractal dimension curves have good correspondence at 0-3h. Especially, the dissolution peak and polymerization peak of the heat flow curve basically coincide with the fractal dimension curve. The fractal dimension not only serves as an effective indicator for evaluating the geopolymerization process but also compensates for the limitations of calorimetry in characterizing reaction processes with relatively small particle migration and local heat release.