bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic conditions in innovative learning environments
Authors: ROBINSON Amanda
Published: October 2024

New generation or innovative learning environments are being developed in many OECD coun-tries, including Australia and New Zealand. These spaces are often criticized as being 'noisy', dis-tracting, unattenable, and yet, there has been a link between deep learning outcomes and the new
generation environments. Education spaces primarily revolve around speaking and listening activities. Although new space typologies have been, and continue to be, developed, the acoustic standards applied to them are often the same as those applied to traditional cellular classroom spaces.
This paper presents the results of systematic acoustic testing undertaken within numerous physical spaces for traditional and new generation learning environments in Australia and New Zealand, to compare the differences in performance between traditional cellular classrooms and open plan spaces,
and summarise any trends evident in the information. It also acknowledges the differences between traditional cellular spaces and new generation environments as determined from the results.
Wall sound insulation measurement in laboratory according to iso 10140-2 standard and sound insulation measurement on the same wall with electrical and telephone sockets
Authors: BAUTISTA KURI Antonio , PéREZ RUIZ Santiago Jesús
Published: October 2024

Study related to the measurement of acoustic insulation R to sand and cement block wall with flattening on both sides, which was built inside a Transmission Chamber in accordance with the ISO 10140-2 standard. Subsequently this wall is slotted, placing Conduits, accessories for illumination,
electrical and telephone sockets on both sides, finally covering all these installations with products that make it appear that the wall is intact, then the measurement of its acoustic insulation R and Rw is carried out. The results indicate variations that can be very annoying for residents
on both sides of the wall, highlighting the lack of sealing into the Conduits, the choice of materials, location of sockets and construction procedures, etc.
Attitudes and preferences of the Swiss population towards noise abatement measures: Results from a nationwide panel survey
Authors: BRINK Mark , GOMM Sarah , BRÜGGE Clara , BERNAUER Thomas
Published: October 2024

As part of the Swiss Environmental Panel (SEP) survey, conducted jointly by ETH Zurich and the Swiss Federal Office for the Environment (FOEN), we aimed at obtaining a representative picture of the Swiss people's attitudes regarding noise and noise sources as well as their opinions
and preferences about the currently implemented institutional noise protection measures. Knowledge of people's attitudes in this domain is very useful for policy makers, the public administration and the wider public. Survey topics included: degree of satisfaction with the current state of
noise abatement, annoyance by emerging new sources, the attitudes vis à vis speed reductions and other noise abatement measures at source, the reasons one is in favor or against these measures, the sanctioning of excessively loud car enthusiasts ("posers" as they are also
called), or the installment of "noise radars" to catch and punish noise offenders. Stratified analyses consider political and environmental orientation, age group, degree of urbanization, and socioeconomic status. Data gathering was carried out between May and August 2023 and involved
more than 7000 respondents across whole Switzerland.
Research on the application of second-order HR in attenuating tire cavity resonance noise
Authors: LIU Xiandong
Published: October 2024

Tire cavity resonance noise (TCRN) is well-known as one of the significant sources causing the interior noise at low-frequency band. Previous research shows that Helmholtz resonator (HR) array in an automotive wheel may obviously attenuate TCRN. To further improve the effect, the second-order
HRs in the HR array are introduced here. Firstly, the theoretical model of second-order HR is established, and the results are verified by finite element method. The results show that the second-order HR with the same cavity volume may produce two transmission loss peaks, and a higher peak
than that of the original first-order HR in the specified frequency band. Then, the optimization is performed to obtain a higher effect of attenuating TCRN at the original design frequency and a certain effect of attenuating road noise in the specified lower-frequency band. The results indicate
that the desired effect may be achieved, and the higher resonance frequency can easily fall in the frequency band below 600Hz although hard to fall in the frequency band of TCRN. So the second-order HR is helpful to improve attenuating road noise including TCRN.
Generalization of noise insulation afforded by common window designs with active noise control exposed to moving noise source
Authors: TAN Johann Kay Ann , LAU Siu-Kit
Published: October 2024

A window device that can provide noise insulation while maintaining natural ventilation is highly desirable and is especially sought after in heavily noise-polluted and hot-humid climates cities, such as Southeast Asian cities. However, a solution to provide such a window is non-trivial
because the design principles guiding acoustics and ventilation are diametrically opposed. While louvre windows have traditionally been used in communal, healthcare, and some educational setting to provide a balance between acoustics and ventilation benefits, it is still sorely lacking to
provide sufficient insertion loss without sacrificing ventilation entirely. A new plenum window design has recently garnered research and market interest to tackle the dichotomous problem. Additionally, the application of active noise control (ANC) in windows is gaining popularity and offers
potential solutions to improve noise control without compromising ventilation. However, it remains unclear how different traditional and modern window designs compare in terms of their acoustic performance, especially when exposed to non-stationary noise sources such as urban traffic, a major
noise pollutant. Thus, the present study seeks to provide a generalization of insertion loss provided by different window designs exposed to moving sources including a tangent study on ANC implementation via a time-domain approach.
Auditory time travel: Acoustic notes on the virtual reality reconstruction of the Queen's theatre (Adelaide, 1841)
Authors: CASTRO Daniel , HOLLEDGE Julie
Published: October 2024

This paper presents the results of an international interdisciplinary effort to reconstruct the Queen's Theatre in Adelaide as it stood on its inaugural debut in 1841. Our collaborative approach brings together real actors, set and costume designers, architects, virtual reality (VR)
developers, motion capture specialists, and acoustic engineers in order to reproduce, as realistically as possible, the opening night monologue by Mr Gustavus Arabin. By combining the modelled ambisonics room impulse responses with a proprietary algorithm, we achieved an authentic representation
of the historical environment both visually and acoustically by allowing the user to immerse themselves in the space at several locations within the theatre. Central to our VR reconstruction is the ability of our software to combine auralisations from multiple sound sources simultaneously
as well as allowing the user to upload user-generated anechoic files. The paper focuses on the acoustic nuances throughout the VR reconstruction, providing a comprehensive overview of collaborative endeavours and technological advancements enabling users to grasp and appreciate the acoustic
intricacies of Queen's Theatre. Emphasising the acoustic dimension of the space underscores the potential of our virtual model to serve as a dynamic platform for historical exploration, research, and educational pursuits.
Optimized position analysis of multi-directional active mounting system based on quantification formula
Authors: ZHOU Ziyue , QIU Yang , KIM Byeongil
Published: October 2024

This paper mainly studies the influence of active mounting system for vehicle engine vibration from both theoretical and experimental aspects. First, an active mounting system that considers both horizontal and vertical directions is proposed, modeled, analyzed and verified. The structure
contains a bent beam representing the engine, two sets of actuator and elastomer forming active paths, and a straight beam representing the chassis. Second, the force and phase of the active mounts at each location combination are calculated based on static and dynamic methods. The dynamic
analysis method is used to examine how the control signal changes with the input signal to learn the correlation between them. The static analysis is employed to obtain the change in force applied to the paths when the position of the input signal changes and to find the optimized placement
criteria. Through the position relationship between force and mounting, a specific position where the applied force is relatively small was considered the optimized position of the active mounting system. Finally, these criteria were verified with experiments and the results are matched well
with each other.
Noise reducing elements filled with laminated safety glass (LSG) for use along railway lines
Authors: WOJAN Immanuel , BöHM Jenny
Published: October 2024

The main purpose of noise barriers is to shield the environment from unwanted sound. Along railway lines, noise barriers must also meet strict requirements for structural integrity, usability and fatigue safety. Furthermore, noise barriers should satisfy aesthetic criteria. Transparent
noise barriers have less impact on the environment and are more widely accepted by the public. In Germany, PMMA (acrylic glass) is currently the only transparent material approved for railway noise reducing elements. Laminated safety glass (LSG) could be a viable alternative due to its high
rigidity and transparency, comparatively low dirt accumulation and high chemical and physical resistance. However, it still needs to be demonstrated that LSG meets the strict requirements for use along railway lines. LSG is a type of laminated glass that has a splitter-binding intermediate
layer of plastics. The multi-layered structure presents challenges regarding the proof of usability. MFPA Leipzig GmbH was commissioned by the German Centre for Rail Traffic Research at the Federal Railway Authority to develop and evaluate possible methods to prove the usability of LSG for
noise barriers along railway lines. The paper presents the structure of the project, the main findings until now and the open challenges to be addressed.
Comparison of traditional and deep learning optimisation for the design of acoustic metamaterials
Authors: OGUN Oluwaseyi , KENNEDY John
Published: October 2024

This paper presents a comparative analysis of traditional and Deep learning (DL) optimisation approaches for AMM design. A case study comparing a generalised pattern search (GPS) optimisation to a previously trained inverse design deep neural network (IDDNN) of an acoustic meta-absorber
using various metrics is considered. For benchmarking, a baseline design is realised with arbitrarily chosen geometric parameters in a CAD software. This design is 3D printed and experimentally tested. The peak absorption and corresponding resonant frequency obtained from experimental absorption,
along with other geometric parameters, are used as inputs to IDDNN and GPS. Results show that IDDNN provides superior inference speed, requiring 7.24e-3 [s] to generate predictions on a single input instance, compared to GPS which took about 30.5464 [s]. While GPS exhibits slightly closer
alignment to experimental curve based on Kullback-Leibler divergence (2.79e-3) compared to IDDNN (3.31e-3), IDDNN still achieves a slightly higher accuracy of 92%, compared to 90% for GPS. It is emphasised that trade-offs may be necessary in practice to determine the most suitable design approach
for a given application. Traditional optimisation offers ease of design flexibility, allowing for on-the-fly model improvement and modification. In contrast, DL may require re-training, leading to delays in process workflow
Study on frequency dependent convolution methods for sound event detection
Authors: NAM Hyeonuk , KIM Seong-Hu , KO Byeong-Yun , MIN Deokki , PARK Yong-Hwa
Published: October 2024

Sound event detection (SED) aims to classify target sound events from a given audio clip with the corresponding onset and offset time localization. SED, a core research field in machine listening, has been rapidly growing by adopting the methods by applying deep learning methods in
image recognition fields. One representative example is 2D convolution which is applied to 2D time-frequency audio features. However, 2D audio data exhibits physical discrepancies from 2D image data, one of which is that frequency dimension of 2D audio data is translational-variant while position
dimension of 2D image data is translational-invariant. Therefore, to make 2D convolution more consistent to 2D audio data, we need to make 2D convolution dependent to frequency dimension. Previously, to address this problem, Frequency Dynamic Convolution (FDYConv) was proposed to replaces
2D convolution. FDYConv is dependent on frequency dimensions since it applies different kernels on frequency dimension. While it has proven its outstanding performance on SED, there are several more alternative frequency dependent convolution methods which are yet to be explored, In this work,
we propose other simpler frequency dependent convolution methods and compare them with FDYConv in order to further investigate the effect of frequency dependence of 2D convolution methods.
Analytical modelling techniques for efficient broadband noise prediction of high-speed trains
Authors: LIU Xiang , ZHAO Xueyi
Published: October 2024

Analytical modelling techniques are presented for broadband noise prediction of high-speed trains. For interior noise problems, train body structures are modelled exactly by the dynamic stiffness method (DSM); whereas the interior acoustic cavities of the train body are modelled by
the SDSM where the boundary conditions are described by modified Fourier series with a rapid convergence rate. Finally, the vibro-acoustic coupling model of the train body structures is constructed. For exterior noise problems, exterior train noise models are first formed by experimental data
considering the Doppler effect; then both the DSM and theoretical attenuation formulas are used to build noise radiation models for different external environment conditions. The performance of the method is evaluated by predicting the interior sound field distribution of typical cross sections
of the train body and the external radiated noise in a tunnel, or in an environment where the acoustic barrier or buildings along railways exist. Numerical results are in good agreement with the those obtained by the finite element method. Thus, the proposed methods can achieve broadband noise
prediction highly accurately and efficiently, which can also serve as the benchmark for predicting the radiated noise generated by high‐speed trains.
Aircraft icing detection via flow-induced ambient random noise: from theory to wind tunnel experiments
Authors: WANG Xun , QIN Qihang
Published: October 2024

Aircraft icing is a serious threat to flight safety. This paper presents a passive approach to detect ice accreted on an airfoil using flow-induced random noise considering spatially-inhomogeneous transient excitations. Under the assumption of diffuse-field, by computing the cross-correlation
of ambient vibration measured at two receivers and band-pass filtering it, the guided wave dispersion curve of the structure can be well-reconstructed, by which one can estimate the ice thickness by matching the reconstructed dispersion curve with its theoretical model. In practice, however,
the diffuse-field assumption may not hold as spatially-inhomogeneous strong transient excitations exist. The associated directional wave propagation generates additional peaks in the cross-correlation and this contaminates the ice detection result. Therefore, this paper proposes a signal processing
technique to identify and suppress the contributions from the transient source in the measurements, by which a reliable dispersion curve reconstruction and an accurate ice detection can be retrieved. The proposed method is shown to be efficient via a wind tunnel experiment. The passive ice
detection method is specifically suitable for aircraft online monitoring because only passive sensors are needed which can be tiny, light, and mounted on the internal surface of fuselage skin without any influence on aircraft aerodynamics.
Assessment of angular distribution of sound scattering in enclosures
Authors: XIE Dingding , HORNIKX Maarten
Published: October 2024

This study proposes an approach for quantitatively assessing sound scattering degrees caused by objects within enclosures. It categorizes the high-frequency sound fields in rooms into two distinct components: (1) specular reflections arising from boundary surfaces, and (2) non-specular
scattering contributed by objects (interiors). To achieve this, sound fields sampled on a sphere for two scenarios, with and without interiors, were decomposed into plane waves. The coherence between the impulse responses of these plane waves for these two scenarios is analyzed to obtain the
proportion of specular and non-specular components within the room containing interiors. Derived from these coherence curves, the Equivalent Scattering Coefficients (ESCs) quantify the degree of scattering distributed across various directions, reflecting the interaction of sound waves with
these interior elements. The extracted ESCs facilitate to quantification of the proportion of specular and non-specular components, which can be efficiently modeled separately and combined in a hybrid acoustic model, offering significant potential for sound field reconstruction.
Marnkutyi Parirna Theatre - An acoustically adaptable theatre design
Authors: MACDONALD Jenna , GARCíA GóMEZ Juan Óscar , ROBINSON Amanda
Published: October 2024

Most schools will only embark on one significant arts complex in their lifetime. As with any space constructed for educational purposes, there is an appeal for accommodating a wide range of educational experiences and uses in that single space. This however often contrasts with venue
needs such as the acoustic design needs to accommodate multiple uses. Quality performance venues are typically acoustically fine-tuned for a single use as differing uses can have competing requirements. This can limit performance outcomes when designing a static space, which can leave schools
with theatres which are either great at one thing or mediocre at many... acoustically speaking. However, we aspired to deliver more than this for Trinity College. The role of the acoustician, theatre designer and architect became paramount to the venue's successful delivery. Achieving acoustic
excellence and aesthetic beauty for a creative space requires a holistic understanding of engineering, architectural design, and artistic vision. Flexibility and adaptability were key to the venue operation, as was ease of operation. This paper presents a case study that includes the combination
of music, art and science in the delivery of the 500-seat adaptable theatre known as the Marnkutyi Parirna Theatre in South Australia.
The crossover frequency of acoustic simulation for small-scale enclosures by wave and statistic based methods
Authors: WANG Ziyu , YU Guangzheng
Published: October 2024

In the field of room acoustic simulation, wave-based and statistical numerical methods are pivotal for acquiring sound field characteristics. Although the Schroeder Frequency has been utilized to deduce the suitable frequency range of these methods in large enclosures, the crossover
frequency warrants further investigation for the small-scale enclosures with complicated inner structures, such as car cabins. This work aims to explore the applicable frequency range of these acoustic simulation methods for a small-scale model, which means identifying the crossover frequency
between wave-based Finite Element Method (FEM) and statistical Ray Tracing Method (RTM). First, the crossover frequency was analyzed by the Schroder Frequency equation and modal density estimated from the room transfer functions (RTFs) in a simplified car model, which considering the interior
with and without seat occlusion. Further, the crossover frequency was validated by comparing the magnitude spectra of RTFs simulated by FEM and RTM. This work provides a foundational frequency reference for applying statistical acoustic methods in small-scale enclosures.
Evaluating on the spatial localization cues of binaural sound pressure recorded via behind-the-ear microphones in a hearing aid
Authors: DONG Runze , XIE Bosun , WANG Yewei , YU Guangzheng , MENG Qinglin
Published: October 2024

Spatial hearing ability enables people with normal hearing to localize a sound source and utilizes the cocktail party effect to detect the target speech information in a noise environment. Hearing-impairment causes not only hearing loss but also the degradation of spatial auditory ability.
Hearing aid is desired to improve the spatial auditory ability of some hearing-impaired people, in addition to compensating hearing loss. However, the microphones for conventional behind-the-ear (BTE) hearing aid are located behind the pinnae rather than in the entrances of ear canal, which
may cause distortion in spatial cues in the recorded binaural signals. The present work comprehensively evaluates the spatial hearing cues recorded by BTE-microphones. The head-related transfer functions (HRTF) for a KEMAR artificial head and eight human subjects, at three BTE positions and
the entrances of blocked ear-canal, are measured respectively. Analysis from the HRTF data indicates that BTE microphone recording basically reserves the interaural time difference and interaural level difference as lateral-direction information. It also reserves the dynamic cues, but obvious
distortions appear in the spectral cues at high frequencies. However, due to the redundancy among different spatial information, it can be inferred that dynamic cues alone may provide appropriate front-back and vertical-direction information.
Vibration annoyance due to turbulences in an airplane : subjective and physiological assessments
Authors: JIBODH-JIAOUAN Sarah , PARIZET Etienne , DELCOR Laurianne , OSMOND Guillaume
Published: October 2024

Turbulence phenomena in an aircraft create important vibrations, at frequencies of between 0.5 and 10 Hz. An experimental design was used to assess the influence of different signal parameters (frequency band, vertical and lateral vibration levels), and the task the participant in which
the participant was involved (resting, watching a movie on a tablet computer, working by typing and using the trackpad of a computer). Thirty-three participants were subjected to around twenty signals, each lasting 45 s, using a multi-directional excitation device available in Airbus facilities.
Physiological parameters (electrodermal activity, heart rate) were measured continuously. After each signal, the participant was asked to assess the discomfort of the situation. The results showed the influence of different signal characteristics or task assigned to the participant. As a general
rule, subjective assessments correspond to physiological measurements. The experiment revealed the influences of the signals physical factors and the task performed by the participant. Finally, the ISO2631 standard seems to provide a good representation of the subjective evaluation of discomfort
in the different configurations presented.
Uncertainty and sensitivity analysis of non-acoustic parameters on acoustic characteristics prediction models for porous foam materials
Authors: HE Yansong , LUO Xuhui , ZHANG Zhifei
Published: October 2024

Porous foam materials are widely used in noise control applications. Their acoustic performance can be predicted by acoustic models composed of non-acoustic parameters such as flow resistivity, porosity, tortuosity, viscosity, and characteristic length. However, the influence of these
parameters on model outputs varies across different frequency ranges. Therefore, when using a single model for predictions across the entire frequency range, parameters may not fully act within the frequency range where their influence is greatest. To reduce prediction errors and improve the
correlation between predicted numerical results and experimental data, uncertainty and sensitivity analyses can be conducted to determine the extent of each parameter's influence at different frequency ranges. In this study, polyurethane foam materials are investigated, and uncertainty and
sensitivity analyses are performed on two acoustic models. Firstly, the uncertainty of parameters is assessed using the Monte Carlo method. Secondly, Sobol index method is employed to reveal the influence of parameters across various frequency ranges. Finally, by comparing the results of both
analyses, the optimal frequency ranges for each parameter can be summarized. This provides valuable reference for enhancing the accuracy of acoustic model predictions.
Coupling model between building post structure and floors with the spectral element method
Authors: BRISSON Apolline , PERREY-DEBAIN Emmanuel , CHAZOT Jean-Daniel , COQUEL Guillaume , GUIGOU-CARTER Catherine , JEAN Philippe
Published: October 2024

With the densification of urban area and public transport, the structure-borne noise disturbance due to railway traffic is a major issue. In order to mitigate it, ground-borne vibration propagation in building has to be investigated. The case of post-beam constructions necessitates
3D modeling with choices between complex, precise and computationally time-consuming approaches (3D finite element method for example), and fast but less accurate approaches like the statistical energy analysis (SEA) which need a strong modal density. For such post-beam constructions, the
spectral element method (SEM) appears to be a good compromise. This method allows reducing the number of elements to represent the truss structure compared to the finite element method. However, the building walls and floor are difficult to consider with the SEM. In this paper, the challenge
of coupling post-beam structures and floors is examined, a method is proposed and results are discussed. The aim is to develop a method applicable to different buildings while keeping advantage of SEM low discretization.
On the sound attenuation of balconies
Authors: FJELD Øyvind
Published: October 2024

The use of local sound screening measures has become more relevant as urbanization and traffic in urban areas are increasing. Even though it is preferable to do screening measures near the sound sources, this is not always possible. The Norwegian guideline T-1442 allows for certain
apartments to have local sound screening measures to reduce sound levels outside of windows. One such screening measure is the use of a balcony to reduce sound levels at the façade. Measurements have been conducted at various balconies to determine reduction of road traffic noise and
compare the results to values given in ISO 12354-3:2017. The effect of relative balcony height, angles and balcony screening have been investigated.
Numerical evaluation of rail track noise and vibration and components optimization
Authors: NARDIN Raphaël , CUGNONI Joël
Published: October 2024

In the context of a project commissioned by the Swiss Federal Office for the Environment, an open-source modelling toolbox was developed to simulate and analyze rail tracks dynamics. In particular, a vibro-acoustic multi-sleeper model, which is based on advanced finite element modelling
techniques, was used to investigate the effects of components properties on track noise and vibration. Considering changes around a reference construction (60E2 rail, SBB hard pad, B91 sleeper), parametric studies were performed on the dominant parameters identified for the acoustic and ballast
protection performance indicators defined. The following sweet spot for the component properties of the track have been identified as using a rail pad of medium stiffness (1000 kN/mm at 1kHz, 300 kN/mm static stiffness) and high damping (at least 0.5) combined with soft Under Sleeper Pads
(250 kN/mm). Based on the present models, such combination could provide both a significant noise reduction and a marked improvement in ballast protection compared to current track construction.
A signal processing system for infrasound-based detection and tracking of tornadoes
Authors: FRAZIER William
Published: October 2024

It has been established that tornadic storms emit infrasound at infrasonic frequencies and that this sound can be detected from practically significant distances exceeding 100 km in some cases. This work describes a signal processing system that is used to ingest data from a network
of infrasound arrays and produce near real-time detections and ground tracks of multiple, simultaneously active tornadic storms. Specifically, a brief review of a particular array network and corresponding hardware is presented followed by detailed descriptions of the array signal processing
architecture and source geolocation system. Emphasis is placed on algorithms for multiple moving source acoustic source bearing tracking, low SNR signal detection, mitigation of errors created by anomalous acoustic events, and multiple-array data association. Performance results corresponding
to simulated and recorded data are presented.
Numerical study of acoustic metamaterial made of Helmholtz resonators with complex necks for low frequencies noise attenuation
Authors: LALY Zacharie , MECHEFSKE Christopher , GHINET Sebastian , KONE T. Charly , PANNETON Raymond
Published: October 2024

In this paper, an acoustic metamaterial consisting of Helmholtz resonators with complex necks is proposed for low frequency noise reduction. The resonators are made of a cavity and a complex neck, which is a periodic succession of necks with small and large diameters. The acoustic attenuation
performance of the proposed metamaterial design is demonstrated using finite element method. For such a shaped neck, the sound absorption coefficient presents multiple peaks. With a succession of N small and (N - 1) large neck diameters, N peaks in the sound absorption coefficient are obtained.
By increasing the number of successions, the number of peaks increases. At the peaks, the surface acoustic impedance of the metamaterial nearly matches with the characteristic impedance of the air. This makes the sound absorption coefficient being nearly 100%. Keeping the same cavity volume,
we increase the number of sound absorption peaks by the complex shape of the neck, while the classic Helmholtz resonator presents only one peak.
Noise sensitivity model- a qualitative investigation
Authors: WU Jiana , DIRKS Kim N , SHEPHERD Daniel , WELCH David
Published: October 2024

Noise sensitivity is a concept used to explain the different effects of noise on people's health. Numerous definitions of noise sensitivity have been proposed, though none are universally accepted. Hence, a "system model of noise sensitivity" was developed, suggesting that
noise sensitivity may contain a set of factors. Based on this, we conducted semi-structured interviews to investigate noise sensitivity and its factors and used qualitative research methods to analyse the data. More factors of noise sensitivity were discovered, and a revised system model was
developed. This expanded model provides a more complete definition of noise sensitivity. We hope the improved understanding could lead to identifying ways of coping with noise issues. In the future, more diverse and individualized approaches could be developed to address the many different
aspects of noise sensitivity.
Exploration of low-frequency broadband potential in three metamaterial configurations
Authors: YAN Snow
Published: October 2024

Low frequency broadband is still challenging for metamaterial design. This study delves into the exploration of low-frequency broadband potential within three distinct configurations. We explore the analytic sound absorption models for Helmholtz resonators, films and locally resonant
structure (membrane film with additional mass). The research investigates the capabilities and possibilities of achieving frequencies below 1000Hz for each configuration. Through a comprehensive analysis, the study aims to uncover the unique advantages and challenges associated with these
three setups, shedding light on their potential applications in diverse fields. We also perform related tests for each configuration. Test results confirm the analytical models but they also highlight the benefits and drawbacks of various configurations. These findings provide valuable insights
into the understanding of low-frequency broadband technology and pave the way for further advances in related areas.
Random incidence absorption characteristics and parameterized design of micro-perforated panel absorbers with parallel-arranged backing cavities at different depths
Authors: ZHAO Yuchen , LOU Huading , RONG Ninging , MIN Hequn
Published: October 2024

Micro-perforated panel absorbers (MPAs) are recognized as efficient and environmentally friendly materials for sound absorption, prompting significant research efforts to expand their frequency ranges. This study investigates the acoustic performance of MPAs with parallel-arranged backing
cavities at different depths (PCD) under random incidence conditions. Initially, an analytical model is proposed to predict the acoustic performance of PCD-MPA. The model exhibits significant consistency with finite element simulations and experimental measurements, validating its reliability
in calculating absorption coefficients within the primary frequency band of concern (500~4000 Hz) in architectural acoustics applications. Subsequently, a thorough discussion of the key parameters, including the depth sequence and perforation parameters, which influence the random incidence
absorption characteristics of PCD-MPA is presented based on the proposed model. These discussions lead to the development of an enhanced parameterized design method aimed at improving the absorption performance of PCD-MPA, enabling precise modulation of parameter combinations to meet specific
application requirements and design nearly perfect absorbers.
Estimation of random incidence sound transmission loss of panels based on normal incidence sound transmission loss measurements
Authors: WANG Ziyang , GU Sheng , YUE Wenxuan , WANG Bo , MIN Hequn
Published: October 2024

The performance of building sound insulation is an important parameter for evaluating the quality of construction projects. So far, the sound insulation performance testing of building walls requires the installation of large-dimensioned wall samples in specialized sound insulation
laboratories, which is time-consuming and costly. If small-dimensioned components of the wall panels can be applied and quickly tested at the project site, it could significantly improve efficiency and reduce costs. To address this issue, this paper investigates a method for estimating the
random incidence sound transmission loss of wall panels based on the measurement of the normal incidence sound transmission loss of corresponding small samples. Initially, the sound transmission loss of single-layer and composite structures is theoretically analyzed based on the theories of
Equivalent Single Layer method and Layer-Wise method. Subsequently, the random incidence sound transmission loss is estimated by the normal incidence sound transmission loss. The methodology for estimating the random incidence sound transmission loss of wall panels proposed in this study offers
both a practical approach and theoretical support for the rapid assessment of the sound insulation performance of building walls. This study is of great significance for improving the quality of construction projects and inspection efficiency.
Feasibility of an acoustic liner applied to a Fenestron: simulation
Authors: SIMON Frank , SEBBANE Delphine , LAFONT Victor , PINACHO Jean-Paul , CAILLET Julien
Published: October 2024

A helicopter's anti-torque system is a significant contributor to radiated noise. The Fenestron, used on Airbus Helicopters, allows to mitigate the anti-torque noise by masking effect and modulation of the blade distribution. However, unlike aircraft engine nacelles, it does not contain
acoustic liners inside the duct to absorb the noise radiated by the rotor blades. This paper describes: first, the FEM modelization of the noise radiation for a 1/3-scale fenestron mock-up at the 1st BPFs, in static conditions; second, the assessment of the effect of an absorbing treatment
introduced inside the collector or the diffuser and defined by its acoustic specific impedance; third, the design optimization applied to different acoustic liner types, adapted to the diffuser of the mock-up. Because of the limited duct length, forward and afterward radiations interact, generating
interference pressure patterns. Several types of liners (conventional and unconventional), designed to deliver a high absorption, appear adapted to dimensional constraints: SDOF or DDOF type, with a perforated plate above cavities or based on the concept LEONAR ("Long Elastic Open Neck
Acoustic Resonator"). Another paper completes the study with (aero-)acoustic tests, applied to elementary samples to validate the impedance target, and performed in an anechoic room with the mock-up.
Prediction and analysis of interior sound quality of high-speed trains based on XGBoost
Authors: QIAN KUN , SHEN ZHENGHUA , TAN JING , WANG YANFU , LIU KE , XIKANG Du , JIYING Duan
Published: October 2024

This paper primarily investigates the objective quantification of subjective perceptions of sound quality in high-speed trains. The study measures and analyzes the sound quality in high-speed trains under high-speed operating conditions and calculates psychoacoustic parameters. A subjective
evaluation of the interior sound quality is conducted using the grading scale method. An Extreme Gradient Boosting (XGBoost) algorithm is utilized to construct a predictive model for sound quality in high-speed trains and get high predictive accuracy for sound quality evaluation. Employing
AI-based evaluation models to evaluate the sound quality in high-speed trains offers a more effective method for studying the interior sound quality of high-speed trains.
Sound quality characteristics of reciprocating hermetic refrigeration compressors
Authors: CATAK Nuri Onur , ARSLAN Ergin , LAZOGLU Ismail
Published: October 2024

In recent years, sound quality (SQ) has become an increasingly important factor in the home appliance industry, enhancing the customer experience and comfort. Manufacturers that prioritize SQ in their designs can gain a competitive advantage in the market and increase customer satisfaction.
The compressor is one of the main sources of noise in a refrigerator. While manufacturers typically provide refrigerator sound quality and noise labels, research that specifically evaluates the compressor sound quality metrics at a component level is not common. Therefore, this study aims
to isolate the compressor from the refrigerator to investigate SQ metrics for hermetic refrigeration compressors. To achieve this, compressors with different capacities are operated and recorded at different working speeds for different thermal conditions. Objective parameters are calculated
and tested using time domain signals and analyzed with spectral analysis methods. In addition to the objective parameters, subjective results are obtained through jury tests consisting of 75 people of different genders and age ranges. By considering objective parameters of sound quality as
input and sound quality evaluation values as output, a regression model is established. It is found that Loudness, Sharpness, and Degree of Modulation play an important role in compressor sound quality evaluations consider.
Noise reduction and visual disturbance performances of horizontal facade profiles for a multi-story high-rise apartment building
Authors: PARK Dong-Chae , KIM Yong-Hee , RYU Jong-Kwan
Published: October 2024

This paper simulates the noise reduction performance of horizontal profiles installed on the façade to reduce the external noise in high-rise residential buildings. The simulation used commercial software based on the ray tracing method and evaluated the performance by modeling
a representative rectangular-shaped 30-story apartment building in South Korea. The simulation assumed a four-lane road traffic noise source parallel to the front of the apartment. The key simulation values were cited from configurations derived in previous studies. The sound absorption points
were set at the center of each living room on every floor, and windows facing the road were considered for ventilation, being set to be partially open. Horizontal profiles for noise reduction were placed on the exterior of the building, starting from the 20th floor, with protrusion height
and vertical spacing as variables. These profiles were combined with noise barriers to assess their impact. As a result, it was confirmed that the noise barrier only reduced the noise in the lower floors, while the horizontal profiles on the upper part of the building could also reduce noise
in the upper floors. Additionally, the paper discusses the visual disturbance of the horizontal facade profiles visible from the living rooms.
Acoustic characterization of a bi-directional turbine
Authors: POIGNAND Gaelle , OLIVIER Come , PENELET Guillaume
Published: October 2024

A thermoacoustic engine converts thermal energy into acoustic energy, which can then be converted into electricity using an alternator. The conversion of acoustic-to-electric energy in thermoacoustic electricity generators usually relies on electromagnetic transducers. A bi-directional
turbine coupled to a DC motor offers a plausible alternative due to its simplified mechanical design, cost-effectiveness, and relatively good performance. Efficient coupling of a bi-directional turbine with a thermoacoustic engine requires a comprehensive understanding of its operating behavior.
This study aims to extend existing research by carrying out experimental characterization of a bi-directional turbine. This will involve measuring its transfer matrix and impedance under various acoustic conditions. The experimental results are then analyzed and compared with the predictions
of an electro-acoustic model.
Passive damping of several resonances using multi-branch resonant piezoelectric shunts
Authors: FLAMENT Pierre , LOSSOUARN Boris , RAMOND Éric , AUDRAIN Pascal , DEÜ Jean-François
Published: October 2024

Vibration damping using resonant piezoelectric shunts is a method to reduce the amplitude of mechanical resonances by coupling an electrical circuit to a structure through a piezoelectric transducer. The shunt consists of an inductor which creates a resonator tuned to the frequency
of the mode to be controlled. In order to damp several resonances simultaneously, multi-branch shunts can be used. Multiple electrical lines are then connected to a single piezoelectric patch. In this work, focused on purely passive control, a circuit involving resistors in series with the
inductors is considered. Indeed, each wire wound inductor is usually associated with a non-negligible series resistance due to copper losses. Several multi-branch shunt architectures have been proposed in the literature. From a selection based on their feasibility in passive control, two solutions
are retained: the Hollkamp shunt and the current blocking shunt. After numerical implementation, the two architectures are compared, notably by evaluating the effect of the inductance variations with respect to their nominal values and highlighting the influence of additional resistors.
Bi-orthogonality relations: general formulation, conversion to the FE format, and application for analysis of homogeneous and periodic waveguides
Authors: SOROKIN Sergey , BROBERG Peter , HANSEN Kristian , JOHANSEN Alexander , KRAUGH Oliver , LEDET Lasse
Published: October 2024

Bi-orthogonality relations are a powerful tool to solve complicated wave propagation problems in a surprisingly simple way. For any symmetric waveguide, these relations identify so-called Class A and Class B boundary conditions, for which eigenfrequencies and eigenmodes of a slice of
waveguide provide dispersion diagrams of propagating waves and (for periodic wave-guides) location of pass- and stop-bands. It is a straightforward matter to convert these 'class-consistent' boundary conditions to the FE format and use standard FE modal analysis software to study properties
of waveguides of arbitrary complexity. However, an application of this methodology, especially for periodic waveguides, is challenged by the necessity to track mode shapes and pair Class A and B eigenfrequencies into their modal families. A novel algorithm to resolve this issue is proposed
and tested on post-processing results of modal analysis in the AN-SYS environment. Underlying theory of bi-orthogonality, analytical solutions of benchmark problems, and FE case-studies are presented and explained.
Optimizing a small room for critical listening with Treble
Authors: PUZALOWSKI Philip , PEDERSEN Jesper , JEONG Cheol-Ho
Published: October 2024

This work presents a detailed validation of new software Treble launched in 2023 that hybridizes the discontinuous Galerkin method and pressure-based geometrical acoustics methods. We investigated a small studio for voice productions both through physical measurements and treble's room
acoustic simulations. By employing a dense measurement grid with a spacing of 25 cm at the ear level, a comprehensive validation of the room acoustic simulation was conducted in terms of room impulse responses, transfer functions, ISO 3382 acoustic parameters and sound pressure level distribution.
Treble's simulation successfully predict the room modes, ISO 3382 acoustic parameters as well as the sound level distribution. The study demonstrates the impact of speaker positions, particularly regarding their interaction with boundary surfaces and how this can be planned with the simulation.
Factors influencing noise annoyance across various transportation modes: lessons from the citizen science project "De Oorzaak"
Authors: BARROS Ablenya , DECORTE Paulien , LEMBRECHTS Jonas , COUSCHEIR Karolien , JACQUEMIN Laure , VAN LAENEN Limke , OP DE BEECK Sara , DIELTJENS Marijke , DENS Nathalie , VAN HAL Guido , CASAS RUIZ Lidia , SPACOVA Irina , IVEN Verena , VERBRAECKEN Johan , VUYE Cedric
Published: October 2024

The citizen science initiative "De Oorzaak" invited adult residents of Flanders (Belgium) to fill out the "Large Sound Survey", gathering over 8,000 answers in a month. This comprehensive 51-question survey evaluated annoyance levels across various transportation
modes, drawing on established questionnaires like the Epworth Sleepiness Scale, Weinstein Noise Sensitivity Scale and Written Environmental Survey (SLO), organized by the Flemish government. It also aided in selecting participants for subsequent project phases. Comparing LSS results to the
latest SLO report revealed a significant self-selection bias, with 33.3% highly annoyed by noise compared to 11.6% from the SLO. A profile could be drawn for the most annoyed participants: noise-sensitive individuals living in apartments or studios, adults (26-61 years old), and residing in
densely populated areas. Regarding transportation noise, passenger cars and trucks lead as the most annoying sources, with %HA of 24.5% and 23.5%, respectively, followed by motorcycles and alike (%HA =21.5%). Conversely, rail and air traffic annoyance are considerably lower. Correlations were
drawn between the several noise annoyance sources and individuals' characteristics. Overall, population density, age, fatigue level and quality of life are the personal aspects that correlate more consistently with road, rail, and air traffic noise annoyance.