bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic radiation of a fluid-saturated microperforated plate
Authors: GALLERAND Lucie , LEGRAND Mathias , DUPONT Thomas , PANNETON Raymond , LECLAIRE Philippe
Published: October 2024

It is known that fluid-saturated microperforated plates (MPP) dissipate energy and are substantially damped through thermoviscous dissipation taking place in the thermoviscous skin on the solid wall of the perforations. The aim of this work is to explore the acoustic radiation of a
microperforated periodic cell to investigate the intercellular coupling and the complexity of near-field radiation, and to derive a criterion related to the near-field far-field transition. A numerical modeling using the finite element method is developed to solve the elastic and thermo-visco-acoustic
(TVA) multiphysics problem. The TVA calculates explicitly the thermoviscous losses on the acoustic wave in the periodic cell studied. Numerical results show that the distance of the near-far field transition is significant at low frequencies, passing through a minimum for a frequency depending
on perforation parameters (diameter and ratio) before increasing again as a frequency function. The radiated acoustic power and radiation efficiency are compared with those derived from the theoretical MPP vibration model. It is found that the microperforations and resulting added damping,
around a characteristic frequency, reduce the acoustic radiation efficiency of the MPP compared to the corresponding non-perforated plate.
Study on subway resilient wheel's influence on noise inside the vehicle and in the bogie area through the in-situ measurements
Authors: ZHOU Xin , ZHONG Shuoqiao , XIE Xinchang , SHENG Xiaozhen
Published: October 2024

Based on a new type of resilient wheel installed on a subway train, a measurement campaign is devised to evaluate the effectiveness of the resilient wheel in reducing noise. For reference, the same series of tests are carried out on another train of the same type but fitted with conventional
wheels. The measurements involve the noise of various parts of the vehicle-track system which are used to investigate the sources of wheel-rail rolling noise, the noise inside the vehicle, and the noise close to the wheels. The series of tests are conducted on the normal-conditioned and corrugated
track on which the two sets of trains pass through at difference speeds. It is found that the decrease of interior noise measured on the corrugated track is within the range of 0.2~10.5 dB(A), which is greater than on normal conditioned track after using the resilient wheels. This attributes
to the frequency range available for vibration reduction by using the resilient wheel covers the dominant frequency range of the excitation from corrugation.
Relation between occupation density and ambient noise in open plan offices: a study based on field measurements
Authors: LENNE Lucas , BROCOLINI Laurent
Published: October 2024

Although progress has been made over the last decade on the issue of well-being in open-plan offices, recent surveys show that employees are still dissatisfied with their working environment, particularly the noise environment, remains. However, standards exist to help ensure that open-plan
offices are designed to provide the best possible working environment. But, because of the scope of these standards, their recommendations can be contradictory. For example, the French ergonomics standard NF X35-102 makes recommendations on the sizing of workstations, likely to lead to office
occupancy densities that are incompatible with the ambient noise level objectives defined in the ISO 22955 standard. To resolve these contradictions, a field measurement protocol was implemented. It consists in (1) a real-time count of the number of people in the office, (2) a measurement
of ambient noise, (3) a questionnaire assessing employees' perception of their physical working environment. The data collected in several French companies will make it possible to establish relationships between the ambient noise level, the occupancy density and the perception of noise levels.
This paper presents an occupancy sensor developed for this study and measurements of ambient noise level and occupancy ratio during a working day in an open-plan office.
Concept of Electromagnetic inerter-based vibration absorbers
Authors: MESNY Louis , PEYROUSE Floriane , PAIXAO Jesse , CHESNE Simon
Published: October 2024

Inerter is a device that generates a force proportional to the relative acceleration between its two terminals. It has recently been shown that this unusual property can offer interesting advancements and performance in the realm of vibration isolation or dynamic absorbers. However,
the main developments have encountered difficulties in mechanical implementation (utilizing rotating discs and gears) or achieving high-frequency efficiency. The present study proposes to synthesize actively the dynamical behavior of an inerter in order to overcome these constraints. To address
the stability issue, collocated voice coils are employed as sensors and actuators at the interface of the moving masses of the device. In a case study of a hybrid tuned vibration absorber, a first experimental demonstration illustrates the feasibility of such a concept.
How to deal with unsuspected source of annoyance in electric vehicle cabin using the "sonic augmented" concept?
Authors: DUROYON Matthieu , SUSINI Patrick , MISDARIIS Nicolas , DAUCHEZ Nicolas , PARDO Louis-Ferdinand
Published: October 2024

The disappearance of the main source of noise with electric vehicles resulted in a breakthrough in car cabin sound experience. Despite significantly lowering the sound level pressure, one cannot claim perfect quietness is achieved. Indeed, as the auditory masking produced by the internal
combustion engine is not effective anymore, unsuspected sounds such as electric whistling, whining or switching are now part of this sound environment and may be identified as unpleasant sounds. However, drivers' expectations are to have audible feedback indicative of vehicle operation that
matches their expectations. Therefore, the presence of unwanted and unpleasant sounds, on the one hand, and the absence of desired and informative sounds, on the other hand, is an opportunity for sound design to create a new sound environment inside car cabins. The present work proposes a
"sonic augmented" concept based on the idea of adding designed sounds, called "masks", participating both in the overall soundscape augmentation and in the attenuation of unpleasant sounds, called "defects". Sound design strategies with different parametrizations
will be presented, as well as the results of two perceptive experiments whit the aims at evaluating the impact on perceptive attenuation of "defects" and the overall sound quality.
Advancements in railway noise simulation: assessment of tools for virtual validation
Authors: EUGUI Iñigo , CAMINAL BARDERI Rita , SAPENA Joan , GUIRAL Ainara
Published: October 2024

In pursuit of more efficient and cost-effective measurement campaigns, the railway industry is embracing the prospect of virtual validation based on simulations. The primary obstacle lies in the need for noise simulation tools capable of accurately replicating complex sources, installation
effects, noise propagation, ground reflection and, for some cases, the diffraction in the different train surfaces. This paper presents insights derived from European project Shift2Rail S2R-CFM-CCA-01-2019 Energy and Noise & Vibration WP6, concentrating on the validation and enhancement
of two exterior noise simulation tools, tailored for railway applications. The paper covers four reference cases, simulating exterior noise at standstill with diverse noise sources and varying source locations and noise emission (i.e. electrical noise, cooling, etc.). A correlation with previously
conducted measurements at typical receiver locations (7.5 meters from the track centerline) is carried out. The measurements were conducted in a "controlled" configuration, isolating as much as possible the analyzed noise source and gathering all the needed information about the
ground and train geometry. The evaluation between measurements and simulations is done against a global and a 1/3rd octave band criteria with successful results. Finally, key features essential for achieving more accurate simulations are listed.
Reshaping workspace soundscapes: An in-depth analysis of ISO 22955 compliance and its influence on acoustic comfort and wellbeing - a case study
Authors: VAN DORT Pascal , WENMAEKERS Remy , PASSLACK Lynn
Published: October 2024

The prevalence of hybrid office landscapes is on the rise, eliciting concerns among users primarily due to noise and the challenge of balancing two conflicting acoustic activities: oral communication and concentrated individual work. This study investigates the interplay between acoustic
comfort and wellbeing in an office setting, utilizing evidence-based data gathered through occupant surveys before and after a comprehensive renovation. Prior to the renovation, room acoustic calculations were performed to assess compliance with the acoustic parameters from the ISO 22955:2021:
"Acoustic quality of open office spaces". The office was transformed, guided by a human-centric approach, from a predominantly enclosed layout into one that incorporates a blend of open-plan areas and closed rooms designed for meetings, concentrated work and phone calls. Room acoustic
measurements were taken before and after the renovation that confirm compliance with ISO 22955. The results of the questionnaire indicate improvements in concentration, decision-making and contemplation, which corresponds well with acoustic parameter values achieved. Nevertheless, "disturbance
of nearby conversations" was not reduced as expected. The research delves into the connection between the indoor acoustic environment and subjective experiences of health, well-being, and responses to noise disturbances, emphasizing the need for tailored acoustic design to optimize overall
workplace experiences.
Study of the acoustic attenuation of 2D axisymmetric models of the human ear equipped with hearing protection
Authors: PENPEN KOMGUE LUCRECE BARBARA , ADIL FAIZ , SAFAA ASSIF , CHOUAIB ENNAWAOUI , DUCOURNEAU Joël , HAJJAJI ABDELOWAHED
Published: October 2024

The ear is the organ responsible for auditory perception. Its role is to amplify, transmit, and convert an acoustic wave present in the environment into an electrical pulse that the brain can interpret via the auditory nerve. The objective of this study was to develop two axisymmetric
2D finite element models of the human ear to predict insertion loss when a porous earplug is introduced into the ear canal. In these models, the structure-acoustic interaction was resolved by finite element analysis. For a better representation, assumptions and boundary conditions (such as
fixe boundary condition, spring-mass-damping boundary condition, etc...) are considered. The tympanic ring and the earplug are assumed to be fixed, and a load of what comes after the posterior part of the tympanic ring (the ossicular chain) has been replaced by an equivalent mechanical impedance
mass-spring-damper system. The first model has a regular geometry, and the second model is obtained by reconstructing a 3D model. These two models were inspired by our previous work. For each model, the insertion loss (IL) is predicted and the results obtained are compared with those of the
sound attenuation measurements of hearing protection performed in the laboratory.
Underwater sound produced by operational floating wind turbines
Authors: MARMO Brett , RISCH Denise , VAN GEEL Nienke , FAVILL Guy
Published: October 2024

Deployment of offshore wind turbines is growing rapidly. Conventional "fixed bottom" wind turbines are limited to water depths of ~60 m, so deployment of offshore turbines to greater water depths requires floating systems. Both fixed bottom and floating turbines produce operational
noise that impacts the marine environment. While the operational noises from fixed bottom turbines are relatively well understood, floating turbines are comparatively novel technologies and there is uncertainty as to the noise they will produce and its impact on the marine environment. Results
from acoustic surveys of two floating wind farms off the Scottish Coast are presented; Kincardine wind farm which uses semi-submersible floating systems; and Hywind which uses a floating spar structure. The acoustic signature of each consists of continuous tonal noise related to drivetrain
vibration and transient broadband events related to the mooring systems. A machine learning algorithm was used to discriminate between drivetrain noise and mooring noise. Sound propagation modelling was used to determine the source levels for turbines at each wind farm allowing a comparison
of the noise signature of different floating structures.
Prediction of the acoustic particle velocity in aerodynamic flows and its applications to the boundary element method
Authors: HE Jiahua , ZHANG Zhicheng , LIU Qiuhong , ZHOU Peng
Published: October 2024

The acoustic variables are essential for understanding sound energy transmission and redistribution. The previous methods focused on acoustic pressure without the acoustic particle velocity, which is not enough for acoustic field evaluation. In this paper, an analytical formula for
acoustic particle velocity prediction is developed based on the permeable surface integral solution of a vector wave equation. The validation examples are presented with stationary dipole and rotational monopole. The acoustic quantities, pressure, and velocity are solved at the same time and
will be applied as input for the boundary element method (BEM) to evaluate the sound scattering problem in the frequency domain. Furthermore, the method is applied to study the acoustic field of flow passing a cylinder. The acoustic pressure shows good agreement with the flow observer. The
acoustic particle velocity is also investigated.
Numerical modeling of acoustic visco-vhermal losses: simplified implementations and their limitations
Authors: CUTANDA HENRIQUEZ Vicente
Published: October 2024

Several numerical adaptations have been proposed to account for viscous and thermal losses of acoustic waves. This is a physical effect that is mostly relevant in a region very close to boundaries, the so-called boundary layers, in the micrometer range. It is therefore relevant when
modeling small devices such as acoustic transducers and acoustic metamaterials. An often used modeling technique collapses the viscous and thermal losses into a boundary layer impedance (BLI), which is used in a calculation where the regular wave equation with no losses is discretized. However,
this method has two shortcomings: i) the boundary layers may not overlap, and ii) it assumes flat surfaces. The BLI can be used either with the Finite Element Method (FEM) or the Boundary Element Method (BEM). BEM and FEM implementations with visco-thermal losses having no such restrictions
also exist, at the cost of a heavier computational burden. This contribution discusses the shortcomings and advantages of the simulations using BLI as compared with full implementations and points to possible ways to overcome them. The BEM is employed to illustrate the analysis.
Advancing noise reduction strategies for domestic air-source heat pumps
Authors: SINGH Jujhaar , KENNEDY John
Published: October 2024

With the increasing adoption of heat pump technology in the energy sector, addressing noise emissions is crucial for public acceptance, regulatory compliance, and sustainable urban planning. Air-Source Heat Pump's noise emission, noise sources, reduction strategies, problematic frequency
ranges, and noise transmission within buildings are considered. Various noise reduction strategies, including the strategic siting, enclosures, and vibration isolation techniques, are discussed. This study considered a scenario of heat pump noise emission which generated noise complaints.
The heat pump noise source is investigated though 24 hour monitoring of far field acoustics in a suburban residence. A commercial implementation of ISO 9613 is used to predict the environmental noise impact. Results demonstrated that levels exceeded natural background by as much as 10-15 dB
but that this could be mitigated through strategic placement of the heat pump. This study underscores the importance of implementing comprehensive noise control strategies for Air-Source Heat Pumps in urban areas to safeguard community well-being and ensure regulatory compliance. By integrating
innovative noise reduction technologies and considering factors such as strategic location of Air-Source Heat Pump, installation practices, building design, and proper urban planning policies can enhance Air-Source Heat Pump's reliability while promoting a sustainable urban development.
Internal gravity waves in the middle atmosphere and their impact on infrasound propagation across the International Monitoring System
Authors: LISTOWSKI Constantino , STEPHAN Claudia Christine , KRISTOFFERSEN Samuel , LE PICHON Alexis , HAUCHECORNE Alain , ACHATZ Ulrich , VöLKER Georg Sebastian , KIM Young-Ha , BöLöNI Gergely , VERGOZ Julien
Published: October 2024

Infrasound technology is used to monitor atmospheric events in order to guarantee compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Over the 60 infrasound stations initially planned, 53 are operational to date as part of the International Monitoring System (IMS). As
opposed to the waveform-related technologies that are used by the IMS to monitor the two other media of the geosphere (the underground and the oceans), infrasound waves are travelling in a continuously varying propagation medium. From minutes to hours and from a few hundreds of meters in the
vertical to thousands of kilometers in the horizontal, atmospheric perturbations affect detection capabilities of the IMS at various scales. These perturbations need to be taken into account, for infrasound analysis to be able to provide accurate localization and characterization of sources
of interest. In particular, internal gravity waves (atmospheric buoyancy waves) pose a serious challenge to atmospheric modelling because of the unresolved involved processes. They can dramatically affect transmission losses across the globe. Through numerical experiments and using high resolution
modelling outputs of the atmosphere, backed up by atmospheric measurements, we demonstrate how gravity waves impact infrasound attenuation and drive signal amplification across the IMS.
Innovative approaches to promote inclusive processes for noise barriers landscape integration
Authors: ANTONIAS Nicoletta , MONTESI Marco , GIANGRANDE Cinzia , BARBAGLIA Paola Eugenia , FANTOZZI Marco
Published: October 2024

Noise barriers, in addition to their own functions as specific mitigation interventions to protect health, can represent important architectural elements, both in urban environment and natural context. In this perspective the design stage cannot ignore an integrated evaluation of the
reference social and natural context based on the peculiarities and vocations of the territories involved. Aiming to the primary objective of identifying the "right" project that best fits into the reference territorial context, also for acoustic barriers it is therefore necessary
to carry out a preliminary analysis of the socio-territorial and landscape context to understand specific local features of the territories and promote barriers as an essential part of the urban environment and landscape in a synergistic vision between innovation and sustainability also through
new models of co-design and co-management with the communities involved. This paper aims to describe the approach adopted by RFI - the National Manager of the Italian Railway Network - to promote effective integration and synergy between noise mitigation interventions and the territorial reference
context with the aim of creating a "tailor-made" project with the contribution of citizens and stakeholders.
Exploring sound diffusion in learning environments through experimental and wave-based analysis
Authors: FRATONI Giulia , D'ORAZIO Dario
Published: October 2024

Acoustic design guidelines in learning environments generally involve specific requirements of reverberation time (T20), speech clarity (C50), and speech transmission index (STI) to ensure adequate quality for spoken communication. Predictive formulas recommended by international standards
rely on ideal diffuse field theory as a crucial factor for meeting adequate room acoustics criteria. However, such theoretical assumptions are barely encountered in real-world rooms, undermining the predictions' accuracy. The present work explores the main factors influencing sound diffusion
in classrooms by means of in-field acoustic measurements and numerical models. In detail, different desk configurations and the installation of materials with varying acoustic impedances at the suspended ceiling have been studied to evaluate the associated increase in sound diffusion. Among
the several metrics to quantify sound diffusion, the standard deviation of measured reverberation time values has been selected in the present study. Experimental and simulated data findings reveal that the furniture layout with a single desk arrangement and the suspended ceiling's treatment
with porous and perforated ceiling tiles increase sound diffusion by exploiting edge diffraction and material discontinuities, respectively.
Numerical modeling of acoustic scattering characteristic with wavenumber domain admittance
Authors: HOSHIKA Satoshi , IWAMI Takahiro , OMOTO Akira
Published: October 2024

A conversion from the wavenumber domain acoustic reflection coefficient to the wavenumber domain acoustic admittance is formulated to deal with the acoustic reflection properties of arbitrary materials in numerical simulation. This method, which can represent arbitrary reflection directional
properties, is an extended reactive boundary condition modelling method based on a spatial Fourier transform over the boundary surface. The advantages are that it is computationally inexpensive because it does not need to consider the interior of the material in the analysis, and that it can
handle reflection characteristics obtained from actual measurements, etc. From the results of applying the wavenumber domain acoustic admittance to the numerical analysis, it has been confirmed that the proposed method can handle not only the specular reflection component, but also when arbitrary
scattering components are included, or when the main reflection direction is changed from the specular reflection direction.
Virtual assessment of phone booths' acoustic performance in laboratory and office environments
Authors: FRATONI Giulia , DE SALVIO Domenico , D'ORAZIO Dario
Published: October 2024

The irrelevant speech noise is one of the significant issues affecting workers' productivity and comfort. Acoustic furniture is the most common solution addressing this problem: mobile phone booths and partially closed workstations are two examples. The acoustic performance of such
devices is defined with laboratory tests according to ISO 23351-1:2020. The sound power level measured in reverberation rooms with and without the product determines the reduction of speech A-weighted sound power level (DS,A). However, predicting acoustic performance in real-world scenarios
is still challenging. The present work explores the discrepancies between DS,A, and apparent speech reduction (D'S,A) through numerical models. The study assesses the performance difference between a calibrated virtual reverberation room and virtual open-plan offices maintaining the same acoustic
properties, i.e., sound transmission and sound absorption, of a typical two-person phone booth. Moreover, the study investigates the fluctuation on D'S,A changing main room acoustic criteria, e.g., the reverberation time (T) and the total absorption area (A). Results help define ray-based
simulations' reliability in predicting furniture ensembles' acoustic performance.
Two-dimensional visualisation of a travelling sound wave over porous medium
Authors: YUREK Arif , ÖYRY Aleksi , LOKKI Tapio
Published: October 2024

Prior research has demonstrated a variation in sound speed and a wave bending in the air when an acoustic wavefront approaches a porous medium at a grazing angle. The impact is found to be explicitly dependent on the frequency of the sound and the nature of the adjacent absorber. The
current study expands the investigations by using a distributed array of eight microphones mounted on a single-axis motorised mover. The measurement setup allowed for an extensive collection of impulse responses within a confined area near a horizontally placed porous panel. The sensors captured
a frequency sweep every 10 millimetres on multiple horizontal planes above the air-material boundary. Moreover, the array configuration allowed for simultaneous capture of wave propagation both above and outside the projection area of the absorbing material. The progression of a travelling
wavefront is reconstructed as an image-sequence-based 2D animation on four discrete vertical planes, 60 cm by 50 cm each, traversing or passing outside the porous material.
Influence of the sound propagation models to predict far field wind turbine noise
Authors: GLOAGUEN Jean-Rémy , FINEZ Arthur , LE BOURDAT Colin
Published: October 2024

During the development process of a wind farm, the noise impact on neighboring residents is of crucial importance to limit annoyance and comply with local regulations. In France, this assessment is carried out by modelling the propagation of sound from each wind turbine to residents.
For wind farm owners, this phase will in fine define the operation of the wind farm and therefore its electricity production. However, there are major concerns and uncertainties during this modelling phase. A concrete example of the influence of the choice of propagation model on the production
of a wind farm is presented, giving an idea of its economic impact. Comparisons of the impact of wind farm noise modelled by engineering models with measurements taken on wind farms in operation provide a better understanding of the choice of certain methods or parameters. Taken together,
these observations suggest areas for further research and development, with the aim of perhaps defining a more restricted framework for the sound propagation modelling stage, in order to help operators predict wind farm noise more accurately.
Low noise pavement characterization through TCN analysis
Authors: KANKA Simon , MONTICELLI Alessandro , MORO Antonino , FIDECARO Francesco , LICITRA Gaetano
Published: October 2024

The use of low-noise pavements is a valid solution to reduce road traffic noise at source. Further studies are needed to optimize their design and ensure their durability. In this work, low-noise pavements were characterised using innovative and traditional methods on four different
pavements: two of them contained crumb rubber added by dry and wet processes, one had an optimized texture and the last one was a traditional dense asphalt concrete. Using a sensor inside the tyre, the tyre cavity noise (TCN) was recorded and analysed, putting it in relation with the Close
Proximity Method (CPX) data and the pavement texture measured by a laser profilometer. This paper aims to improve the knowledge of the relationship between the vibrational components of the tyre-pavement interaction using new and old descriptors, extending the types of pavements studied in
past researches.
Noise monitoring of loud vehicles in four Dutch cities
Authors: DITTRICH Michael , WESSELS Peter
Published: October 2024

Excessive noise from loud cars, motorcycles, mopeds, trikes and quads is commonplace in Dutch cities and is a major source of annoyance. In order to assess the sources, causes and potential solutions, TNO has performed a series of noise monitoring campaigns in four major cities including
vehicle identification. Sound and vehicle data was acquired at 3 locations in each city for a period of five days. Several steps were applied to separate vehicle noise from other noises, and to attribute the noise to the correct vehicles. The resulting analysis provided insight into the types
of vehicles and driving conditions causing most noise. A set of characteristic driving conditions were derived from the measurement data, including high acceleration, engine revving, engine backfire, high engine speed and others. Besides driving behaviour, vehicle modifications such as louder
exhausts, removed dB-killers and mechanical or electronic engine modifications are common causes of high noise levels. Also an overview of suggested mitigation options and future outlook is given, based on the findings of the analysis.
The Eindhoven Acoustic Virtual Reality (EAVR) toolkit in education and beyond
Authors: WILLEMSEN Silvin , HORNIKX Maarten
Published: October 2024

The Eindhoven Acoustic Virtual Reality (EAVR) toolkit is an open-source software intended to teach undergraduate students in architecture principles in acoustics in an intuitive and interactive way. EAVR allows students to experience and interact with their 3D models in Virtual Reality
(VR), by changing the materials of the surfaces and changing the size of the room in real time. Since its conception in 2019, EAVR has been employed in several courses at the Eindhoven University of Technology (TU/e), where students (re)created various spaces, ranging from lecture halls to
concert venues. Using students' feedback, an improved version of the toolkit, named EAVR-v2, was created and is presented in this paper. Two spin-off projects of this, a restaurant environment and a concert hall, were presented at the annual Dutch Design Week (DDW) in Eindhoven, which provided
general insights in the usability of the toolkit. This paper presents several findings made while using EAVR in education as well as during the DDW. The findings indicate that students enjoy working with EAVR, and highlighted aspects that need improvement.
Comparison of standard Bayesian methods and PINNs for the reconstruction of acoustic fields in 'in situ' combustion chambers
Authors: YAO Junting , SILVA Camilo Fernando
Published: October 2024

Acoustic measurements, utilizing sensors such as microphones strategically placed, are commonly employed to monitor acoustic systems and extract quantities of interest, such as acoustic reflection coefficients. Typically, a specialized test rig must be constructed to allow for external
harmonic acoustic forcing via loudspeakers. In this study, we propose two different methods: physics-informed neural networks (PINNs) and the extended Kalman filter, to reconstruct the acoustic field of a system and assess the acoustic reflection coefficient at a defined boundary. We demonstrate
numerically that a single external broadband forcing signal suffices for these methods. This implies that these methods can be applied to 'in situ' configurations, such as industrial combustion chambers, where the broadband nature of combustion noise serves as the acoustic forcing element.
Furthermore, we investigate the performance of the two aforementioned methods in reconstructing the acoustic systems and corresponding acoustic boundaries.
Literature review on perception and evaluation criteria of soundscapes among sighted and visually impaired individuals
Authors: DONG Jingying , KARMANN Caroline
Published: October 2024

The sound and its qualities are important of the quality of built environments. The concept of soundscape, rooted in user's subjective perception of context, plays a crucial role in peoples' overall assessment of their surroundings. This study attempts to discern the similarities and
differences in soundscape perception and evaluation between sighted and visually impaired users through a literature review. The results suggest that visually impaired people perceive soundscapes as having the additional role of helping to understand spatial boundaries and providing information
about the external environment. The soundscape assessment protocols were adapted both to take account of this feedback and to compensate for their inaccessibility (e.g., questionnaire format and potential hazards associated with soundscapes). The review output also suggested that visually
impaired people orient their impressions more towards their expectations. Particularly, the impact of event-based sounds, characterized by spatial and semantic features, extends to influencing their experiences and behaviors within a given space. Despite distinctions, there exist commonalities
in their perception of certain acoustic features between visually impaired and sighted individuals, such as sounds from nature having a positive effect on both groups and mechanic sound noted as negative. This review ends by listing research gaps and methodological opportunities.
Acoustic materials based on the Gosper curve
Authors: ZIELINSKI Tomasz G. , D'AGOSTINI Marco , GIORGIA Franchin , COLOMBO Paolo
Published: October 2024

In this work, slotted acoustic materials based on a space filling curve called the Peano-Gosper curve are proposed and investigated. The slits in such materials form a complex pattern because they are divided by walls built along lines generated by the Gosper curve algorithm. The pattern
can be twisted around an axis normal to its surface to increase the tortuosity inside the material, and therefore, modify its acoustic properties, which can be controlled by the turning angle or pitch of the twist. A highly efficient semi-analytical model has been developed to accurately predict
the acoustic properties, in particular the sound absorption of such materials. It only requires a representative part of the pattern, or better, scanning the surface of the fabricated material so that the actual geometry and dimensions (in particular slit widths) are well reproduced in a two-dimensional
finite element mesh generated on a representative fluid domain. The mesh is used to solve a dedicated Poisson problem and determine a few key parameters, and the rest of the modelling is based on analytical formulas. Material samples with straight and twisted slit patterns were 3D printed
and then measured in an impedance tube to confirm semi-analytical sound absorption predictions.
Quieter and calmer than before: sound level measurement and experience in the intensive care unit at Erasmus Medical Center
Authors: ÖZCAN Elif , SPAGNOL Simone , GOMMERS Diederik
Published: October 2024

Intensive care units (ICUs) are the ultimate socio-technological environments known for their loud sound levels. Alarms, noise produced by patient support devices, loud conversations, physical interactions with tools and the environment in general contribute collectively to a sound
quality generally perceived as low. This paper reports the results from a study conducted inside the old and new ICUs at Erasmus Medical Center, Rotterdam, the Netherlands. Sound level measurements have been collected continuously for three weeks in several matching rooms inside the old and
new ICUs at full operational level at a one-year distance from one another. The results support the idea that changes in architectural layout, procedures, and culture have contributed to a significant decrease of the measured sound levels across all daily shifts, both inside patient rooms
and in the nurse stations. We further discuss the results in light of a series of contextual considerations that emerged from interviews with healthcare providers (i.e., nurses and intensivists) who actively worked in both the old and the new ICU.
Study of speech intelligibility in anechoic and reverberant environments using Slovak language
Authors: HUDOKOVA Dominika , CHMELIK Vojtech , VAN WIERINGEN Astrid , RYCHTARIKOVA Monika
Published: October 2024

Binaural aspects play a significant role in speech intelligibility, with listeners demonstrating better performance in scenarios where the signal and noise sources are spatially separated, leveraging interaural time and level differences for improved sound segregation and localization.
Thus, the question is: How do binaural aspects influence speech intelligibility in different spatial configurations of signal and noise? In this paper, speech intelligibility is examined in an anechoic and reverberant environment, specifically focusing on three configurations of signal and
noise: (1) signal and noise both coming from the front at a distance of 1-meter, (2) signal from the front and noise from the right side (90 degrees) at a 1-meter distance, and (3) signal from the front and noise from the back (180 degrees) at a 1-meter distance. The study employs two different
noises-speech-weighted noise and multi-talker noise-during listening tests conducted in the Slovak language. Furthermore, the study compares the outcomes with a similar experiment conducted a few years ago in the Dutch language, providing valuable insights into language-specific variations
in speech perception under different acoustic environments.
The modeling of acoustic black hole beam by spectral element method
Authors: CARVALHO DOS SANTOS Jean Pietro , CAMPOS DOS SANTOS José Maria
Published: October 2024

A technique developed in recent decades for the passive control of vibrations and noise is the Acoustic Black Hole (ABH). The structural ABH effect is achieved by incorporating a local modification in the thickness of a thin structure, typically a beam or a plate, with a variation in
thickness according to a spatial power law. The combination of the variation in the thickness power law and a local increase in damping, provided by the concomitant application of layers of viscoelastic material, produces a significant reduction in the wave propagation speed and an increase
of attenuation properties. As an elastic wave propagates within an ABH, its propagation speed decreases smoothly and continuously, in theoretical case, when the structure's thickness disappears at the end of the ABH, the wave speed drops to zero. For practical applications, ABH is typically
combined with dissipative materials to obtain significantly higher structural loss factors. This work aims to establish a numerical approach for modeling and designing a beam-type structural one-dimensional ABH device for vibration control device using the Spectral Element Method (SEM) and
verified by the Finite Element Method (FEM). Examples are performed, and the results are compared with those found in the literature.
Methodology for determining new CNOSSOS-EU vehicle sound power coefficients using type approval data
Authors: SCHLIEPHAKE Carolin , USZYNSKI Olaf , WERNER Dominik , URBAN Peter
Published: October 2024

CNOSSOS-EU is a standardized framework for strategic noise mapping across the European Union which member states are required to conduct every five years. The framework provides an approach to assess noise from different sources, including road traffic noise. Road traffic noise is primarily
caused by vehicles. In CNOSSOS-EU, the vehicle exterior noise is modeled using fixed sound power coefficients. These coefficients were derived from measurements conducted up to 2006. Although significant progress has been made in reducing vehicle exterior noise, the existing model does not
account for this technical progress. This paper first reviews the evolution of exterior noise legislation and its impact on vehicle noise levels. It then presents a new procedure for integrating the technical progress into vehicle source modeling in CNOSSOS-EU by incorporating type approval
data. For demonstration purposes, this procedure is applied to up-to-date type approval data of M1 vehicles, resulting in a more accurate representation of current noise emissions. This research contributes to the refinement of the CNOSSOS-EU model, aligning it with the current state of technology
and providing a more precise basis for environmental noise assessment.
Aircraft noise effects in vulnerable populations
Authors: BARTELS Susanne , QUEHL Julia , FRITSCH Kyra , AESCHBACH Daniel
Published: October 2024

Vulnerable population groups (e.g. children, elderly people, shift workers) have not been the focus of investigations into the effects of transportation noise for a long time. In two field studies in the vicinity of Cologne/Bonn Airport, we therefore investigated the effects of nocturnal
aircraft noise on sleep as recorded with polysomnography and self-reported sleep quality as well as short-term annoyance in 51 primary school children (8-10 years) and 44 elderly people (55 - 76 years). In a laboratory study, the effects of aircraft noise on the same outcome variables were
compared between 17 participants who slept during the day (19 - 36 years) and 16 participants who slept at night (18 - 35 years). This article provides an overview of the results of these studies in vulnerable groups. Noise effects were more pronounced in participants who slept during the
day than in those who slept at night. The findings for children and older people were less consistent and showed effects of nocturnal aircraft noise either on sleep (children) or on self-reported sleep quality and annoyance only (elderly people). Results of the vulnerable groups are discussed
in comparison to findings in middle-aged adults.
Evaluating the measurement of the velocity level difference for building constructions which combine Type A and Type B elements
Authors: MAHN Jeffrey , SKODA Sabrina , B. CUNHA Iara , MüLLER-TRAPET Markus
Published: October 2024

As part of an ongoing research project in the new four-room flanking facility at the National Research Council Canada, the velocity level differences between cross-laminated timber floors/ceilings and lightweight timber framed walls have been measured according to the standard, ISO
10848-1. The apparent sound reduction indices between the pairs of rooms have also been measured according to ISO 10848-1. The measured apparent sound reduction indices are compared to those predicted according to the standard, ISO 12354-1 based on the measured velocity level differences,
the resonant transmission losses and the dimensions of the elements of the flanking paths between the room pairs.
Noise annoyance and application of the Harmonica index at short time intervals
Authors: MASULLO Massimiliano , TOMA Roxana Adina , YANG Ming , BRAMBILLA Giovanni , MAFFEI Luigi
Published: October 2024

The Harmonica index (HRM) is aimed to quantify the perceived noisiness of environmental sounds on an hourly basis by a score on a linear scale from quiet to very noisy. The index is computed as the sum of the background noise (BGN) and the sound events (EVT) emerging from BGN and has
been developed to facilitate communication with the public and to help local authorities in the decision-making process. In this paper, the HRM index has been applied to short time intervals, providing an increase in the time resolution of sound level acquisition from 1 s to 0.1 s. Six sound
recordings were considered, taken in different urban contexts (i.e., parks, road traffic noise, construction sites), each lasting two minutes and divided into four sequential soundtracks of 30 s each. The tracks were played back randomly in laboratory listening tests to collect ratings of
perceived annoyance given by participants after each soundtrack and, at the end of the four soundtrack sequences, the annoyance rating of the whole sound. The results show that the short-time application of the index is sensitive to the qualitative characteristics of the background and events,
and needs improving before being used.
Environmental sound classification on an embedded hardware platform
Authors: BIBBó Gabriel , SINGH Arshdeep , D. PLUMBLEY Mark
Published: October 2024

Convolutional neural networks (CNNs) have exhibited state-of-the-art performance in various audio classification tasks. However, their real-time deployment remains a challenge on resource constrained devices such as embedded systems. In this paper, we analyze how the performance of
large-scale pre-trained audio neural networks designed for audio pattern recognition changes when deployed on a hardware such as a Raspberry Pi. We empirically study the role of CPU temperature, microphone quality and audio signal volume on performance. Our experiments reveal that the continuous
CPU usage results in an increased temperature that can trigger an automated slowdown mechanism in the Raspberry Pi, impacting inference latency. The quality of a microphone, specifically with affordable devices such as the Google AIY Voice Kit, and audio signal volume, all affect the system
performance. In the course of our investigation, we encounter substantial complications linked to library compatibility and the unique processor architecture requirements of the Raspberry Pi, making the process less straightforward compared to conventional computers (PCs). Our observations,
while presenting challenges, pave the way for future researchers to develop more compact machine learning models, design heat-dissipative hardware, and select appropriate microphones when AI models are deployed for real-time applications on edge devices.
Case study of simplified reverberation time measurement under multiple conditions using a sound level meter
Authors: EZOE Taisuke , EZOE Taisuke , KAZAMA Ryosuke
Published: October 2024

Recent advancements in the computational capacity of sound level meters have facilitated the simultaneous recording of diverse calculation results and waveform recording data. Traditionally, reverberation time determination entailed manually adjusting a linear regression line to the
reverberation decay curve derived from recorded sound levels, followed by reverberation time computation based on the gradient of said line. However, automated techniques have made reverberation time calculation via a sound level meter feasible. This paper discusses a case study evaluating
the efficacy and considerations of simplified reverberation time measurements conducted across various conditions, encompassing scenarios with multiple sound sources and diverse indoor environments. The study leveraged recorded data from a sound level meter and employed automated methods simulated
on a personal computer.
Validation of an absorption coefficient measurement technique using two cardioid microphones in any impedance tube
Authors: HOSHI Kazuma , HANYU Toshiki
Published: October 2024

We have proposed a technique for measuring sound pressure and particle velocity using a combination of cardioid microphones and then applied it to obtain the acoustic absorption coefficient in a tube. So far, we have revealed that either using one cardioid microphone measured twice
or using a pair of cardioid microphones measured once are both suitable for the measurement and that the calibration of the cardioid microphones is required. If the technique works correctly, this technique holds promise for measuring the acoustic absorption coefficient of various specimens
in any tube and with any cardioid microphones. To validate the technique's effectiveness, we conducted experiments in multiple square-section wooden or round-section steel tubes, with specimens of glass wool and polyester terephthalate (PET) wool. As a result, this technique can provide accurate
absorption coefficient measurements in any tube configuration.
Vibration analysis of 3D printed cymbals and Tzouras top plates
Authors: BREZAS Spyros , KASELOURIS Evaggelos , GRIGORIOU Despoina , PAPADAKI Helen , ORPHANOS Yannis , BAKAREZOS Makis , PAPADOGIANNIS Nektarios Andrea , DIMITRIOU Vasilis
Published: October 2024

An integrated method of determining the vibration characteristics of musical instruments is here presented. The method includes modal measurements and holographic imaging, FEM modelling and simulations. Parts of musical instruments made of composite materials have been simulated, printed
and measured. The vibrational response of 3D printed cymbals and Tzouras top plates, a Greek traditional stringed musical instrument, is experimentally measured and computationally simulated. The PLA printed parts vary in geometry and thickness. The frequency response functions, and the vibrational
modes are presented and further studied in relation to the aforementioned geometry variations. The experimental findings provide inputs to FEM modeling and simulation parameters.