Archives of Acoustics
type: channel
description: Archives of Acoustics is an English-language peer-reviewed online quarterly journal publishing original research papers from all areas of acoustics and abstracts from some specialized acoustical conferences. It gives free internet access to its full content to current issues. Archives of Acoustics, the peer-reviewed online quarterly journal, publishes original research papers from areas of acoustics like: linear and nonlinear acoustics: theory, acoustical measurements, and instrumentation acoustics of music: music theory, signal processing, and instrument building physiological acoustics: hearing, audiology, and psychoacoustics speech processing and communication systems: speech production and perception, voice recognition and control architectural, building, and environmental acoustics and soundscape computational and numerical acoustics sound and ultrasound in biology and medicine: ultrasonic imaging, ultrasonography, high-intensity ultrasound, therapeutic ultrasound electroacoustics: research in the field of microphones, loudspeakers, headphones, accelerometers, acoustic calibrators noise, noise control, and vibration: theory and instrumentation for noise determination and sound quality criteria, audio signal processing and transducers, acoustic materials sonochemistry: acoustic cavitation, sonoprocessing, and all aspects of physical and chemical effects of sound ultrasound and ultrasonic transducers underwater acoustics: acoustical oceanography and fisheries acoustics acousto-optics artificial intelligence in acoustic research This journal provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. All articles are published on Creative Commons licence CC BY 4.0. Archives of Acoustics is available in Diamond Open Access and no fees are charged to the authors or readers. Journal Metrics MNiSW (2024): 100 | Impact Factor 2024: 0.9 (2023: 0.6) | CiteScore 2024: 1…
publisher: Institute of Fundamental Technological Research (IPPT) of the Polish Academy of Sciences
language: en
publication name: Archives of Acoustics
issn: 0137-5075
copyright: Copyright on any open access article in the Archives of Acoustics published by the Polish Academy of Sciences and the Institute of Fundamental Technological Research Polish Academy of Sciences is retained by the author(s). The authors grant the Polish Academy of Sciences and the Institute of Fundamental Technological Research Polish Academy of Sciences a license to publish the article and identify themselves as the original publisher. The authors also grant any user the right to use the article freely as long as its integrity is maintained and its original authors, citation details, and publisher are identified. The Creative Commons Attribution 4.0 International CC BY 4.0 formalizes these and other terms and conditions of publishing articles. Exceptions to copyright policy For the articles that were published between 2019– 2023 (including No. 1 and 2, 2023), the policies are as follows: The Creative Commons Attribution License-ShareAlike 4.0 formalizes these and other terms and conditions of publishing articles: https://creativecommons.org/licenses/by-sa/4.0/. For the articles which were previously published, before year 2019, policies that are different from the above. In all such, access to these articles is free from fees or any other access restrictions. Permissions for the use of the texts published in that journal may be sought directly from the Editorial Office of Archives of Acoustics
items: The mechanism of formation of the cutoff frequency in an acousto-optic delay line and some proposals for its measurement
items: A Study of Damage Modes Recognition of Polypropylene Fiber Reinforced Recycled Aggregate Concrete Based on Principal Components of Acoustic Emission Signals
items: Modeling of High-Speed Ultrasonic Testing of Railway Rails in Track Inspection
items: Indian Sign Language Alphabet Recognition and Speech Synthesis Using a Hybrid Deep Learning Approach
items: Construction Method of Sparse Dictionary for Multi-order FRFT Domain Feature Fusion
items: Causality- and Passivity-Constrained Nonnegative Attention for Interpretable Structure-Borne Road-Noise Prediction in Battery Electric Vehicles
items: Dispersion Characteristics of SH waves in a Rotating Micro-structured Plate with Restrained Boundaries
items: Flanking Sound Transmission in Massive-Lightweight Connections
items: Study on Dual-Stage Amplification Cascaded Piezoelectric Transducer for High-Power Applications
items: In Memoriam Professor Eugeniusz Kozaczka
items: Impact of Perforated Sheet Geometry on the Insertion Loss of Absorption Silencers
items: Analysis on Modal Distribution and Modal Density-Based Crossover Frequency in Cabin-Sized Enclosures
items: TimeGAN and Coordinated Attention Prototype Network Based Prediction Model for Infrasound Signal
items: An Empirical Approach to Investigate Environmental Effects on Acoustic Signal Speed in Oceanic Layers
items: Ultrasonic Estimation of Pressure Dependent Non-Linearity Index in Liver
items: Few-Shot Transfer for Speech Enhancement Using SEGAN with Stability Guardrails
items: Application of Acoustic Metamaterials in the Design of Muffling Unit of Internal Combustion Engine
items: Subwavelength Underwater Imaging of a Wire Array Metamaterial Based on Fabry–Perot Resonance
items: Similarity Analysis and Target Strength Correction of Non-Proportional Scaled Models Based on Highlight Model Theory
items: Application of ISO 12913 Standard to Assess Urban Soundscapes: A Case Study on Poznań
items: Single-Sensor Passive Ranging of Underwater Monopoles Using Near-Field/Far-Field Energy Contrasts
items: Analysis of Decision Fusion in Speech Detection
items: Active Vibration Suppression of a Thin Circular Pipe
items: The influence the surface of ventilation duct on sound attenuation in the airflow
items: The Impact of Generated and Expressive Modulation of the Synthetic Instrument Sound Parameters on the Impression of Naturalness
items: Potential Applications of Ultrasonic Parametric Array Loudspeakers (PALs) in Room Acoustic Measurements
items: Cube-Shaped Sound-Insulating Enclosures: Experimental Tests and Calculation Models
items: Laboratory Evaluation of Underwater Acoustic Attenuation Provided by Air Bubble Curtains
items: Simulation Analysis of Beam Intensity Attenuation Patterns and Source Depth Estimation Using a Vertical Long Line Array
items: Comparison of Methods for Determining the Airflow Resistivity of Porous and Covering Materials

The mechanism of formation of the cutoff frequency in an acousto-optic delay line and some proposals for its measurement
type: item
description: The structure of the acousto-optic delay line and possible areas of its application are discussed. The necessity of determining the cutoff frequency of the acousto-optic delay line in all areas of its application is substantiated. The relationship between the cutoff frequency of an electric circuit and its time constant is discussed. The obtained result is extrapolated to the acousto-optic delay line, in which the cutoff frequency is formed by a completely different mechanism. The mechanism of cutoff frequency formation in the acousto-optic delay line is discussed. It is shown that the cutoff frequency in the acousto-optic delay line is formed due to the finite velocity of interaction of the acoustic wave with the light beam in the photoelastic medium. Two methods for measuring the cutoff frequency of the acousto-optic delay line are discussed: the method of system-parametric measurement and the method of cursor measurement. The system-parametric method for measuring the cutoff frequency of the acousto-optic delay line is implemented based on the known values of the laser beam diameter and the velocity of propagation of the acoustic wave in the photoelastic medium. The cursor method for measuring the cutoff frequency of the acousto-optic delay line is implemented based on the parameters of the oscillogram of its response to the input action in the form of a rectangular pulse. Theoretical and experimental aspects of the application of these methods are discussed. Corresponding numerical examples and experimental results are given.
subject: Research Papers
  topic: section
subject: acousto-optic
  topic: keywords
subject: delay line
  topic: keywords
subject: cutoff frequency
  topic: keywords
subject: transient response
  topic: keywords
subject: system-parametric measurement
  topic: keywords
subject: Bragg diffraction
  topic: keywords
creator: Afig Hasanov
creator: Ruslan Hasanov
creator: Elgun Aghayev
creator: Rovshan Ahmadov
rights: Copyright (c) 2026 Afig Hasanov, Ruslan Hasanov, Elgun Aghayev, Rovshan Ahmadov https://creativecommons.org/licenses/by/4.0
date: 2026-04-01
publication date: 2026-04-01
doi: 10.24423/archacoust.2026.4396

A Study of Damage Modes Recognition of Polypropylene Fiber Reinforced Recycled Aggregate Concrete Based on Principal Components of Acoustic Emission Signals
type: item
description: To investigate the principal components of acoustic emission (AE) signals and damage modes of polypropylene fiber (PPF) reinforced recycled concrete, ten groups of specimens with coarse aggregate (CA) replacement rates of 0% and 25% and different particle sizes were designed and fabricated. Uniaxial compression AE tests were conducted to obtain the AE parameters during the fracture process of PPF reinforced recycled concrete. In this study, the Pearson correlation coefficient was employed to investigate the correlations among AE parameters. Then, the principal component analysis (PCA) was performed on the AE signals to conduct dimensionality reduction of the multi-dimensional data. On this basis, the optimal number of clusters for the principal components of AE signals was determined based on the silhouette coefficient. Finally, the K-means clustering algorithm was introduced to perform cluster analysis on the principal components of AE signals of PPF reinforced recycled concrete. The clustering results were compared with each other to explore the characteristics of each cluster and identify the corresponding damage mode for each cluster. The discriminability of AE parameters with respect to damage modes was investigated, and the research findings can provide a reference for predicting the fracture mechanism of PPF reinforced recycled concrete.
subject: Research Papers
  topic: section
subject: polypropylene fiber reinforced recycled concrete
  topic: keywords
subject: acoustic emission
  topic: keywords
subject: Pearson correlation coefficient
  topic: keywords
subject: principal component analysis
  topic: keywords
subject: K-means clustering
  topic: keywords
creator: Qianxu Chen
creator: Xin Yang
rights: Copyright (c) 2026 Qianxu Chen, Xin Yang https://creativecommons.org/licenses/by/4.0
date: 2026-03-25
publication date: 2026-03-25
doi: 10.24423/archacoust.2026.4407

Modeling of High-Speed Ultrasonic Testing of Railway Rails in Track Inspection
type: item
description: In the paper the theoretical modeling of ultrasonic testing of railway rails with high scanning speed is considered. The model for the calculation of the ultrasonic field generated by the ultrasonic transducers and the pulse echo amplitude received after wave reflection at the defect is developed. The model is based on well-established principles of elastodynamic theory: the Rayleigh-Sommerfeld integral, the Auld reciprocity relation, and the Kirchhoff approximation. It forms the basis for design of computer program to simulate ultrasonic inspections of railway rails with automated mobile systems. The major innovation introduced in the model is taking into account the high scanning speed of the ultrasonic probes over the rail head and the limited repetition rate of the ultrasonic system. The mentioned aspects of the high-speed rail testing require the revision of one of the basic paradigms of the current ultrasonic models, which assume that the scanning speed of the ultrasonic probe is negligible in comparison to the speed of ultrasonic waves propagating in the tested material. Actually, when scanning rails at a speed of 120 km/h, the ultrasonic probe can change its position up to 5 mm between transmitting and receiving ultrasonic pulses reflected from defects located in the rail foot. Such a shift in probe position is not negligible and should be considered in calculations. As a consequence, the ultrasonic system's slow repetition rate and fast scanning speed can make it less likely that certain rail flaws will be found. To quantitatively examine the severity of these phenomena, the new ultrasonic model and related simulation software was developed.
subject: Technical Notes
  topic: section
subject: non-destructive testing
  topic: keywords
subject: railway rails defects
  topic: keywords
subject: testing of railway rails
  topic: keywords
subject: automatic ultrasonic testing
  topic: keywords
creator: Sławomir Mackiewicz
creator: Zbigniew Ranachowski
creator: Tomasz Katz
creator: Tomasz Dębowski
creator: Grzegorz Starzyński
rights: Copyright (c) 2026 Sławomir Mackiewicz, Zbigniew Ranachowski, Tomasz Katz, Tomasz Dębowski, Grzegorz Starzyński https://creativecommons.org/licenses/by/4.0
date: 2026-03-03
publication date: 2026-03-03
doi: 10.24423/archacoust.2026.4366

Indian Sign Language Alphabet Recognition and Speech Synthesis Using a Hybrid Deep Learning Approach
type: item
description: Indian Sign Language (ISL) is vital for communication among India's hearing-impaired community. However, the lack of standardised datasets and reliable identification frameworks has hampered the use of ISL in modern assistive technology. This paper presents a deep learning-based solution to robust ISL alphabet identification, with an emphasis on both accuracy and practical use. A curated static ISL alphabet collection was created by combining authoritative visual references from the official Indian Sign Language website and the Ramakrishna Mission Vivekananda Educational and Research Institute (RKMVERI). Multiple deep learning models were trained and assessed, including CNN, ResNet-50, DenseNet-121, VGG16, MobileNetV2, and EfficientNet-B0, with a new hybrid CNN-ResNet architecture outperforming the others. 98% classification accuracy is achieved by the suggested approach, outperforming individual baseline models. Furthermore, the framework is expanded to support real-time applications, combining webcam-based capture with immediate conversion of recognized signs to textual and synthesized vocal output. Comprehensive performance evaluation, including confusion matrix analysis and ROC curves, demonstrates the solution's durability and practical applicability. This research enhances accessibility, promotes inclusive education, and prepares the path for scalable sign language translation systems in real-world human-machine interaction scenarios by enabling accurate and real-time ISL recognition with voice feedback.
subject: Research Papers
  topic: section
subject: Indian Sign Language
  topic: keywords
subject: deep learning
  topic: keywords
subject: CNN–ResNet hybrid model
  topic: keywords
subject: real-time recognition
  topic: keywords
subject: text-to-speech
  topic: keywords
subject: assistive technology
  topic: keywords
creator: Aswani Sivan
creator: Chandra Eswaran
rights: Copyright (c) 2025 Aswani Sivan, Chandra Eswaran https://creativecommons.org/licenses/by/4.0
date: 2026-02-04
publication date: 2026-02-04
doi: 10.24423/archacoust.2026.4338

Construction Method of Sparse Dictionary for Multi-order FRFT Domain Feature Fusion
type: item
description: Reverberation constitutes a primary interference for active sonar signals, particularly the intense reverberation originating from the reflection of the incident signal. Sharing the same generation mechanism as the target echo, it severely hampers the extraction and analysis of the target signal. To enhance signal processing capabilities under strong reverberation, this paper proposes a sparse dictionary construction method based on multi-order Fractional Fourier Transform (FRFT) domain feature fusion. This method exploits the distinctive characteristics exhibited by target echoes and strong reverberation signals across different fractional transform domains to discriminate between them. It constructs sparse sub-dictionaries using these distinct fractional orders, trains the weight of each sub-dictionary via an adaptive gradient optimization strategy to achieve sparse representation of the signal, suppresses the strong interference in the sparse domain, and reconstructs the target signal through a reconstruction process, thereby achieving the goal of extracting the target signal while suppressing strong interference. Results from processing lake trial data demonstrate that the proposed method can effectively extract target echo signals amidst strong reverberation, with the signal-to-reverberation ratio improvement consistently no less than 2.1 dB and reaching up to 15.6 dB. This method provides an effective approach for the processing and analysis of weak underwater signals.
subject: Research Papers
  topic: section
subject: Underwater Acoustic Signal Processing
  topic: keywords
subject: Fractional Fourier Transform
  topic: keywords
subject: Feature Fusion
  topic: keywords
subject: Sparse Reconstruction
  topic: keywords
subject: Strong Interference Suppression
  topic: keywords
creator: Tongjing Sun
creator: Lei Chen
creator: XiaoHong Deng
rights: Copyright (c) 2026 Tongjing Sun, Lei Chen, XiaoHong Deng https://creativecommons.org/licenses/by/4.0
date: 2026-03-10
publication date: 2026-03-10
doi: 10.24423/archacoust.2026.4408

Causality- and Passivity-Constrained Nonnegative Attention for Interpretable Structure-Borne Road-Noise Prediction in Battery Electric Vehicles
type: item
description: In battery electric vehicles, structure-borne road noise in the 20–300 Hz band becomes more audible because the engine-masking component is largely absent, and conventional transfer-path formulations can be sensitive to suspension nonlinearity and ill-conditioned inversions. This paper presents a physics-informed non-negative multi-modal fusion network (NN-MMFNet) that predicts in-cabin sound pressure from multi-point chassis excitations while keeping the mapping physically plausible and interpretable. The model combines a dual-stream encoder to separate transient impact signatures from steady resonance content with a strictly causal fusion/decoding pathway. A passivity-motivated spectral gain cap is applied to prevent non-physical amplification while preserving phase. To enable additive path attribution, the cross-modal attention weights are constrained to be non-negative. Training follows a sim-to-real workflow, using virtual-fleet pretraining and short fine-tuning on measured data. On a production BEV, NN-MMFNet reproduces the 20–300 Hz spectrum with a 1.12 dB(A) global RMSE at 60 km/h and a 0.14 dB error at the 128 Hz boom, outperforming TPA/FTM/ARMA baselines. Impulse-response checks show negligible passivity-violation rate (<0.01%). The learned attention consistently points to a rear subframe-to-body mounting path near 128 Hz, and a targeted stiffness adjustment at this location reduces the measured cabin noise by 4.2 dB(A).
subject: Research Papers
  topic: section
subject: structure-borne road noise
  topic: keywords
subject: physics-informed neural networks (PINN)
  topic: keywords
subject: transfer path analysis (TPA)
  topic: keywords
subject: cross-modal attention
  topic: keywords
subject: battery electric vehicles (BEVs)
  topic: keywords
creator: Haijun Wang
creator: Zhijie Huang
creator: Zengjun Lu
creator: Xianghua He
creator: Tie Xu
rights: Copyright (c) 2026 Haijun Wang, Zhijie Huang, Zengjun Lu, Xianghua He, Tie Xu https://creativecommons.org/licenses/by/4.0
date: 2026-03-19
publication date: 2026-03-19
doi: 10.24423/archacoust.2026.4403

Dispersion Characteristics of SH waves in a Rotating Micro-structured Plate with Restrained Boundaries
type: item
description: Shear horizontal (SH) waves in plates are elastic stress disturbances that propagate along bounded surfaces, with in-plane shear motion perpendicular to the propagation direction, influenced by physical, geometric, and boundary conditions. Due to their sensitivity to surface and subsurface defects, SH waves are widely employed in non-destructive testing (NDT), structural health monitoring (SHM), and material characterization. This study presents a theoretical investigation of SH-wave propagation in a rotating, microstructural elastic plate within the framework of Consistent Couple Stress Theory (CCST), incorporating elastically restrained boundary conditions. CCST introduces a characteristic length parameter to account for microstructural and size-dependent effects beyond classical elasticity. Restrained boundaries provide an intermediate model between idealized traction-free and rigid conditions, capturing realistic boundary behavior encountered in practical applications. An analytical dispersion relation is derived to examine the combined effects of boundary restraints, microstructural parameters, and rotational speed on SH-wave dispersion, with several special cases presented to validate the general formulation. Graphical results illustrate the influence of restraint stiffness, characteristic length, plate thickness, and rotation on SH-wave dispersion characteristics. The findings offer valuable insights for the design of advanced sensing devices, the development of non-destructive evaluation techniques, and the analysis of seismic wave propagation in rotating geophysical layers.
subject: Research Papers
  topic: section
subject: SH waves
  topic: keywords
subject: Couple stress theory
  topic: keywords
subject: Stiffness coefficients
  topic: keywords
subject: Restrained boundary conditions
  topic: keywords
subject: Dispersion curves
  topic: keywords
subject: Rotating elastic plate
  topic: keywords
creator: Mandeep Kaur
creator: Satish Kumar
creator: Vikas Sharma
rights: Copyright (c) 2026 Mandeep Kaur, Satish Kumar, Vikas Sharma https://creativecommons.org/licenses/by/4.0
date: 2026-04-16
publication date: 2026-04-16
doi: 10.24423/archacoust.2026.4395

Flanking Sound Transmission in Massive-Lightweight Connections
type: item
description: Assessing the impact of flanking sound transmission is one of the most significant challenges in the process of designing building partitions. Acoustic parameters declared by manufacturers of lightweight systems are subject to errors of up to several decibels – and in the case of inaccurate construction on site, these differences can reach even higher values. One factor contributing to this is the phenomenon known as flanking sound transmission, which involves the transmission of acoustic energy through partitions connected to the partition directly dividing two adjacent rooms. For this reason, estimating the resultant acoustic insulation of a partition, taking flanking paths into account, is crucial at an early stage of the design process to ensure compliance with the requirements outlined in standard recommendations, and the literature. Currently, there are regulations and studies that provide guidance on calculating the estimated reduction in acoustic insulation due to flanking transmission. However, in practice, situations arise that have not yet been addressed in standards or the literature. Examples include partitions made of plasterboard, which are among the most common types of partition walls in Poland, yet are not covered by current normative procedures, as well as glass systems. This study aims to further explore this topic by analysing the impact of combining a massive partition with flanking lightweight partitions for selected structures (glass, plasterboard with single or double panelling, with full or partial sound-absorbing material infill, and without infill) and connection types.
subject: OSA 2025
  topic: section
subject: building acoustics
  topic: keywords
subject: flanking sound transmission
  topic: keywords
subject: sound insulation
  topic: keywords
subject: statistical energy analysis
  topic: keywords
creator: Agnieszka Wójtowicz
creator: Tadeusz Kamisiński
creator: Jarosław Rubacha
rights: Copyright (c) 2026 Agnieszka Wójtowicz, Tadeusz Kamisiński, Jarosław Rubacha https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 223
ending page: 232
doi: 10.24423/archacoust.2026.4330

Study on Dual-Stage Amplification Cascaded Piezoelectric Transducer for High-Power Applications
type: item
description: To reduce the size and enhance the efficiency of cascaded sandwich transducers with conical horns, a novel structural configuration of such transducers is investigated. This transducer incorporates two sets of piezoelectric stacks, enabling two-stage amplification to improve efficiency. An equivalent circuit model of the cascaded sandwich transducer with a conical horn is established, and analytical expressions for key performance parameters, including input impedance, velocity amplification ratio, and resonant characteristics, are systematically derived. Through theoretical and simulation analyses, the dynamic influence of key structural parameters on electromechanical energy conversion efficiency is determined, specifically including the output radius of the second stage, the relative position of the variable cross-sections of two sets of piezoelectric ceramic sandwich structures, and the spacing between the two sets of piezoelectric stacks. Furthermore, a performance optimization strategy based on piezoelectric single-crystal materials is proposed. Numerical simulation results, validated against the theoretical models, reveal the governing principles of piezoelectric material properties on transducer performance. Experimental results demonstrate excellent agreement between the operational characteristics of the optimized transducer and predictions obtained from both theoretical models and finite element simulations. This work provides significant guidance for the optimization of multi-mode transducers and demonstrates promising application potential in high-power ultrasonic fields.
subject: Research Papers
  topic: section
subject: cascaded transducer
  topic: keywords
subject: multi-mode
  topic: keywords
subject: velocity amplification ratio
  topic: keywords
subject: finite element analysis
  topic: keywords
creator: Guo Li
creator: Peiyu Tan
creator: Ruihui Ma
creator: Feilong Li
creator: Xiaoli Zhang
creator: Hua Tian
rights: Copyright (c) 2026 Guo Li, Peiyu Tan, Ruihui Ma, Feilong Li, Xiaoli Zhang, Hua Tian https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 145
ending page: 159
doi: 10.24423/archacoust.2026.4275

In Memoriam Professor Eugeniusz Kozaczka
type: item
description: Professor Eugeniusz Tadeusz Kozaczka, member of the Polish Academy of Sciences, passed away on May 27, 2025, in Gdynia. We write these words with profound sorrow and deep regret, mourning the loss of such an exceptional person as Professor Eugeniusz Kozaczka.
subject: In Memoriam
  topic: section
creator: Bogumił LINDE
creator: Iwona KOCHAŃSKA
rights: Copyright (c) 2025 https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 419
ending page: 420
doi: 10.24425/aoa.2025.157220

Impact of Perforated Sheet Geometry on the Insertion Loss of Absorption Silencers
type: item
description: This study evaluates the influence of perforated sheet geometry on the acoustic and aerodynamic performance of absorption silencers. A modular silencer was developed, enabling the installation of six different perforated metal sheets with varying hole shapes (round, square, elongated), sizes (2-20 mm), and open area ratios (22-45%). Glass wool was used as the sound-absorbing filling. Insertion loss, self-noise, and pressure drop were measured in a large reverberation chamber, within the frequency range 50-10,000 Hz, for airflow velocities of 4, 6, and 8 m/s. The results indicate that all configurations provide comparable attenuation at low frequencies. Silencers with small round perforations (diameter 2-6 mm) ensured higher insertion loss and lower self-noise in the 1,000-5,000 Hz mid-frequency range, without any measurable increase in pressure drop compared to variants with larger or elongated holes. For frequencies above 6,300 Hz, perforated sheets with larger holes performed better. Pressure loss differences between all configurations did not exceed 1 Pa at a given flow velocity. The results confirm that aperture size is the primary parameter affecting silencer acoustic effectiveness, while aperture shape and perforation ratio are secondary. These findings provide practical guidelines for optimal silencer design in ventilation systems, ensuring maximum noise reduction with minimal airflow resistance.
subject: OSA 2025
  topic: section
subject: silencers
  topic: keywords
subject: insertion loss
  topic: keywords
subject: experimental test
  topic: keywords
subject: aeroacoustics
  topic: keywords
subject: ventilation
  topic: keywords
creator: Kamil Wójciak
creator: Joanna Maria Kopania
creator: Patryk Gaj
rights: Copyright (c) 2026 Kamil Wójciak, Joanna Maria Kopania, Patryk Gaj https://creativecommons.org/licenses/by/4.0
date: 2026-03-26
publication date: 2026-03-26
doi: 10.24423/archacoust.2026.4332

Analysis on Modal Distribution and Modal Density-Based Crossover Frequency in Cabin-Sized Enclosures
type: item
description: In the sound field simulation of cabin-sized enclosures, the Schroeder frequency (SF) is still employed to estimate the crossover frequency (CF) that determines the validity ranges of wave-based and geometrical acoustic methods. However, because cabin-sized enclosures exhibit distinct modal behaviors from typical medium- and large-scale rooms, the validity of SF in such enclosures has not been thoroughly tested. This study introduces the modal density-based crossover frequency (MDCF) to systematically evaluate the applicability of SF in cabin-sized enclosures. The MDCF employs the same dense modal criterion as SF. However, its modal parameters, are derived from the numerical eigenfrequency analysis. This contrasts with the SF formula, where these parameters are determined solely by the room volume and reverberation time. Ten models are constructed for evaluation, grouped into two volume sets: 8 m3 (cabin-sized) and 80 m3 (common-sized). Each set comprises five distinct geometrical shapes from rectangular models to simplified vehicle shapes. The results reveal that, for cabin-sized enclosures under low absorption boundary conditions, the MDCF is typically 70 Hz to 150 Hz lower than SF; the discrepancies decrease to 20 Hz to 50 Hz in 80 m3 rooms. Furthermore, the MDCF varies with room shapes at a constant volume, while the SF remains nearly unchanged. These findings demonstrate that MDCF provides a more reliable CF estimation for rooms with irregular shapes, highlighting the importance of considering accurate modal parameters in the acoustic analysis of cabin-sized models.
subject: Research Papers
  topic: section
subject: vehicle acoustics
  topic: keywords
subject: room acoustic modes
  topic: keywords
subject: crossover frequency
  topic: keywords
subject: Schroeder frequency
  topic: keywords
creator: Ziyu Wang
creator: Liangfen Du
creator: Guangzheng Yu
rights: Copyright (c) 2026 Ziyu Wang, Liangfen Du, Guangzheng Yu https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 25
ending page: 36
doi: 10.24423/archacoust.2026.4290

TimeGAN and Coordinated Attention Prototype Network Based Prediction Model for Infrasound Signal
type: item
description: Due to the complexity of the infrasound environment and the high costs associated with data collection, frequent acquisition of infrasound data is often impractical, resulting in a limited amount of labeled data. To address the challenge of low classification prediction accuracy caused by data scarcity, this paper proposes an infrasound prediction model based on a time-series generative adversarial network (TimeGAN) and coordinated attention prototype network (CAPN) (TimeGAN-CAPN). The model begins by introducing TimeGAN, where the generative network is trained using a combination of unsupervised and supervised learning. This approach enables the network to operate within the latent space of temporal features and generate time-series data that closely aligns with the distribution of the original data. These generated samples are then combined with the original data to form an augmented dataset. Subsequently, the augmented data is input into the CAPN, which enhances the sample size per class, allowing for more precise class prototypes and improving the prediction accuracy of the model. Furthermore, the quality and diversity of the data generated by TimeGAN are quantitatively and qualitatively assessed using maximum mean discrepancy (MMD) and t-distributed stochastic neighbor embedding (t-SNE), facilitating a comparison and verification of the generated data’s performance. Experimental results show that TimeGAN-CAPN significantly outperforms the CAPN model in classification tasks with limited infrasound data, achieving an increase in accuracy of 7.15 %. This demonstrates that the proposed method is highly effective for predicting infrasound-related disasters, particularly in scenarios with small sample sizes.
subject: Research Papers
  topic: section
subject: infrasound signal
  topic: keywords
subject: time-series generative adversarial network
  topic: keywords
subject: coordinated attention prototype network
  topic: keywords
subject: maximum mean discrepancy
  topic: keywords
subject: other
  topic: disciplines
creator: Quanbo Lu
creator: Xiaojuan Huang
creator: Rao Li
creator: Mei Li
creator: Dong Zhu
rights: Copyright (c) 2026 Quanbo Lu, Xiaojuan Huang, Rao Li, Mei Li, Dong Zhu https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 37
ending page: 55
doi: 10.24423/archacoust.2026.4229

An Empirical Approach to Investigate Environmental Effects on Acoustic Signal Speed in Oceanic Layers
type: item
description: This paper investigates and demonstrates the effects of three significant environmental contributors: temperature, depth and salinity impact on the acoustic signal propagation across distinctive ocean layers: mixed, thermocline, and deep layers. In the field of underwater wireless sensor networks (UWSN), exact and precise determination of coordinates for sensor localization is very crucial for data validation. Temperature dominates the upper layers; depth becomes the prime factor for the deeper domain with minimal thermal variations. Salinity while having a diminished effect, facilitates minor changes in propagation and deviation of acoustic signal speed. In our work we have analyzed these interdependencies by using different empirical models (e.g., Mckenzie, Medwin) customized to each layer, accounting to their incomparable environmental parameters. In mixed layers, changes in sound speed are mainly caused by thermal factors, where depth is of minimal importance, and the influence of salinity is insignificant, but with increasing depth, the temperature begins to decrease, and depth (pressure) begins to become important, and changes in salinity and temperature become almost equivalent. By evaluating ocean layer specified empirical formulas, we have calculated the average speed of sound and measure the corresponding contribution of all parameters. Our work has provided a substructure which helps to optimize the identification or localization of UWSN nodes. The results of this work underscored the essential to have an adaptive sound speed modeling in order to achieve enhanced and precise acoustic signal communication systems.
subject: Research Papers
  topic: section
subject: acoustic signal speed
  topic: keywords
subject: ocean layers
  topic: keywords
subject: salinity
  topic: keywords
subject: empirical formulas
  topic: keywords
subject: sound speed modeling
  topic: keywords
creator: Khondoker Munim Salehin
creator: Md. Khalid Mahbub Khan
creator: Anisur Rahman
rights: Copyright (c) 2026 Khondoker Munim Salehin, Md. Khalid Mahbub Khan, Anisur Rahman https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 107
ending page: 130
doi: 10.24423/archacoust.2026.4369

Ultrasonic Estimation of Pressure Dependent Non-Linearity Index in Liver
type: item
description: This study introduces a proof-of-concept methodology for evaluating pressure-dependent non-linear acoustic properties of liver tissue. The proposed non-linearity index (NLI) is derived from echo amplitudes obtained at two substantially different acoustic pressures. Unlike previous harmonic-based approaches, the method relies solely on the fundamental frequency band, allowing clinical implementation without additional system modifications. The image acquired for the lower pressure is then amplified to correct for the pressure difference between the beams. Next, the NLI is estimated as a ratio of local amplitudes of the amplified low-pressure image (ALPI) to the high-pressure image (HPI). In the case of nonlinear media some energy of the wave is transferred from the pulse fundamental frequency to higher harmonics, which affects mainly the HPI. With the harmonics being filtered out from the signal, the HPI amplitude becomes lower than the ALPI amplitude. As a result, the NLI becomes higher than 1 and increases with the non-linearity of the imaged tissue. The hydrophone measurements were compared to the simulation (k-Wave) of the ultrasonic field in water and vegetable oil. Next, we performed NLI imaging of healthy and fatty livers using SonixTouch (Ultrasonix) systems and two acoustic pressures of 390 kPa and 1590 kPa. Preliminary studies – imaging healthy and fatty livers using SonixTouch (Ultrasonix) systems were performed on the 4 livers of the authors of the article showed that for ‘healthy’ livers the NLI was below 1.1, while in one of the authors with previously diagnosed steatosis falling between score 1 and 2, the NLI locally exceeded 1.3. These results show that the obtained NLI values increase with the degree of steatosis, which agrees with theoretical expectations based on tissue B/A coefficients. The work emphasizes methodological feasibility and physical consistency rather than clinical validation, given the limited number of volunteers and ethical restric…
subject: Research Papers
  topic: section
subject: ultrasound imaging
  topic: keywords
subject: abdominal ultrasound
  topic: keywords
subject: non-linear propagation
  topic: keywords
creator: Andrzej Nowicki
creator: Jurij Tasinkiewicz
creator: Piotr Karwat
creator: Norbert Żołek
creator: Ihor Trots
creator: Ryszard Tymkiewicz
rights: Copyright (c) 2026 Andrzej Nowicki, Jurij Tasinkiewicz, Piotr Karwat, Norbert Żołek, Ihor Trots, Ryszard Tymkiewicz https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 93
ending page: 105
doi: 10.24423/archacoust.2026.4363

Few-Shot Transfer for Speech Enhancement Using SEGAN with Stability Guardrails
type: item
description: High-quality speech communication is often compromised by background noise, reducing intelligibility and perceived quality. We investigate data-efficient few-shot transfer of a Speech Enhancement Generative Adversarial Network (SEGAN) to a new noise domain. Starting from a generator pretrained on VoiceBank–DEMAND, we adapt the model to MiniLibriMix using only 300 paired noisy–clean examples. To prevent overfitting and catastrophic forgetting, we introduce SAFE (Stable Adversarial Few-shot Enhancement), a three-fold stabilisation strategy with (i) exponential-moving-average (EMA) weight averaging, (ii) L2-SP weight anchoring to the source-domain parameters, and (iii) a teacher–student consistency loss. SAFE maintains VoiceBank performance (PESQ ≈ 1.84; STOI ≈ 90 %) and, after an optional perceptual fine-tuning stage (MR-STFT + adversarial), yields substantial target-domain gains on MiniLibriMix (PESQ 1.11 → 1.26, STOI 71.5 % → 81.5 %) with only a minor source-domain trade-off in STOI. Ablation experiments demonstrate that EMA provides the strongest stabilising effect, while L2‑SP and consistency regularisation offer complementary benefits. These results suggest that stable few‑shot adaptation can make lightweight time‑domain speech enhancers practical for rapid deployment in novel acoustic environments.
subject: Research Papers
  topic: section
subject: speech enhancement
  topic: keywords
subject: generative adversarial networks
  topic: keywords
subject: few-shot learning
  topic: keywords
subject: transfer learning
  topic: keywords
subject: domain adaptation
  topic: keywords
subject: stability regularization
  topic: keywords
creator: Rubi Sharma
creator: Firos A.
rights: Copyright (c) 2026 Rubi Sharma, Firos A. https://creativecommons.org/licenses/by/4.0
date: 2026-03-10
publication date: 2026-03-10
doi: 10.24423/archacoust.2026.4315

Application of Acoustic Metamaterials in the Design of Muffling Unit of Internal Combustion Engine
type: item
description: Aiming at the problems of large volume, high exhaust resistance and difficulty in suppressing noise in the 500 Hz to 100 Hz frequency band of traditional internal combustion engine exhaust mufflers, a noise reduction unit design based on acoustic metamaterials is proposed. Based on the equivalent medium theory, an acoustic model with a ring structure and multi-region variable refractive index was established. Phase control is achieved by helically winding the acoustic channel to change the refractive index, and the basic dimensions of the acoustic metamaterial muffling unit are calculated. The sound field distribution, transmission loss and flow field characteristics of the muffling unit are simulated and analyzed. This structure utilizes a multi-layer acoustic channel structure, effectively alleviating the problem of insufficient low-frequency noise elimination caused by the asymmetry of Fano interference. It achieved a transmission loss of over 10 dB within 85 % of the 500 Hz to 1000 Hz frequency band, and still maintained excellent noise reduction performance under high-frequency conditions through multi-level phase control. By connecting multiple units in series, a transmission loss of 10 dB can be achieved within 85 % of the 500 Hz to 1000 Hz frequency band. The exhaust flow field of the muffling unit was simulated and analyzed. Whether used alone or in series with the traditional muffling structure, the exhaust resistance remained within the range of 360 Pa to 370 Pa. Experimental tests show that when the metamaterial muffler unit is used in combination with the traditional muffler, it effectively achieves targeted noise elimination in the 500 Hz to 1000 Hz frequency band, and also demonstrates clear noise reduction capabilities in higher frequency ranges. The high noise suppression characteristics, high gas passage characteristics and compact volume characteristics of this structure provide more potential analysis methods and design schemes for the research a…
subject: Research Papers
  topic: section
subject: acoustic metamaterials
  topic: keywords
subject: muffler
  topic: keywords
subject: transmission loss
  topic: keywords
subject: exhausting resistance
  topic: keywords
subject: noise and vibration
  topic: disciplines
creator: Tianshuo Li
creator: Lei Zheng
creator: Zhengyang Bi
creator: Hongchao Ji
rights: Copyright (c) 2026 Tianshuo Li, Lei Zheng, Zhengyang Bi, Hongchao Ji https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 3
ending page: 23
doi: 10.24423/archacoust.2026.4190

Subwavelength Underwater Imaging of a Wire Array Metamaterial Based on Fabry–Perot Resonance
type: item
description: Metamaterials with Fabry–P´erot (FP) resonance have proven effective for underwater ultrasound imaging. The propagation phenomenon can be understood as a spatial filter with linear dispersion over a finite bandwidth. However, conventional imaging techniques are constrained by the diffraction limit or rely on a strong impedance mismatch between the metamaterial and water. In this paper, we propose a columnar array metamaterial designed for underwater imaging based on FP resonances and validate the proposed design through numerical simulations. The acoustic pressure transmission coefficient, together with the normalized acoustic pressure distribution, is analyzed to quantitatively evaluate imaging quality and verify the physical effectiveness of the model. This novel structure enables deep subwavelength imaging underwater, maintaining excellent and stable imaging performance within a 0.4 kHz bandwidth centered around the operating frequency. We use air-filled metamaterials to create strong acoustic coupling and establish effective sound isolation. This approach significantly enhances imaging resolution, while optimizing energy loss at multiple interfaces, an issue in previous studies. Additionally, in contrast to resonance- or refraction-based approaches such as Helmholtz resonators or hyperlens designs, the proposed FP-resonant metamaterial offers an alternative mechanism for achieving near-field subwavelength imaging through controlled wave transmission and confinement. We also examine the influence of various parameters, such as imaging distance, incidence distance, and array periodicity, on imaging performance. The results demonstrate that the columnar array metamaterial holds great potential for underwater ultrasound imaging applications.
subject: Research Papers
  topic: section
subject: Fabry–P´erot (FP) resonance
  topic: keywords
subject: metamaterial underwater imaging
  topic: keywords
subject: air-filled metamaterials
  topic: keywords
subject: finite element simulation
  topic: keywords
subject: underwater acoustics
  topic: disciplines
creator: Guo LI
creator: FeiLong LI
creator: LiQing HU
creator: QunFeng LI
creator: GuanJun YIN
rights: Copyright (c) 2025 Guo LI, FeiLong LI, LiQing HU, QunFeng LI, GuanJun YIN https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 477
ending page: 490
doi: 10.24425/aoa.2025.156930

Similarity Analysis and Target Strength Correction of Non-Proportional Scaled Models Based on Highlight Model Theory
type: item
description: Acoustic scattering scale models often fail to meet the acoustic similarity design requirements due to limitations in fabrication technology, testing facilities, and safe transportation, which restrict the accurate extrapolation of acoustic scattering characteristics between scaled models and full-scale ships. To overcome this challenge, the present study applies highlight model theory to perform acoustic similarity analysis and to correct the local target strength of simple objects in the model based on overall acoustic scattering correction. A novel method for correcting the target strength of non-proportional scaled models is proposed. The method is validated using various model geometries, including ellipsoids, finite-length cylinders, truncated elliptical cones, and complex structures. Additionally, the plate element method is employed for target strength correction and scaling conversion analysis for non-proportional scaled models. The study highlights the variation in target strength due to changes in geometric dimensions and demonstrates the effectiveness of the proposed correction method. The results indicate that the proposed correction approach allows for more accurate extrapolation of target strength from non-proportional scaled models to full-scale prototypes, thereby better satisfying the requirements of practical engineering applications.
subject: Technical Notes
  topic: section
subject: acoustic scattering
  topic: keywords
subject: similarity theory
  topic: keywords
subject: highlight theory
  topic: keywords
subject: scaled model
  topic: keywords
creator: Jin Zhang
creator: Zhenyu Li
creator: Yinhao Li
creator: Zilong Peng
rights: Copyright (c) 2026 Jin Zhang, Zhenyu Li, Yinhao Li, Zilong Peng https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 183
ending page: 196
doi: 10.24423/archacoust.2026.4286

Application of ISO 12913 Standard to Assess Urban Soundscapes: A Case Study on Poznań
type: item
description: ISO 12913 standards provide a unified framework for describing and assessing soundscapes, however, the lack of a Polish translation has so far limited their practical use. This paper presents the first application of a validated Polish version of the ISO/TS 12913-2 perceptual attributes, enabling full cross-language comparability of results. Whereas Polish research has traditionally focused on noise annoyance and broad judgements of acoustic comfort or discomfort, we outline the complete ISO-compliant assessment procedure, which combines: a soundwalk, questionnaires and audio-visual recording. The study was conducted at eight diverse urban locations in Poznań, Poland. Participants rated the soundscapes using eight attributes: przyjemne, tętniące życiem, bogate w wydarzenia, chaotyczne, dokuczliwe, monotonne, ubogie w wydarzenia, spokojne. Each rating set is mapped to a point in the 2D pleasantness-eventfulness space defined in ISO/TS 12913-3, facilitating visual comparison of locations and the identification of design needs. Results reveal pronounced perceptual differences between spatial typologies and demonstrate that the standardized approach provides richer, multidimensional information about the acoustic environment than conventional noise indicators. The proposed methodology establishes a reference framework for Polish soundscape studies and can support the creation of more people-friendly urban acoustic environments.
subject: OSA 2025
  topic: section
subject: soundscape
  topic: keywords
subject: ISO 12913
  topic: keywords
subject: Polish translation
  topic: keywords
subject: soundwalk
  topic: keywords
subject: perceptual attributes
  topic: keywords
creator: Jakub Dumanowski
creator: Anna Preis
creator: Jan Felcyn
rights: Copyright (c) 2026 Jakub Dumanowski, Anna Preis, Jan Felcyn https://creativecommons.org/licenses/by/4.0
date: 2026-01-30
publication date: 2026-01-30
doi: 10.24423/archacoust.2026.4337

Single-Sensor Passive Ranging of Underwater Monopoles Using Near-Field/Far-Field Energy Contrasts
type: item
description: While acoustic vector sensors (AVS) are well-established for detection and direction-of-arrival (DOA) estimation using co-located pressure and particle motion (PM) measurements, their potential for passive range estimation remains largely unexplored. This paper introduces a novel single-AVS method for passive range estimation to an acoustic monopole source by exploiting the fundamental near-field dominance of PM energy. We derive the frequency and the distance dependent ratio (ξ) of kinetic to potential acoustic energy density – a key near-field signature inaccessible to conventional hydrophones. By leveraging simultaneous AVS pressure and PM velocity measurements, our method estimates ξ, inverts the monopole near-field model to obtain the Helmholtz number, and directly computes the range. Crucially, we demonstrate that PM sensors offer a potential signal-to-noise ratio (SNR) advantage over pressure sensors within the near-field (>7.8 dB). Validation under simulated noise conditions shows accurate range estimation (RMSE <10 %) for low-frequency sources (<100 Hz) within 8 m–25m ranges at 0 dB SNRs, with performance degrading as frequency increases or SNR decreases. Critically, robustness is confirmed using recorded basin noise profiles, overcoming the isotropic Gaussian noise assumption. This technique extends AVS functionality beyond DOA, enabling single-sensor passive ranging without arrays, environmental priors, or reference signals where conventional methods fail.
subject: Research Papers
  topic: section
subject: monopole source
  topic: keywords
subject: passive ranging
  topic: keywords
subject: acoustic vector sensor (AVS)
  topic: keywords
subject: particle motion (PM)
  topic: keywords
subject: near-field acoustics
  topic: keywords
subject: underwater acoustics
  topic: keywords
subject: energy ratio
  topic: keywords
subject: single-sensor localization
  topic: keywords
creator: Saier MAHMOUD
creator: Louay SALEH
creator: Ibrahim CHOUAIB
rights: Copyright (c) 2025 Saier MAHMOUD, Louay SALEH, Ibrahim CHOUAIB https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 491
ending page: 499
doi: 10.24425/aoa.2025.154829

Analysis of Decision Fusion in Speech Detection
type: item
description: This article addresses the issue of detecting speech signal segments in an acoustic signal and analyzes potential decision fusion for a group of voice activity detectors (VADs). We designed ten new VADs using three different types of neural network architectures and three time-frequency signal representations. One of the proposed models has higher classification efficiency than competitive solutions. We used our VAD models to analyse data fusion and improve the final classification decision. For this purpose, we used gradient-free and gradient-based optimizers with different objective functions. The analysis revealed the impact of individual classifiers on the final decisions and the potential gains or losses resulting from VAD fusion. Compared with existing models, the models we proposed achieved higher classification accuracy at the cost of increased memory requirements. The final choice of a specific model depends on the platform constraints on which the VAD system will be deployed.
subject: Research Papers
  topic: section
subject: voice activity detection (VAD)
  topic: keywords
subject: deep neural networks
  topic: keywords
subject: data fusion
  topic: keywords
subject: other
  topic: disciplines
creator: Tomasz MAKA
creator: Lukasz SMIETANKA
rights: Copyright (c) 2025 Tomasz MAKA, Lukasz SMIETANKA https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 445
ending page: 454
doi: 10.24425/aoa.2025.156933

Active Vibration Suppression of a Thin Circular Pipe
type: item
description: The article presents an active vibration damping system for a thin-walled cylindrical tube, which is a simplified model of a lightweight robot (LWR) arm. The proposed solution integrates control algorithms, piezoelectric materials and a hardware and software environment enabling real-time control. Macro fiber composite (MFC) elements were used for active vibration reduction, acting simultaneously as sensors and actuators. The object on which the research was conducted was a tube with an external diameter of 40 mm, this element was rigidly mounted at a distance of 1 meter from the free end, simulating cantilever conditions. The stimulation of the object to vibration was carried out using the MFC actuator, while the system response was recorded in the xPC Target environment. Based on the measurement data, the mathematical model of the object was identified in the discrete domain using the ARX method. The obtained model was used to design a controller based on the pole location method, which was implemented on a real test stand. The experimental results showed the effectiveness of the designed control system in reducing the amplitude of natural vibrations of the structure. The use of MFC elements as sensor elements and actuators enabled effective vibration damping in real time, confirming the usefulness of the proposed solution in the context of improving the precision of robotic systems.
subject: OSA 2025
  topic: section
subject: active vibration control
  topic: keywords
subject: lightweight robot arm
  topic: keywords
subject: Macro Fiber Composite
  topic: keywords
subject: PID controller
  topic: keywords
subject: system identification
  topic: keywords
subject: piezoelectric actuators
  topic: keywords
creator: Marcin Pater
creator: Lucyna Leniowska
creator: Marcin Grochowina
rights: Copyright (c) 2026 Marcin Pater, Lucyna Leniowska, Marcin Grochowina https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 211
ending page: 222
doi: 10.24423/archacoust.2026.4329

The influence the surface of ventilation duct on sound attenuation in the airflow
type: item
description: These studies focus on acoustical parameters of steel flat-oval ducts in dependence on their roughness. The four types of steel ducts were measured: raw steel, galvanised steel, painted steel, and aluminium as the reference one. The roughness of the duct was measured, and roughness parameters were specified. The sound power level was obtained on the specially constructed stand test with an outlet to the reverberation room. Insertion loss to evaluate the acoustic attenuation performance of the studied steel ducts was obtained. In the present study, an aluminium duct, which is very smooth with minimal airflow friction, was treated as a low-noise object (“silencer”). These studies have shown that for each of the tested steel ducts, the self-noise is higher than for the aluminium duct. The largest differences in this self-noise were observed at a velocity of 12 m/s for the galvanised duct and the raw steel duct compared to the aluminium duct. Insertion losses in straight ducts are consistent with literature and are very low for flat-oval steel ducts. Aluminium duct performs better acoustically than the other ducts studied at lower velocities; however, as airflow velocity increases, the differences in acoustic performance between the materials become less pronounced. That suggests that aerodynamic effects dominate over material surface treatments at higher velocities.
subject: Research Papers
  topic: section
subject: steel duct
  topic: keywords
subject: roughness
  topic: keywords
subject: insertion loss
  topic: keywords
subject: HVAC
  topic: keywords
creator: Joanna Maria Kopania
creator: Kamil Wójciak
creator: Patryk Gaj
creator: Grzegorz Bogusławski
rights: Copyright (c) 2026 Joanna Maria Kopania, Kamil Wójciak, Patryk Gaj, Grzegorz Bogusławski https://creativecommons.org/licenses/by/4.0
date: 2026-03-31
publication date: 2026-03-31
doi: 10.24423/archacoust.2026.4328

The Impact of Generated and Expressive Modulation of the Synthetic Instrument Sound Parameters on the Impression of Naturalness
type: item
description: Despite their different spectral structures, the sound of early instruments from the electrophone group was often considered to be deceptively similar to the sound of wind or bowed string instruments. However, the wavetable synthesizer playing a short, looped sample of a natural instrument is easily distinguishable from the actual instrument. This results from the presence of specific modulatory structures in the sound of some instruments related to expression, which can be a strong clue regarding the identification of the instrument. The control of early electrophones, such as the theremin or Martenot waves, gave the performer expressive capabilities comparable to bowed instruments. Contemporary synthesizers are returning to similar solutions. The aim of this work is to study the impact of various types of modulation on the perceived naturalness of violin sound. Modulation through an automatic low frequency oscillator is compared to expressive modulation by a human using a controller. Two advanced controllers are studied to determine whether simultaneous modulation of more than one parameter brings benefits. A set of sound samples was prepared that included violin recordings and synthesized signals, where different waveforms were combined with various modulation sources and modulated parameters. The effect was assessed by a group of expert listeners. The results indicate that expressive, multi-parameter modulation with advanced controllers brings benefits for waveforms with realistic spectra, close to that of a violin. In less realistic waveforms this kind of modulation may be perceived as less natural than a simple one, obtained through an oscillator.
subject: OSA 2025
  topic: section
subject: sound synthesis
  topic: keywords
subject: signal modulation
  topic: keywords
subject: expressive performance
  topic: keywords
subject: expressive controller
  topic: keywords
creator: Marek Janusz Pluta
rights: Copyright (c) 2026 Marek Janusz Pluta https://creativecommons.org/licenses/by/4.0
date: 2026-03-11
publication date: 2026-03-11
doi: 10.24423/archacoust.2026.4327

Potential Applications of Ultrasonic Parametric Array Loudspeakers (PALs) in Room Acoustic Measurements
type: item
description: In this paper, the potential use of parametric array loudspeakers (PALs) in acoustic measurements of the room is analysed, especially in the assessment of the effectiveness of reflective panels and intentionally angled surfaces. PALs are sound sources capable of emitting highly directional acoustic beams within the audible frequency range. Their operation is based on the emission of a high-frequency (ultrasonic) carrier modulated so that, through nonlinear demodulation in air, audible sound is generated. This process results in a narrow, focused sound beam, enabling precise acoustic emission. To explore PALs potential for acoustic measurement applications, the propagation behaviour of PAL-generated signals is first investigated under free-field conditions, focusing on how different surface types influence sound reflection. Subsequent experiments are carried out in a controlled indoor space, where impulse responses are recorded for various beam incidence angles and receiver positions. The collected data are used to generate sound-level distribution maps, allowing for the visualization and quantification of reflected sound coverage areas. The results show that PALs produce beams with substantially reduced lateral dispersion compared to conventional loudspeakers, enabling precise identification of reflection points and incidence angles. This directional precision makes it possible to accurately assess how effectively the reflective acoustic elements and structures shape the sound field within the room. Overall, these findings may contribute to optimising sound design in acoustically complex environments.
subject: OSA 2025
  topic: section
subject: parametric array loudspeakers (PALs)
  topic: keywords
subject: room acoustics
  topic: keywords
subject: ultrasonic
  topic: keywords
subject: reflection
  topic: keywords
subject: directivity
  topic: keywords
creator: Filip WĘGRZYN
creator: Adam PILCH
rights: Copyright (c) 2025 Filip WĘGRZYN, Adam PLICH https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 513
ending page: 524
doi: 10.24425/aoa.2025.156934

Cube-Shaped Sound-Insulating Enclosures: Experimental Tests and Calculation Models
type: item
description: The research described in this article concerns sound-insulating enclosures used for sound sources imitating a noisy machine or device. It is a continuation of experimental tests and modelling studies previously conducted on a prototype test stand, in which the enclosure walls measured 0.7 m × 0.7 m. The main aim of the current research was to estimate the acoustic efficiency of the enclosures through experimental testing on a new stand with walls measuring 0.55 m × 0.55 m, conducted under conditions similar to those found in an industrial facility. Tests conducted on five wall types of varying thicknesses, made of materials such as steel, aluminium, and plexiglass, enabled the development of a calculation model for insertion loss (IL), which can be used based on the material data for the enclosure walls. The model was validated through further experimental tests covering four additional material variants, and a high correlation of the results was obtained. The influence of the calculation model used for the enclosure wall transmission loss on the IL result was also investigated. The results of the experimental tests and modelling studies were also compared with those obtained for a larger enclosure made of the same wall materials. The research described in the current article may have practical applications in the selection of walls of cube-shaped enclosures and in estimating their effectiveness in a cost-free manner, assuming that appropriate material data are used in the calculations.
subject: Technical Notes
  topic: section
subject: acoustical enclosures
  topic: keywords
subject: insertion loss (IL)
  topic: keywords
subject: noise protection
  topic: keywords
creator: Krzysztof Kosała
rights: Copyright (c) 2026 Krzysztof Kosała https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 197
ending page: 209
doi: 10.24423/archacoust.2026.4316

Laboratory Evaluation of Underwater Acoustic Attenuation Provided by Air Bubble Curtains
type: item
description: Air bubble curtains are widely used in Chilean salmon farming to protect fish from water pollutants. Due to new requirements from the Environmental Assessment Service, their use for underwater noise mitigation has become very important. This study aimed to evaluate the acoustic attenuation provided by a type of curtain widely used in salmon farming and seawater desalination under laboratory conditions, obtaining results independent of the conditions encountered in field work. This allowed for comparative measurements of different bubble curtain configurations. This study presents the results of an acoustic evaluation of underwater sound attenuation provided by different bubble curtain configurations, conducted in the test channel of the Engineering Department at the Universidad Austral de Chile. The parameter evaluated was the insertion loss (IL). It was found that the evaluated bubble curtains provided a broadband insertion loss between 11 dB and 12 dB in the simplest configuration and IL per third-octave band equal to or greater than 10 dB. The 10 dB attenuation in the source level represents a significant reduction in the area of acoustic impact, reducing the physiological damage distances for the marine mammal species considered by at least 78.4 %.
subject: Technical Notes
  topic: section
subject: air-bubble curtain
  topic: keywords
subject: underwater sound attenuation
  topic: keywords
subject: reduction of physiological risk
  topic: keywords
subject: underwater noise control
  topic: keywords
subject: underwater acoustics
  topic: disciplines
creator: Alfio Yori
creator: Jose Luis Barros
creator: Rodrigo Torres
creator: Felipe Figueroa
rights: Copyright (c) 2026 Alfio Yori, Jose Luis Barros, Rodrigo Torres, Felipe Figueroa https://creativecommons.org/licenses/by/4.0
date: 2026-03-27
publication date: 2026-03-27
starting page: 161
ending page: 181
doi: 10.24423/archacoust.2026.4254

Simulation Analysis of Beam Intensity Attenuation Patterns and Source Depth Estimation Using a Vertical Long Line Array
type: item
description: In the deep-water reliable acoustic path (RAP), when estimating target depth using a vertical array, a large-aperture array can enhance the extraction of the acoustic field interference structure under low signal-to-noise ratio (SNR). However, this operation introduces slow envelope modulation (the envelope amplitude of peak beam intensity decreases with frequency) to the broadband acoustic field interference pattern, significantly degrading the performance of estimating the source depth. The Kraken normal-mode model can accurately calculate low-frequency sound fields in deep-water environments. This paper uses this tool to find that, in the deep-water direct arrival zone (DAZ), the peak beam intensity output of a vertical linear array varies across a broadband frequency range, exhibiting a pattern combining periodic changes of Lloyd’s mirror interference and inherent envelope attenuation changes. The physical mechanism of envelope attenuation is explained through both theoretical derivation and simulation analysis, key factors affecting the envelope-attenuation pattern are clarified, and the impact of beam-intensity envelope attenuation on the depth-estimation method based on matched beam intensity processing (MBIP) is pointed out. Based on this, a modified target depth estimation method of matched beam intensity processing (M-MBIP) that contains an attenuation coefficient is proposed, and its effectiveness is verified through simulated data.
subject: Research Papers
  topic: section
subject: deep-water direct arrival zone (DAZ)
  topic: keywords
subject: Lloyd’s mirror interference
  topic: keywords
subject: broadband attenuation pattern
  topic: keywords
subject: underwater acoustics
  topic: disciplines
creator: Hao WANG
creator: Guangying ZHENG
creator: Fangwei ZHU
creator: Xiaohong YANG
creator: Shuaishuai ZHANG
creator: Xiaowei GUO
rights: Copyright (c) 2025 Hao WANG, Guangying ZHENG, Fangwei ZHU, Xiaohong YANG, Shuaishuai ZHANG, Xiaowei GUO https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 501
ending page: 512
doi: 10.24425/aoa.2025.156931

Comparison of Methods for Determining the Airflow Resistivity of Porous and Covering Materials
type: item
description: This article compares two methods for determining the airflow resistivity of porous and coating materials – a key parameter in sound absorption modelling. The analysis involves a modified static airflow measurement procedure in accordance with International Organization for Standardization [ISO] (2018), using a linear approximation algorithm (PLA), and a reverse method consisting of matching the measured absorption coefficient in an impedance tube to the Miki model. The analysis was conducted on both porous materials utilised in acoustic panel fillings and thin coverings. It is evident that both methods yield analogous outcomes for materials exhibiting low resistivity. However, for materials characterised by higher resistivity, discrepancies of up to 50 % were observed. Nevertheless, a high degree of agreement was obtained between the calculated and measured absorption coefficients. For thin coating materials, an air gap of at least 70 mm is required. For materials with a thickness of up to approximately 30 mm, differences in resistivity do not significantly affect the absorption coefficient. It is evident that both methods can be used to determine the airflow resistivity of porous materials and layered structures, supporting the effective selection of materials according to requirements.
subject: Research Papers
  topic: section
subject: airflow resistivity
  topic: keywords
subject: specific airflow resistance
  topic: keywords
subject: sound absorption coefficient
  topic: keywords
subject: impedance tube
  topic: keywords
subject: porous materials
  topic: keywords
subject: other
  topic: disciplines
creator: Mykhaylo MELNYK
creator: Jarosław RUBACHA
creator: Artur FLACH
creator: Aleksandra CHOJAK
creator: Tadeusz KAMISIŃSKI
creator: Wojciech ZABIEROWSKI
creator: Marek IWANIEC
creator: Andryi KERNYTSKYY
rights: Copyright (c) 2025 Mykhaylo MELNYK, Jarosław RUBACHA, Artur FLACH, Aleksandra CHOJAK, Tadeusz KAMISIŃSKI, Wojciech ZABIEROWSKI, Marek IWANIEC, Andryi KERNYTSKYY https://creativecommons.org/licenses/by/4.0
date: 2025-11-25
publication date: 2025-11-25
starting page: 421
ending page: 433
doi: 10.24425/aoa.2025.154831