Journal articles on the topic 'Acoustic noise'
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1
Arnold, Eliot. "Advancements in nanotechnology for acoustic management in pickleball." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A328. http://dx.doi.org/10.1121/10.0027695.
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This research investigates the use of advanced nano-fiber technology for sound and noise management in pickleball courts. The technology, known for its flexibility and adaptability, addresses the unique acoustic challenges of pickleball, a sport with a distinctive noise profile characterized by impulsive and unpredictable sounds. These nano-fibers are particularly effective in absorbing mid to high-frequency noises (800–5000 Hz) common in pickleball. Incorporating these nano-fibers into acoustic foams and textiles significantly enhances sound absorption, allowing for thinner materials while doubling performance compared to conventional materials. These fibers, about 1/500th the diameter of human hair, have a high surface area to volume ratio, aiding in sound scattering and increased friction with air molecules. This structure enables the efficient transformation of sound energy into heat, which is then effectively dissipated. Aligned with the Acoustical Society of America's standards, this abstract emphasizes a scientific breakthrough in sports acoustics, contributing to the reduction in urban noise pollution. The study underscores the impact of cutting-edge material technology in improving environmental acoustics and community well-being.
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Woolworth, David S. "Architectural acoustics: Buildings and beyond." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A28. http://dx.doi.org/10.1121/10.0026671.
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Architectural acoustics not only covers buildings and the environment around them but also human perception of the acoustic environment, indoors and outdoors. As a technical committee of the acoustical society, our members are spread over research, academia, practitioners and industry. Architectural acoustics is not reserved for concert halls and opera houses but applies to all occupied spaces and has a direct impact on quality of life of any user of the space. Specific topics within the discipline include but are not limited to environmental sound, speech privacy, and speech intelligibility, simulated acoustic environments, annoyance, human hearing, airborne and structureborne noise, sound and impact isolation, loudspeakers and microphones, room acoustics, soundscape, and acoustical measurements. The technical committee on noise is often a cosponsor of specials sessions by the TCAA, as noise control via architectural means is common practice. This presentation will provide an overview of the TCAA and the field of architectural acoustics and provide examples of current research and projects of interest.
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Kurra, Selma, and Ayca Sentop. "Interaction between annoyance, indoor noise levels and acoustic classification of buildings." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 1 (February 1, 2023): 6519–30. http://dx.doi.org/10.3397/in_2022_0980.
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Assessment of annoyance "at home" from environmental noises has been widely investigated so far and the ISO/TS 15666:2021 was developed to lead the socio-acoustic surveys. On the other hand, the rating of buildings' acoustical performance considering also the indoor noises, has been also well concerned in building acoustics and the studies have ended up with the ISO/TS 19488:2021 covering the acoustic classification system for buildings. Basically the rating system needs to be supported by the subjective tests in the field or in laboratories, to acquire data about the annoyance/disturbance or satisfaction of residents. If the target is to design the healthy, comfortable and sustainable acoustical environment, both technical standards might be harmonized in the future. In this paper, based on the dose/response relationships with respect to the indoor noise levels, an approach is proposed to translate the acoustic classes proposed in ISO/TS 19488, into the annoyance boundaries in terms of different scales (verbal/numerical and the HA% ) referred in ISO/TS 15666. The results from the previous laboratory and field studies conducted by the authors, have been used for verification of this approach.
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Lai, Heather L., Anne C. Balant, and Chih-Yang Tsai. "Machine learning for analysis of wind farm noise." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A278. http://dx.doi.org/10.1121/10.0027495.
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Two challenges associated with analyzing acoustical data from wind farms are: 1) separating turbine sounds from environmental sounds and 2) classifying acoustical samples into different types of wind turbine noise based on acoustic characteristics. Machine-learning methods for classifying general environmental sounds have been developed using large human classified databases (e.g., YAMNet), but only a few studies have targeted classification of wind farm noise (WFN) specifically. Techniques for classifying wind farm noise have focused on identification of amplitude modulation (AM) using both traditional methods such as low frequency peak prominence (IOA method) and machine learning methods using both targeted AM acoustics features and more general deep acoustic features. To address these two challenges, we are developing a multi-echelon machine learning framework to identify and classify noise from wind farms using publicly available windfarm data and open-source software. The first echelon provides an automated method for identifying WFN samples that are free of environmental sounds. The second echelon uses machine learning to classify these wind farm noises according to the degree of AM, prominent tones, and other factors that might contribute to the human response and are incorporated in the metrics used or potentially used to assess compliance with regulations.
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Wróbel, Jakub, and Damian Pietrusiak. "Noise Source Identification in Training Facilities and Gyms." Applied Sciences 12, no. 1 (December 22, 2021): 54. http://dx.doi.org/10.3390/app12010054.
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This paper deals with noise problems in industrial sites adapted for commercial training venues. The room acoustics of such an object were analyzed in the scope of the reverberation time and potential acoustic adaptation measures are indicated. Identification and classification of noise sources in training facilities and gyms was carried out based on the acoustic measurements. The influence of rubber padding on impact and noise reduction was investigated in the case of chosen noise-intensive exercise activities performed in a previously described acoustic environment. Potential noise reduction measures are proposed in the form of excitation reduction, vibration isolation, and room acoustics adaptation.
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Chai, Yuying, and Boya Yu. "Effect of rail traffic noises on the perception of the acoustic environment in office spaces." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, no. 6 (November 30, 2023): 2324–32. http://dx.doi.org/10.3397/in_2023_0342.
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This study conducted a laboratory experiment to investigate the effect of rail traffic noise on the perception of the acoustic environment in office spaces. The study considered two types of experiment stimuli, single noise, and combined noise. The single noise stimuli consisted of silence (SL), air conditioning noise (AC), irrelevant speech (SP), and six types of traffic noise (Tr). Traffic noise included road (R), maglev (Ma), tram (T), conventional train (C), high-speed train (H), and metro (Me). The combined noise stimuli used air conditioning sound and speech as background noise and combined with six types of traffic noise to form the experimental stimuli. Thirty subjects took part in laboratory experiments in which the acoustic environment was rated on two aspects: noise disturbance and acoustic comfort. Under single noises, the results showed that the noise source had a significant negative effect on the evaluation of the acoustic environment. The influence of traffic noises varied with the traffic type, which was lower and higher than that of irrelevant speech and air conditioning noise, respectively. Under combined acoustic conditions, acoustic comfort was affected by the main effects of background noise type, traffic noise type, and traffic noise level. In addition to the main effects, noise disturbance was also influenced by the interaction between traffic noise level and background noise type, and between traffic noise level and traffic noise type. Keywords: rail traffic noise; office space; acoustic environment; acoustic comfort; noise disturbance
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Ellison, Steve, Pierre Germain, and Roger Schwenke. "Making a room ready and ensuring success for active acoustics systems." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A169. http://dx.doi.org/10.1121/10.0023160.
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Active Acoustics systems can be thought of as reducing the effective absorption of a room and/or increasing its effective volume and depend upon well-designed acoustic treatment and room shaping. Because Active Acoustics systems cannot reduce HVAC noise or improve isolation, these associated acoustical properties depend on the room’s acoustical design. Therefore, a successful Active Acoustic system installation relies on coordination with the acoustical consultant, from conceptual design to scheduling initial rehearsals with the various performance groups that utilize the room. Installation examples from around the world, including Australasia, are provided to illustrate lessons learned for developing successful projects.
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Ishikawa, Kenji. "On the sensitivity and noise of acousto-optic sensing: Exploring the detection limits." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A260. http://dx.doi.org/10.1121/10.0027425.
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Acousto-optic sensing has garnered increasing attention in recent years due to its non-contact nature, gaining importance in a range of acoustic measurement applications. Although its potential is widely recognized, the signal-to-noise ratio often requires enhancement in practical applications, which can impede further development. While more sensitive measurement methods have been evolving, the discussion around noise and detection limits in acousto-optic sensing remains limited. This presentation will highlight the author's recent findings on sensitivity and noise in acousto-optic sensing. It aims to illuminate the achievable detection limits through a detailed analysis of optical and acoustic noises. The insights provided will offer a deeper understanding of the complexities involved and potentially guide future advancements in this field.
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Acosta, Oscar, Luis Hermida, Marcelo Herrera, Carlos Montenegro, Elvis Gaona, Mateo Bejarano, Kevin Gordillo, Ignacio Pavón, and Cesar Asensio. "Remote Binaural System (RBS) for Noise Acoustic Monitoring." Journal of Sensor and Actuator Networks 12, no. 4 (August 14, 2023): 63. http://dx.doi.org/10.3390/jsan12040063.
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The recent emergence of advanced information technologies such as cloud computing, artificial intelligence, and data science has improved and optimized various processes in acoustics with potential real-world applications. Noise monitoring tasks on large terrains can be captured using an array of sound level meters. However, current monitoring systems only rely on the knowledge of a singular measured value related to the acoustic energy of the captured signal, leaving aside spatial aspects that complement the perception of noise by the human being. This project presents a system that performs binaural measurements according to subjective human perception. The acoustic characterization in an anechoic chamber is presented, as well as acoustic indicators obtained in the field initially for a short period of time. The main contribution of this work is the construction of a binaural prototype that resembles the human head and which transmits and processes acoustical data on the cloud. The above allows noise level monitoring via binaural hearing rather than a singular capturing device. Likewise, it can be highlighted that the system allows for obtaining spatial acoustic indicators based on the interaural cross-correlation function (IACF), as well as detecting the location of the source on the azimuthal plane.
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Bergiadis, Willaim L. "Acoustic treatments for indoor and outdoor firing ranges." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A160. http://dx.doi.org/10.1121/10.0015883.
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Small-caliber firearms can produce impulse noises that frequently exceed 150 dB peak sound pressure level (dB pSPL) and can approach 185 dB pSPL. These impulse noises can present a significant risk for noise-induced hearing loss for the unprotected ear and pose a risk for persons wearing hearing protection that is possibly poorly fitted or insufficient. For range safety officers and personnel who work in the firing range on a regular basis, the daily cumulative effects of noise exposure can lead to increased fatigue and stress. Acoustic treatments of the reflective surfaces can mitigate these health risks. This paper will review some community noise guidelines as well as health and safety regulations. As a manufacturer of acoustic range treatments, the Troy System materials will be reviewed with regards to their laboratory performance and their capabilities to reduce noise in various firing ranges. One aspect of performance that may be overlooked is the safety features of the materials which Troy Acoustics provides, such as flammability, ability to be cleaned, and the resistance to moisture and mold.
11
Gee, Kent L., Micah Shepherd, Brian E. Anderson, Tracianne B. Neilsen, Matthew S. Allen, and Jonathan D. Blotter. "Graduate acoustics at Brigham Young University." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A253. http://dx.doi.org/10.1121/10.0027403.
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Graduate studies in acoustics at BYU prepare students for industry, research, and academia by complementing in-depth coursework with publishable research. Coursework provides students with a foundation in acoustical principles, practices and measurement skills, including a experimental techniques and technical writing. Labs across the curriculum cover calibration, directivity, scattering, absorption, laser Doppler vibrometry, experimental methods for dynamic structures, lumped-element mechanical systems, equivalent circuit modeling, arrays, filters, room acoustics, active noise control, and near-field acoustical holography. Recent thesis and dissertation topics include active noise control, directivity, room acoustics, energy-based acoustics, time reversal, nondestructive evaluation, vibration and acoustics of aerospace vehicles, biomedical applications, flow-based acoustics, voice production, aeroacoustics, sound propagation modeling, nonlinear propagation, high-amplitude noise analyses, machine and deep learning applied to ambient noise level prediction, crowd noise interpretation, and underwater acoustic source localization, and ocean environment classification. Graduate students are expected to present research at professional meetings and publish in peer-reviewed acoustics journals. Graduate students often serve as peer mentors to undergraduate students on related projects and may participate in field experiments to gain additional experience. @BYUAcoustics
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Ning, Ai Min, Cheng Li, and Zhao Liu. "Acoustic Transceiver Optimization Analysis for Downhole Sensor Data Telemetry via Drillstring." Applied Mechanics and Materials 302 (February 2013): 389–94. http://dx.doi.org/10.4028/www.scientific.net/amm.302.389.
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Downhole sensor data telemetry using acoustic waves along the drillstring helps to know the physical and chemical properties of the formation and drilling fluid in Logging While Drilling. However, complex drillstring channel characteristics and normal downhole drilling operations will often adversely affect the quality of acoustic telemetry. Based on a theoretical channel model, we analyze the effects of transceiver optimal placements on acoustic transmission through a periodic drillstring. Considering the downhole noisy conditions including the surface noise sources, the downhole noise sources and multiple reflection echoes, dual acoustic receivers and an acoustic isolator are analyzed to improve the Signal-to-Noise Ratio and the capacity of the uplink channel. By arranging two receivers spaced one-quarter wavelength apart at receiver ends, the suppression results of one-way downlink noises are evaluated with the aid of the channel transient simulation model. Then the isolating results of uplink noises from drilling bit are investigated, with regard to the isolator placed between the downhole transmitter and a noise source. These methods, in conjunction with the complex drillstring features, show that the uses of the available transceiver design and signal processing techniques can make the drillstring as a waveguide for transmitting downhole sensor information at high data rate.
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Kumar, Dileep, Dezhan Tu, Naifu Zhu, Dibo Hou, and Hongjian Zhang. "In-Line Acoustic Device Inspection of Leakage in Water Distribution Pipes Based on Wavelet and Neural Network." Journal of Sensors 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/5789510.
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Traditionally permanent acoustic sensors leak detection techniques have been proven to be very effective in water distribution pipes. However, these methods need long distance deployment and proper position of sensors and cannot be implemented on underground pipelines. An inline-inspection acoustic device is developed which consists of acoustic sensors. The device will travel by the flow of water through the pipes which record all noise events and detect small leaks. However, it records all the noise events regarding background noises, but the time domain noisy acoustic signal cannot manifest complete features such as the leak flow rate which does not distinguish the leak signal and environmental disturbance. This paper presents an algorithm structure with the modularity of wavelet and neural network, which combines the capability of wavelet transform analyzing leakage signals and classification capability of artificial neural networks. This study validates that the time domain is not evident to the complete features regarding noisy leak signals and significance of selection of mother wavelet to extract the noise event features in water distribution pipes. The simulation consequences have shown that an appropriate mother wavelet has been selected and localized to extract the features of the signal with leak noise and background noise, and by neural network implementation, the method improves the classification performance of extracted features.
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Jessen, Birger. "Measuring low noise level in dwellings." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 4 (February 1, 2023): 3978–86. http://dx.doi.org/10.3397/in_2022_0567.
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DS 490:2018 "Akustik - Lydklassifikation af boliger", translated to "Acoustics - Acoustic Classification of Dwellings" relates to many acoustical parameters, and two of them "Noise from ventilation" and "Reverberation times" are now being tested in real life in the Danish "Voluntary sustainability classification".(Called FBK) Danish building regulation state a sound level limit in dwellings from all kinds of technical systems at 30 dB(A), equal to the Acoustical class C, comparable with the limit in several countries. Research shows that 30 dB(A) does not ensure acoustic satisfying comfort for most people. The FBK have chosen to lower the noise limit to 25 dB(A), equal to acoustical class B. We need to improve the ventilation systems in order to reach such lower level of sound emission, and to be able to measure it implemented in dwellings. The paper describes some methods and in situ experience fighting background noise problems caused by activities around and in the dwelling, as well as in the measurement systems. Special analyses and editing of recordings based on listening and pragmatic judgements are relevant. The goal is: Measure and document low noise without a cost in time and money being a barrier for lower noise levels in dwellings.
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Le-Muet, Yoan, Patrick Chevret, Thomas Bonzom, and Laurent Brocolini. "Outlook for the ISO 22955: Acoustic quality of open plan offices." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 5 (February 1, 2023): 2633–42. http://dx.doi.org/10.3397/in_2022_0369.
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The ISO 22955 standard " Acoustic quality of open plan offices " was published in may 2021. It aims to provide principles, descriptors, and measurement methods to characterize acoustics, which are easy to use and correspond to the perception of the acoustical environment by the occupants of the spaces. The scope of the standard is the acoustics of open-plan offices and, more specifically, cognitive effects of noise, i.e. acoustic comfort and noise disturbance in association with the activity. After more than a year of use of the standard, this document proposes to take stock of it and to identify potential paths of reflection for a possible future revision. Among the points of discussion considered, are the consequences of the evolution of office work, activities and concepts in the tertiary sector (flex office, co-working, teleworking, etc.), and their implication on acoustic quality. Another fundamental matter is the relevance of the indicators used in the standard and the associated required values.
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Allen, Matthew S., Brian E. Anderson, Jonathan D. Blotter, Kent L. Gee, Tracianne B. Neilsen, Micah Shepherd, and Scott D. Sommerfeldt. "Graduate acoustics at Brigham Young University." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A122. http://dx.doi.org/10.1121/10.0015753.
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Graduate studies in acoustics at Brigham Young University prepare students for industry, research, and academia by complementing in-depth coursework with publishable research. Coursework provides a solid foundation in core acoustical principles and practices and measurement skills, including a strong foundation in experimental techniques and technical writing. Labs across the curriculum cover calibration, directivity, scattering, absorption, laser Doppler vibrometry, experimental methods for dynamic structures, lumped-element mechanical systems, equivalent circuit modeling, arrays, filters, room acoustics, active noise control, and near-field acoustical holography. Recent thesis and dissertation topics include active noise control, directivity, room acoustics, energy-based acoustics, time reversal, nondestructive evaluation, vibration and acoustics of aerospace vehicles, biomedical applications, flow-based acoustics, voice production, aeroacoustics, sound propagation modeling, nonlinear propagation, high-amplitude noise analyses, machine and deep learning applied to ambient noise level prediction, crowd noise interpretation, and underwater acoustic source localization, and ocean environment classification. Graduate students are expected to present research at professional meetings and publish in peer-reviewed acoustics journals. Additionally, graduate students often serve as peer mentors to undergraduate students on related projects and may participate in field experiments to gain additional experience.@BYUAcoustics
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Amran, M. Mohd, M. Shaiful Rizal, I. Maznan, Mohd Nazrul Roslan, Y. Musli Nizam, Mohd Imran Ghazali, and M. Shahruddin. "Evaluation of Sound Comfort in Examination Hall Using Acoustical Environmental Analyses." Applied Mechanics and Materials 315 (April 2013): 825–29. http://dx.doi.org/10.4028/www.scientific.net/amm.315.825.
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Acoustics environmental analyses were conducted in the unoccupied examination hall at Universiti Tun Hussein Onn Malaysia (UTHM), in order to determine the acoustical environment which reflects to sound comfort during sitting exam. The acoustic parameters that measured are background noise level, sound pressure level and reverberation time. The analysis result of untreated wall condition (without absorbent material) was revealed poor while treated wall condition (with absorbent material) revealed the improvement result. Installation of absorbent material on the wall and speakers rearrangement had reduced the highest background noise level of examination hall average reverberation times. A minor alteration at examination hall had contributed to better acoustic performance.
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Belsak, Ales, and Jurij Prezelj. "Acoustic Damage Analysis of a Gear System." Key Engineering Materials 488-489 (September 2011): 787–90. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.787.
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In diagnostics, noise can be a very reliable way of defining the condition of mechanical systems. There are different methods to visualise the noise source. Primarily, they deal with a specific noise source in a specific acoustic environment. This paper presents a visualization method of complex noise sources, using an acoustic camera. This method makes it possible to visualise all types of different complex noise sources; a special acoustic algorithm is applied for this purpose. Also, it is possible to observe various transient acoustical phenomena.
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Belsak, Ales, and Jurij Prezelj. "Investigating Sound Sources of Faulty Gear Units." Key Engineering Materials 417-418 (October 2009): 337–40. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.337.
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In diagnostics, the condition of mechanical systems can be determined very reliably on the basis of noise. Noise source visualization is based on a number of different methods. These methods are primarily intended for a specific noise source in a specific acoustic environment. In this paper, a visualization method of complex noise sources, based on the use of acoustic camera, is dealt with. All types of different complex noise sources can be visualized, using a special acoustic algorithm. Also, various transient acoustical phenomena can be observed.
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Mizumachi, Mitsunori, and Katsuyuki Niyada. "Robust Estimation of Sound Source Direction with Deterministic Background Noise and Stochastic Source Dynamics Models." Journal of Advanced Computational Intelligence and Intelligent Informatics 14, no. 2 (March 20, 2010): 208–13. http://dx.doi.org/10.20965/jaciii.2010.p0208.
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Direction of Arrival (DOA), a type of auxiliary information used in acoustic signal processing, is vulnerable to acoustical noise, so we want to male the estimation of DOA in noisy environments, relying on spectral sparseness. The energy of acoustic signals such as speech is wide-band, with individual signals localized in specific but different frequency regions. Our proposal involves filtering out spatial features provisionally from subband frequency components at the dominant frequency of the target signal using particle filtering with a sound source dynamics model. The feasibility of our proposal is confirmed by estimating a sound source direction in noisy conditions, also confirming that frequency selectivity and state estimation using particle filters help improve DOA estimation robustness against noise in noisy conditions.
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Reed, Veronica A., Cory A. Toth, Ryan N. Wardle, Dylan G. E. Gomes, Jesse R. Barber, and Clinton D. Francis. "Experimentally broadcast ocean surf and river noise alters birdsong." PeerJ 10 (May 17, 2022): e13297. http://dx.doi.org/10.7717/peerj.13297.
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Anthropogenic noise and its effects on acoustic communication have received considerable attention in recent decades. Yet, the natural acoustic environment’s influence on communication and its role in shaping acoustic signals remains unclear. We used large-scale playbacks of ocean surf in coastal areas and whitewater river noise in riparian areas to investigate how natural sounds influences song structure in six songbird species. We recorded individuals defending territories in a variety of acoustic conditions across 19 study sites in California and 18 sites in Idaho. Acoustic characteristics across the sites included naturally quiet ‘control’ sites, ‘positive control’ sites that were adjacent to the ocean or a whitewater river and thus were naturally noisy, ‘phantom’ playback sites that were exposed to continuous broadcast of low-frequency ocean surf or whitewater noise, and ‘shifted’ playback sites with continuous broadcast of ocean surf or whitewater noise shifted up in frequency. We predicted that spectral and temporal song structure would generally correlate with background sound amplitude and that signal features would differ across site types based on the spectral profile of the acoustic environment. We found that the ways in which song structure varied with background acoustics were quite variable from species to species. For instance, in Idaho both the frequency bandwidth and duration of lazuli bunting (Passerina amoena) and song sparrow (Melospiza melodia) songs decreased with elevated background noise, but these song features were unrelated to background noise in the warbling vireo (Vireo gilvus), which tended to increase both the minimum and maximum frequency of songs with background noise amplitude. In California, the bandwidth of the trill of white-crowned sparrow (Zonotrichia leucophrys) song decreased with background noise amplitude, matching results of previous studies involving both natural and anthropogenic noise. In contrast, wrentit (Chamaea fasciata) song bandwidth was positively related to the amplitude of background noise. Although responses were quite heterogeneous, song features of all six species varied with amplitude and/or frequency of background noise. Collectively, these results provide strong evidence that natural soundscapes have long influenced vocal behavior. More broadly, the evolved behavioral responses to the long-standing challenges presented by natural sources of noise likely explain the many responses observed for species communicating in difficult signal conditions presented by human-made noise.
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Lugli, Marco. "Toward a general model for the evolution of the auditory sensitivity under variable ambient noise conditions." Journal of the Acoustical Society of America 154, no. 4 (October 1, 2023): 2236–55. http://dx.doi.org/10.1121/10.0021306.
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Ambient noise constrains the evolution of acoustic signals and hearing. An earlier fitness model showed that the trade-off between sound detection and recognition helps predict the best level of auditory sensitivity for acoustic communication in noise. Here, the early model is improved to investigate the effects of different noise masking conditions and signal-to-noise ratios (SNRs). It is revealed that low sensitivity is expected for acoustic communication over short distances in complex noisy environments provided missed sound recognition is costly. By contrast, high sensitivity is expected for acoustic communication over long distances in quieter habitats or when sounds are received with good SNRs under unfavorable noise conditions. High sensitivity is also expected in noisy environments characterized by one dominant source of noise with a fairly constant spectrum (running-water noise) or when sounds are processed using anti-masking strategies favoring the detection and recognition of sound embedded in noise. These predictions help explain unexpected findings that do not fit with the current view on the effects of environmental selection on signal and sensitivity. Model predictions are compared with those of models of signal detection in noisy conditions and results of empirical studies.
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Mathews, Logan T., and Kent L. Gee. "Acoustic source characterization of shock-associated noise in an installed, full-scale F404 engine." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A63. http://dx.doi.org/10.1121/10.0026812.
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Shock-associated noise in supersonic jets is an important factor in acoustic radiation, particularly in the upstream direction. A previous paper [L. T. Mathews et al., J. Acoust. Soc. Am. 154, A325 (2023)] discussed a preliminary source characterization of shock-associated noise in a full-scale, installed tactical jet engine. Acoustical holography was used to reconstruct the acoustic behavior near the jet and high-amplitude features were produced that were consistent with shock-associated noise sources. This paper presents a more detailed characterization of shock-related noise in the jet using higher-fidelity methods, such as subarray processing and bandwidth extension. The spatial and spectral characteristics of the shock cell noise sources are discussed. A virtual reference decomposition method is used to examine the source and radiative characteristics of each detected shock noise source. The results are compared with shock noise characteristics in the literature. [Work supported by ONR Grant No. N00014-21-1-2069.]
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Tang, Shiu Keung, Mors Leung, Sherman S. L. Yip, and Rudolf Y. C. Lee. "On the acoustical protection of acoustic balconies." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, no. 2 (November 30, 2023): 6111–15. http://dx.doi.org/10.3397/in_2023_0899.
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Acoustic balcony is a recent development in Hong Kong for use as a noise screening device on high-rise building façades. It is in principle a balcony equipped with sound absorption materials (NRC 0.7) on its ceiling and side walls, as well as an inclined panel at its parapet. Windows are installed on the space above the parapet to block the direct noise intrusion path from outside to the indoor. In the present study, a full size balcony mockup is adopted in an open-air laboratory and the sound transmission loss of the balcony at different sound source orientations and elevations examined. A long linear loudspeaker array is used to mimic road traffic/ railway noise. The traffic/ railway noise transmission loss increases with source elevation under the effect of the inclined panel. For source elevation not larger than 45 deg, the difference between indoor and outdoor noise levels in the presence of the acoustic balcony with adjusted traffic noise spectrum varies from 10 dBA to 18 dBA while with adjusted railway noise spectrum varies from 11 dBA to 17 dBA.
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Kropotov, Y. A., A. A. Belov, and A. Y. Prockuryakov. "Increasing signal/acoustic interference ratio in telecommunications audio exchange by adaptive filtering methods." Information Technology and Nanotechnology, no. 2416 (2019): 271–76. http://dx.doi.org/10.18287/1613-0073-2019-2416-271-276.
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The paper deals with the issues of increasing signal/noise ratio in telecommunication audio exchange systems. The study of characteristics of speech signals and acoustic noises, such as mathematical expectation, dispersion, relative intensity of acoustic speech signals and various types of acoustic noises and interference is carried out. It is shown that in the design of telecommunications systems, in particular loudspeaker systems operating under the influence of external acoustic noise of high intensity, it is necessary to solve the problem of developing algorithms to effectively suppress the above mentioned interference to ensure the necessary signal/noise ratio in communication systems. A mathematical model of the autocorrelation function of the speech signal by using the Lagrange interpolation polynomial of order 10, considered the creation of adaptive algorithms to suppress acoustic noise by linear filtering methods. Thus suppression of acoustic noises and hindrances is possible at the expense of operated change of area of a cutting in the interval from 0 Hz to 300-1000 Hz, depending on a hindrance conditions.
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McCullah-Boozer, Megan R., Brooke M. Hinds, Logan T. Mathews, Mark C. Anderson, Michael Bassett, Lucas K. Hall, and Kent L. Gee. "A comparative analysis of rocket noise recordings from wildlife acoustic monitoring devices." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A72. http://dx.doi.org/10.1121/10.0018204.
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Remote acoustic recorders are used in wildlife passive acoustical monitoring (PAM) and species identification. Such devices are designed to be relatively low-cost, user-friendly, weather-robust, and operate for extended periods with low maintenance. Usually, the precision of these devices is limited because most applications do not require high-fidelity measurements for typical wildlife PAM applications. However, the relatively low cost and flexibility of deployment beg the question if they can accurately record other noise sources, such as rocket launches. Such a situation calls for an evaluation of accuracy and a complete understanding of their capabilities and limitations. As such documentation is limited, this study seeks to characterize the acoustic performance of two commercially available wildlife acoustic monitoring devices: the Wildlife Acoustics SM-4 and the Cornell Ornithology Laboratory SwiftOne. We present acoustical results from a laboratory experiment and a field measurement of an orbital rocket launch. Comparisons to industry standard devices are made in the time and frequency domains and show the spectral characteristics of these devices. Recommendations are made regarding the use of these devices based on their performance.
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Kim, Mintai, and Sungju Lee. "Power Transformer Voltages Classification with Acoustic Signal in Various Noisy Environments." Sensors 22, no. 3 (February 7, 2022): 1248. http://dx.doi.org/10.3390/s22031248.
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Checking the stable supply voltage of a power distribution transformer in operation is an important issue to prevent mechanical failure. The acoustic signal of the transformer contains sufficient information to analyze the transformer conditions. However, since transformers are often exposed to a variety of noise environments, acoustic signal-based methods should be designed to be robust against these various noises to provide high accuracy. In this study, we propose a method to classify the over-, normal-, and under-voltage levels supplied to the transformer using the acoustic signal of the transformer operating in various noise environments. The acoustic signal of the transformer was converted into a Mel Spectrogram (MS), and used to classify the voltage levels. The classification model was designed based on the U-Net encoder layers to extract and express the important features from the acoustic signal. The proposed approach was used for its robustness against both the known and unknown noise by using the noise rejection method with U-Net and the ensemble model with three datasets. In the experimental environments, the testbeds were constructed using an oil-immersed power distribution transformer with a capacity of 150 kVA. Based on the experimental results, we confirm that the proposed method can improve the classification accuracy of the voltage levels from 72 to 88 and to 94% (baseline to noise rejection and to noise rejection + ensemble), respectively, in various noisy environments.
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Oppenheimer, Charles. "Acoustic Dissipation and Modal Coupling in Server Computers." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 266, no. 2 (May 25, 2023): 203–13. http://dx.doi.org/10.3397/nc_2023_0030.
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Interest in the interior acoustics of server computers is growing as noise generated by air movers (fans) is increasingly observed to impact the performance of hard disk drives (HDD) inside these computers. In a typical server, a backplane cavity is located between an array of air movers and an array of HDD such that the HDD may be within a fan diameter of the air movers. The possibility of functional degradation requires careful management of air mover noise with respect to HDD susceptibility to acoustic noise disturbances and motivates understanding the physical phenomena underlying the acoustics. A previous investigation demonstrated the importance of coherence between acoustic standing wave modes in the backplane cavity. In this paper server interior airborne acoustics are further investigated by focusing on acoustic dissipation and inter-modal coupling in the backplane cavity. Various dissipation models are developed and used in conjunction with a previously formulated modal cavity acoustic model to generate cavity transfer factors. The transfer factor predictions are compared to measured transfer factors to draw further insights into the physical phenomena governing the interior cavity acoustics.
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Murad, Thamer Easa, and Yasin Yousif Al-Aboosi. "Statistical properties of underwater acoustic noise in Lake Hamrin, Diyala, Iraq." Indonesian Journal of Electrical Engineering and Computer Science 28, no. 1 (October 1, 2022): 192. http://dx.doi.org/10.11591/ijeecs.v28.i1.pp192-200.
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<p>The greatest challenge in underwater acoustic communication systems is the minimization of underwater impact noise. This article offers an empirical example for determining the statistical properties of underwater acoustic noise in the in Lake Hamrin. The data are measured from various depths reached in Lake Hamrin, Diyala, Iraq. In most communication systems, noise is assumed to be additive as well as Gaussian. Underwater acoustic noise (UWAN) isn't only thermal noise, it also includes other components to the UWAN: turbulence, wind and shipping noises. Thus, it should be assumed that the acoustic noise is colored noise instead of white noise. Intermittent noise in the oceans and seas frequently includes significant Non-Gaussian elements. The samples noise data are analyzed in actual time for various depths of 1 meter, 3 meter and 5 meter in order to limit the statistical properties of underwater acoustic noise in Lake Hamrin, Diyala, Iraq such as the autocorrelation function (ACF), the probability density function (PDF) and also power spectral density (PSD). The experimental results showed that the noise of the Tigris river is a color noise and does not follow the Gaussian distribution.</p>
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Hernandez, Gregory, Junfei Li, and Steven Cummer. "The acoustic metasphere. A solution to improving speech intelligibility and acoustic measurements." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A200. http://dx.doi.org/10.1121/10.0023260.
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The application of acoustic metamaterials has found utility in several disciplines ranging from biomedical ultrasound to architectural acoustics, and even the music industry. However, an underlying complication with these devices is their narrow bandwidth which limits the effectiveness of acoustic metamaterials in research and industry. Additionally, within architectural acoustics and noise control engineering, an issue that arises is speech intelligibility and clarity of the source. For example, within a populated and dense environment, such as an airport or shopping market, loudspeakers are placed every several feet to surmount the beaming directionality of these transducers at higher frequencies. Also, consequently, the gain must then be high enough to overcome this beaming effect and the noise floor generated by the environment and its occupants. Moreover, methods to more efficiently and cost effectively characterize the response of an acoustic space are needed to improve upon the noise control efforts within these locations. A solution to these obstacles is proposed with an acoustic metamaterial called the Acoustic Metasphere. Utilizing various twisting unit cells that fully envelop a loudspeaker, we demonstrate here that this acoustic metamaterial can improve the limitation of a loudspeaker due to its directionality, while simultaneously increasing the bandwidth of operation for this engineered structure.
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Fan, Feng, Yaxiong Cao, Lusheng Jiang, and Yongfeng Lin. "Research on Calculation Method for Acoustic Scattering of Helicopter Noise." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 38, no. 6 (December 2020): 1275–83. http://dx.doi.org/10.1051/jnwpu/20203861275.
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A new calculation method of helicopter rotor/fuselage acoustic scattering is developed. Firstly, a CFD analysis model is developed to simulate flow field of the rotor, which is based on the motional embedded grid system and RANS equations, and provides aerodynamic data for rotor noise calculation. Then, FW-H equations are employed to calculate the aeroacoustic characteristics of isolated rotor, and G 1A formulas are applied to calculate the rotor acoustic gradient to provide boundary condition for acoustic scattering. Based on these, the time-domain equivalent source method is applied to calculate acoustic scatter field, and the total acoustic field that considered the fuselage scatter is superposed by isolated rotor acoustics and the scatter one. Finally, the numerical simulations of helicopter main-rotor/fuselage and tail-rotor/fuselage scatter effect are conducted by using the developed models. The results indicate that the helicopter fuselage has important scatter effect on the high frequency acoustics of main rotor and tail rotor, and the acoustic scatter effect become more obvious with the smaller space between the main rotor (tail rotor) and fuselage.
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Putri, C. C., D. Hermawanto, and P. Prajitno. "Implementation of active noise cancelling for sound isolation box." Journal of Physics: Conference Series 2596, no. 1 (September 1, 2023): 012018. http://dx.doi.org/10.1088/1742-6596/2596/1/012018.
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Abstract A quiet room is essential for acoustical instrument calibration, such as the sound level meter. A small acoustic chamber can be utilized to create an environment that is free from noise. Commonly, it is built with a passive noise-blocking system using high-density absorber material such as rock wool or glass wool. However, this approach results in a room that is both heavy and costly. This paper proposes a mini acoustic chamber that utilizes an active noise cancelling (ANC) system to block the noise. A filtered-x least mean square (FxLMS) algorithm was implemented for the ANC system. A simulation of the system with the recorded actual noise data was conducted to find the optimum filter parameter. The results show that the ANC system could reduce the noise up to 2 dB for certain types of noises. The sound outside the chamber was recorded and processed offline to tune the filter parameter. Evaluation of the effectiveness of the proposed noise reduction system was performed by measuring the sound inside the chamber.
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Ang, Linus, Yong Koh, and Heow Lee. "Plate-Type Acoustic Metamaterials: Experimental Evaluation of a Modular Large-Scale Design for Low-Frequency Noise Control." Acoustics 1, no. 2 (April 1, 2019): 354–68. http://dx.doi.org/10.3390/acoustics1020019.
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For industrial applications, the scalability of a finalised design is an important factor to consider. The scaling process of typical membrane-type acoustic metamaterials may pose manufacturing challenges such as stress uniformity of the membrane and spatial consistency of the platelet. These challenges could be addressed by plate-type acoustic metamaterials with an internal tonraum resonator. By adopting the concept of modularity in a large-scale design (or meta-panel), the acoustical performance of different specimen configurations could be scaled and modularly combined. This study justifies the viability of two meta-panel configurations for low-frequency (80–500 Hz) noise control. The meta-panels were shown to be superior to two commercially available noise barriers at 80–500 Hz. This superiority was substantiated when the sound transmission class (STC) and the outdoor-indoor transmission class (OITC) were compared. The meta-panels were also shown to provide an average noise reduction of 22.7–27.4 dB at 80–400 Hz when evaluated in different noise environments—traffic noise, aircraft flyby noise, and construction noise. Consequently, the meta-panel may be further developed and optimised to obtain a design that is lightweight and yet has good acoustical performance at below 500 Hz, which is the frequency content of most problematic noises.
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Andargie, Maedot S., Marianne Touchie, and William O'Brien. "Subjective and objective evaluation of the impact and airborne sound insulation of multi-unit residential buildings." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 6 (August 1, 2021): 778–86. http://dx.doi.org/10.3397/in-2021-1648.
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Multi-unit residential building (MURB) occupants often express dissatisfaction with their suites' acoustic conditions despite existing building acoustic standards and regulations as well as growing research on noise control and building acoustics. Reasons for this include the lack of proper characterization of acoustic comfort in MURBs and lack of comprehensive and stringent regulations. To better understand factors that impact acoustic comfort and explore strategies to improve the acoustic performance of MURBs, investigations of acoustic conditions were carried out. This work presents the results of the investigations which include subjective and objective evaluations of acoustic conditions in two MURBs. Impact sound insulation measurements using both a tapping machine and a rubber ball as well as 24-hour indoor noise monitoring were carried out in unoccupied suites. An online survey was then used to collect subjective assessments of the noise conditions in the buildings and the effects on occupants' comfort post occupancy. Results of the data analysis suggest that occupants are more sensitive to low-frequency impact sounds than mid- and high-frequency impact noise.
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Spratford, Meredith, Elizabeth A. Walker, and Ryan W. McCreery. "Use of an Application to Verify Classroom Acoustic Recommendations for Children Who Are Hard of Hearing in a General Education Setting." American Journal of Audiology 28, no. 4 (December 16, 2019): 927–34. http://dx.doi.org/10.1044/2019_aja-19-0041.
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Purpose Classrooms including children who are hard of hearing (CHH) may be modified to manage noise and reverberation and improve speech perception. Little is known about the acoustic characteristics of contemporary general education classrooms that include CHH compared to classrooms of typical peers. We proposed the following research questions about the acoustic environment of general education classrooms including CHH: (a) How reliable are acoustic measurements collected using an iOS device, application, and external microphone? (b) What proportion of classrooms meet the American National Standards Institute's standards for unoccupied noise levels and reverberation? Method A smartphone application was used to measure sound levels, reverberation, and clarity for 164 general education classrooms including CHH. Linear mixed models were used to examine the following: (a) reliability of acoustic measures made using an application and external microphone and (b) predictors of sound levels, reverberation, and clarity for elementary classrooms including CHH. Results Results indicate the application reliably measures classroom acoustics. Classrooms exceeded the American National Standards Institute's recommended noise levels, but met reverberation time guidelines. Grade; heating, ventilation, and air conditioning status; and room volume predicted classroom acoustics. Conclusions As a screening tool, the application was shown to be effective in reliably measuring reverberation and classroom noise levels. The high levels of noise in unoccupied classrooms indicate a need for increased use of noise abatement strategies and the use of remote-microphone systems, especially in classrooms where noise levels cannot feasibly be reduced. Using an application may be a cost-effective method for monitoring important acoustic features that impact children's ability to understand speech in the classroom.
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Di, Guoqing, Yihang Wang, Yao Yao, Jiangang Ma, and Jian Wu. "Influencing Factors Identification and Prediction of Noise Annoyance—A Case Study on Substation Noise." International Journal of Environmental Research and Public Health 19, no. 14 (July 9, 2022): 8394. http://dx.doi.org/10.3390/ijerph19148394.
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Noise-induced annoyance is one person’s individual adverse reaction to noise. Noise annoyance is an important basis for determining the acceptability of environmental noise exposure and for formulating environmental noise standards. It is influenced by both acoustic and non-acoustic factors. To identify non-acoustic factors significantly influencing noise annoyance, 40 noise samples with a loudness level of 60–90 phon from 500–1000 kV substations were selected in this study. A total of 246 subjects were recruited randomly. Using the assessment scale of noise annoyance specified by ISO 15666-2021, listening tests were conducted. Meanwhile, basic information and noise sensitivity of each subject were obtained through a questionnaire and the Weinstein’s noise sensitivity scale. Based on the five non-acoustic indices which were identified in this study and had a significant influence on noise annoyance, a prediction model of annoyance from substation noise was proposed by a stepwise regression. Results showed that the influence weight of acoustic indices in the model accounted for 80% in which the equivalent continuous A-weighted sound pressure level and the sound pressure level above 1/1 octave band of 125 Hz were 65% and 15%, respectively. The influence weight of non-acoustic indices entering the model was 20% in which age, education level, noise sensitivity, income, and noisy degree in the workplace were 8%, 2%, 4%, 4%, and 2%, respectively. The result of this study can provide a basis for factors identification and prediction of noise annoyance.
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Shao, Jianwang, Tao Zeng, and Xian Wu. "Study of a Nonlinear Membrane Absorber Applied to 3D Acoustic Cavity for Low Frequency Broadband Noise Control." Materials 12, no. 7 (April 8, 2019): 1138. http://dx.doi.org/10.3390/ma12071138.
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As a new approach to passive noise control in low frequency domain, the targeted energy transfer (TET) technique has been applied to the 3D fields of acoustics. The nonlinear membrane absorber based on the TET can reduce the low frequency noise inside the 3D acoustic cavity. The TET phenomenon inside the 3D acoustic cavity has firstly investigated by a two degrees-of-freedom (DOF) system, which is comprised by an acoustic mode and a nonlinear membrane without the pre-stress. In order to control the low frequency broadband noise inside 3D acoustic cavity and consider the influence of the pre-stress for the TET, a general model of the system with several acoustic modes of 3D acoustic cavity and one nonlinear membrane is built and studied in this paper. By using the harmonic balance method and the numerical method, the nonlinear normal modes and the forced responses are analyzed. Meanwhile, the influence of the pre-stress of the nonlinear membrane for the TET is investigated. The desired working zones of the nonlinear membrane absorber for the broadband noise are investigated. It can be helpful to design the nonlinear membrane according the dimension of 3D acoustic cavity to control the low frequency broadband noise.
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Cheng, Li, Chang Jinfeng, Liu Zhao, Fan Shangchun, and Ding Tianhuai. "Characteristics Analysis of Joint Acoustic Echo and Noise Suppression in Periodic Drillstring Waveguide." Shock and Vibration 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/741314.
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A new method of wireless data telemetry used by oil industry uses compressional acoustic waves to transmit downhole information from the bottom hole to the surface. Unfortunately, acoustic echoes and drilling vibration noises in periodic drillstring are a major issue in transmission performance. A combined acoustic echo and noise suppression method based on wave motion characteristic in drillstring is adopted to enhance an upward-going transmitted acoustic signal. The presented scheme consists of a primary acoustic echo canceller using an array of two accelerometers for dealing with the downward-going noises and a secondary acoustic insulation structure for restraining the upward-going vibration noises. Furthermore, the secondary acoustic insulation structure exhibits a banded and dispersive spectral structure because of periodic groove configuration. By using a finite-differential algorithm for the one-dimensional propagation of longitudinal waves, acoustic receiving characteristics of transmitted signals are simulated with additive Gaussian noise in a periodic pipe structure of limited length to investigate the effects on transmission performance optimization. The results reveal that the proposed scheme can achieve a much lower error bit ratio over a specified acoustic isolation frequency range with a 30–40 dB reduction in the average noise level compared to traditional single-receiver scheme.
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SONI, AR SHAILJA. "Exploring the Therapeutic Potential of Acoustic Interventions in Healing Environments." INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, no. 04 (April 4, 2024): 1–5. http://dx.doi.org/10.55041/ijsrem30024.
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High noise levels in hospitals pose risks to both patients and staff, inducing stress, discomfort, and restlessness. This study presents results from a noise survey conducted in a Dhaka teaching hospital, revealing daytime levels ranging from 48 to 63 dB LAeq, exceeding Bangladesh standards. Noise levels correlated with ward layout and sources, not patient demographics. Strategies such as noise reduction, acoustic materials, and staff/patient programs can improve hospital acoustics effectively. This study reviews research from multiple disciplines including medicine, psychology, architecture, and acoustics, focusing on topics such as hospital noise, sleep quality, patient privacy, and music therapy. Findings indicate hospitals often exceed recommended noise levels, negatively impacting patients and staff with sleep problems, higher blood pressure, and burnout. Poorly designed sound environments compromise patient privacy and communication. Strategies like private rooms, sound-absorbing materials, and music therapy are recommended to reduce noise levels and improve communication. To enhance patient confidentiality, private rooms with sound-blocking features are suggested. Overall, the study underscores the importance of sound management in healthcare and advocates for design strategies to mitigate noise-related issues while ensuring effective communication. KEY WORDS: Noise, patient, acoustic, healthcare, hospital.
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Godin, Oleg A., and Kay L. Gemba. "Graduate programs in physical, engineering, and underwater acoustics at the Naval Postgraduate School." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A122. http://dx.doi.org/10.1121/10.0015752.
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The Departments of Physics and of Electrical and Computer Engineering at the Naval Postgraduate School offer graduate programs in acoustics leading to MS and PhD degrees in applied physics and engineering acoustics. Engineering acoustics degrees can be completed in either traditional or distance learning modes. The departments also offer stand-alone academic certificate programs in fundamentals of engineering acoustics, underwater acoustics, and sonar system applications, with a set of three certificates leading to a MS degree in engineering acoustics. MS and PhD programs are interdisciplinary, with courses and laboratory work drawn principally from the fields of physics and electrical engineering. Subjects covered include waves and oscillations; fundamentals of physical and structural acoustics; the generation, propagation, and reception of sound in the ocean; civilian and military applications of sonar systems; and acoustic signal processing. Topics of recent theses and dissertations include development and field testing of novel sensors for atmospheric and ocean acoustics, modeling and measurements of ambient noise and sound propagation in the ocean, sound scattering in underwater waveguides, acoustic vector sensors and vector field properties, acoustic communications, noise interferometry, time reversal in acoustics, geo-acoustic inversion, acoustic remote sensing of the ocean, and acoustics of autonomous underwater and aerial vehicles.
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Han, Yang, Hong Zhou, Meng Yi Shi, and Chang Jin. "Acoustic Optimization for Intake System of Commercial Bus." Applied Mechanics and Materials 635-637 (September 2014): 334–40. http://dx.doi.org/10.4028/www.scientific.net/amm.635-637.334.
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Based on simulation and test, a method for engine acoustical source characteristic extraction and acoustic optimization was presented. The intake noise of engine of commercial bus with four different acoustical loads was measured and the characteristic of the noise was extracted using the four-load method. The values of intake noise calculated by BEM were compared with the values measured in the vehicle intake noise test. The comparison result showed that the simulation values agreed with the experimental ones at most of the range which indicated that the extracted result was reliable. The anechoic frequency was determined by analyzing the intake noise spectrum measured in the vehicle intake noise test. Finally, an effective scheme adding a Helmholtz resonator and a quarter wave tube was proposed by simulation, applied to the real vehicle and verified in the test. The acoustic performance of the intake system was improved significantly.
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Gaudette, Jason E., and James A. Simmons. "Linear time-invariant (LTI) modeling for aerial and underwater acoustics." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A95. http://dx.doi.org/10.1121/10.0018285.
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Most newcomers to acoustic signal processing understand that linear time-invariant (LTI) filters can remove out-of-band noise from time series signals. What many acoustics researchers may not realize is that LTI models can be applied much more broadly, including to non-linear and time-variant systems. This presentation covers an overview of the autoregressive (AR), moving-average (MA), and autoregressive moving-average (ARMA) family of LTI models and their many useful applications in acoustics. Examples include analytic time-frequency processing of multi-component echolocation signals, fractional-delay filtering for acoustic time series simulations, broadband acoustic array beamforming, adaptive filtering for noise cancelation, and system identification for acoustic equalizers (i.e., flattening the frequency response of a source-receiver pair). This talk serves as a brief tutorial and inspiration for researchers who want to expand their use of signal processing, especially those in the fields of animal bioacoustics, aerial acoustics, and underwater acoustics.
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Yu, Boya, Yuying Chai, and Chao Wang. "Effect of the Exterior Traffic Noises on the Sound Environment Evaluation in Office Spaces with Different Interior Noise Conditions." Applied Sciences 14, no. 7 (April 3, 2024): 3017. http://dx.doi.org/10.3390/app14073017.
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The present study focuses on the impact of exterior traffic noises on sound environment evaluation in office spaces, considering their interaction with interior noises. There were three interior noise conditions: silence, air-conditioner noise, and irrelevant speech noise. Six exterior traffic noises (road, maglev, tram, metro, conventional inter-city train, and high-speed train) were merged with interior noise clips to create the combined noise stimuli. Forty subjects participated in the experiment to assess the acoustic environment in office spaces exposed to multiple noises. The results showed that both interior and exterior noise significantly affected acoustic comfort and noise disturbance. As for the exterior traffic noise, both the traffic noise source and the noise level were found to be influential on both attributes. More temporally fluctuating traffic noises, such as high-speed train noise, were found to have a greater negative effect on subjective evaluations. Meanwhile, the interior noise source was also found to influence evaluations of the sound environment. Compared to the single traffic noise condition, irrelevant speech noise significantly increased the negative impact of traffic noises, while the air-conditioner noise had a neutral effect. In addition, participants in offices with speech noise were less sensitive to the traffic noise level.
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Ahamed, Bulbul, Rasel Ahmed, Khaled Mahmud, and Mohammad Nurul Huda. "Robust Phoneme Recognizer at Noise Corrupted Acoustic Environment." Scholars Journal of Engineering and Technology 4, no. 7 (July 2016): 308–11. http://dx.doi.org/10.21276/sjet.2016.4.7.3.
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Kumar, Sanjay, and Heow Lee. "The Present and Future Role of Acoustic Metamaterials for Architectural and Urban Noise Mitigations." Acoustics 1, no. 3 (August 1, 2019): 590–607. http://dx.doi.org/10.3390/acoustics1030035.
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Owing to a steep rise in urban population, there has been a continuous growth in construction of buildings, public or private transport like cars, motorbikes, trains, and planes at a global level. Hence, urban noise has become a major issue affecting the health and quality of human life. In the current environmental scenario, architectural acoustics has been directed towards controlling and manipulating sound waves at a desired level. Structural engineers and designers are moving towards green technologies, which may help improve the overall comfort level of residents. A variety of conventional sound absorbing materials are being used to reduce noise, but attenuation of low-frequency noise still remains a challenge. Recently, acoustic metamaterials that enable low-frequency sound manipulation, mitigation, and control have been widely used for architectural acoustics and traffic noise mitigation. This review article provides an overview of the role of acoustic metamaterials for architectural acoustics and road noise mitigation applications. The current challenges and prominent future directions in the field are also highlighted.
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Smith-Dalenberg, Holly, Christopher S. Allen, and Jose G. Limardo-Rodriguez. "The challenges and successes of passive acoustic treatments on the International Space Station." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 4 (August 1, 2021): 2393–404. http://dx.doi.org/10.3397/in-2021-2126.
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Habitable space environments pose unique challenges to the selection of passive acoustic treatments used to mitigate noise. On the International Space Station, strict regulations regarding flammability, particulate release, and off-gassing must be considered during material selection, resulting in the exclusion of many common acoustic treatments used in ground-based applications. The Johnson Space Center Acoustics Office has identified a small subset of acoustic absorption and barrier materials that meet these stringent requirements, and has developed numerous treatments for noise mitigation, including duct-wrapping and liners, acoustic absorption and barrier blankets, and mufflers. The Acoustics Office utilizes impedance and transmission loss tubes to optimize the layering of acoustic materials for these treatments while observing restrictive volume and mass limits. Future acoustic mitigation development will focus on moisture and microbial-resistant materials and treatments that can be utilized in enclosed spaces that require higher scrutiny in regards to cleanliness, such as waste management bays and surfaces surrounding exercise equipment or galleys.
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Greenwood, Eric, and Robert Rau. "A Maneuvering Flight Noise Model for Helicopter Mission Planning." Journal of the American Helicopter Society 65, no. 2 (April 1, 2020): 1–10. http://dx.doi.org/10.4050/jahs.65.022007.
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A new model for estimating the noise radiation during maneuvering flight is developed in this paper. The model applies the quasi-static acoustic mapping (Q-SAM) method to a database of acoustic spheres generated using the fundamental rotorcraft acoustics modeling from experiments (FRAME) technique. A method is developed to generate a realistic flight trajectory from a limited set of waypoints and is used to calculate the quasi-static operating condition and corresponding acoustic sphere for the vehicle throughout the maneuver. By using a previously computed database of acoustic spheres, the acoustic impact of proposed helicopter operations can be rapidly predicted for use in mission planning. The resulting FRAME-QS model is applied to near-horizon noise measurements collected for the Bell 430 helicopter undergoing transient pitch-up and roll maneuvers, with good agreement between the measured data and the FRAME-QS model.
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Liang, Ping, Hongyu Guan, Yuezhen Wang, Han Chen, Pengfei Song, Haonan Ma, and Songtao Hu. "The Effect of Music Tempo and Volume on Acoustic Perceptions under the Noise Environment." Sustainability 13, no. 7 (April 6, 2021): 4055. http://dx.doi.org/10.3390/su13074055.
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This study aimed to investigate the distracting or masking effects of music tempo and volume, based on subjective evaluation under noise conditions. Two experiments were conducted with 32 participants. In the first one, the experimental conditions were set as follow: (1) the sound pressure levels of music are 45 dB, 60 dB, and 75 dB; (2) music tempos are 70 beats per minute (BPM), 110 BPM, and 150 BPM; (3) sound pressure levels of noise are 45 dB, 60 dB, and 75 dB; and (4) the noise types are talkers’ babble, traffic noise, and construction noise. All conditions on human acoustic perception were analyzed by orthogonal experiment. Based on part one, the second experiment was conducted. Sound pressure levels (50 dB, 60 dB, and 70 dB) of noise and sound pressure levels (50 dB, 60 dB, and 70 dB) of music and music tempo (70 BPM, 110 BPM, and 150 BPM) were assessed by subjective evaluation. The results showed although different types of noise had different effects on human perceptions, noise types had a small effect on acoustic comfort considering the superimposed music. Music can improve the acoustic environment. The sound pressure levels had significant effects on acoustic sensation. The tempo of the music affected the acoustic sensation insignificantly. Sound pressure levels of noise, music tempo, and sound pressure levels of music significantly affect acoustic comfort. The best acoustic environment in this study utilized superimposed 70 BPM, 60 dB music in a 50 dB noise environment. These results suggest that music can enable new strategies to improve indoor environmental satisfaction. Based on the findings, the effect of music on acoustic perceptions under the noise environment should be taken into account when aiming to enhance comfort in noisy environments.
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Grafe, T. Ulmar, and Joremy A. Tony. "Temporal variation in acoustic and visual signalling as a function of stream background noise in the Bornean foot-flagging frog, Staurois parvus." Journal of Ecoacoustics 1, no. 1 (October 26, 2017): 1. http://dx.doi.org/10.22261/jea.x74qe0.
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High background noise can interfere with signal detection and perception. Bornean foot-flagging frogs,Staurois parvus, live along noisy streams and use both acoustic and visual signals to communicate. It remains unclear why acoustic signalling is retained given that visual signalling appears to have clear advantages under these noisy conditions. We hypothesized that temporal dynamics in stream noise have shaped the multimodal communication system inS. parvuswith acoustic signalling at an advantage under more quiet conditions, whereas visual signals will prevail when the noise of rushing water is high after rains. We found that as predicted, maleS. parvusincreased foot flagging and decreased advertisement calling when presented with playbacks of stream noise compared to less noisy pre-playback conditions. Such context-dependent dynamic-selection regimes are recently gaining wider attention and enhance our understanding of the flexibility seen in the use of multimodal signals inS. parvus.
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Sun, Qindong, and Hongkun Zhou. "An Acoustic Sea Glider for Deep-Sea Noise Profiling Using an Acoustic Vector Sensor." Polish Maritime Research 29, no. 1 (March 1, 2022): 57–62. http://dx.doi.org/10.2478/pomr-2022-0006.
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Abstract An acoustic sea glider has been developed for ambient sea noise measurement and target detection through the deployment of an acoustic vector sensor (AVS). The glider was designed with three cabins connected in sequence and it can dive to depths exceeding 1200m. The AVS fixed on the glider measure acoustic pressure and particle velocities related to undersea noise, and the inner attitude sensors can effectively eliminate the estimation deviation of the direction of arrival. The inherent self-noises of the acoustic sea glider and AVS are presented respectively in respect to the Knudsen spectra of sea noise. Sea trial results indicate that the AVS could work well for undersea noise measurement when the glider is smooth sliding, and the target azimuth estimated by AVS after correction is remarkably consistent with the values measured by the GPS, and direction-finding errors are less than 10 degrees. The research in this paper shows that the acoustic sea glider is able to undertake tasks such as a wide range of underwater acoustic measurement and detection.