Acoustics

Research

19 pages, 2647 KiB

Open AccessArticle

Study and Improvement of Acoustic Conditions in Public Spaces of Shopping Malls

by Nikolay Kanev

Acoustics 2021, 3(1), 137-155; https://doi.org/10.3390/acoustics3010011 - 22 Feb 2021

Cited by 5 | Viewed by 5924

Acoustic comfort in shopping malls is one of the aspects that influence the shopping environment. Making enjoyable and comfortable retail and public spaces is demanded when designing and managing properties. This paper focuses on the study of the public spaces with a large [...] Read more.

Acoustic comfort in shopping malls is one of the aspects that influence the shopping environment. Making enjoyable and comfortable retail and public spaces is demanded when designing and managing properties. This paper focuses on the study of the public spaces with a large volume in the operating malls, which are perceived as acoustically uncomfortable. The main reason for poor acoustic conditions is a too long reverberation, as the measured reverberation time reached 4–5 s at middle frequencies. The usual way to improve the acoustics is to apply sound-absorbing materials on space surfaces. Two examples of improving acoustic conditions in food courts are given. In both cases, the reverberation time was reduced by about half, and changes in acoustics were considered significant and positive. It is shown the Sabine’s equation is valid for considered spaces. Average absorption coefficients are found by means of the Sabine’s equation and can be used for quick estimation of the reverberation time in similar spaces without the absorbing treatment. Based on the analysis of this and other studies, a method for qualitative assessment of the public space acoustics is proposed. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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16 pages, 1743 KiB

Open AccessArticle

Audio Feedback for Device-Supported Balance Training: Parameter Mapping and Influencing Factors

by Dominik Fuchs, Martin Knauer, Marion Egger and Petra Friedrich

Acoustics 2020, 2(3), 650-665; https://doi.org/10.3390/acoustics2030034 - 29 Aug 2020

Cited by 2 | Viewed by 4492

Abstract

Recent studies suggest that real-time auditory feedback is an effective method to facilitate motor learning. The evaluation of the parameter mapping (sound-to-movement mapping) is a crucial, yet frequently neglected step in the development of audio feedback. We therefore conducted two experiments to evaluate [...] Read more.

Recent studies suggest that real-time auditory feedback is an effective method to facilitate motor learning. The evaluation of the parameter mapping (sound-to-movement mapping) is a crucial, yet frequently neglected step in the development of audio feedback. We therefore conducted two experiments to evaluate audio parameters with target finding exercises designed for balance training. In the first experiment with ten participants, five different audio parameters were evaluated on the X-axis (mediolateral movement). Following that, in a larger experiment with twenty participants in a two-dimensional plane (mediolateral and anterior-posterior movement), a basic and synthetic audio model was compared to a more complex audio model with musical characteristics. Participants were able to orient themselves and find the targets with the audio models. In the one-dimensional condition of experiment one, percussion sounds and synthetic sound wavering were the overall most effective audio parameters. In experiment two, the synthetic model was more effective and better evaluated by the participants. In general, basic sounds were more helpful than complex (musical) sound models. Musical abilities and age were correlated with certain exercise scores. Audio feedback is a promising approach for balance training and should be evaluated with patients. Preliminary evaluation of the respective parameter mapping is highly advisable. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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13 pages, 2776 KiB

Open AccessArticle

An Extension of the Virtual Rotating Array Method Using Arbitrary Microphone Configurations for the Localization of Rotating Sound Sources

by Simon Jekosch and Ennes Sarradj

Acoustics 2020, 2(2), 330-342; https://doi.org/10.3390/acoustics2020019 - 15 May 2020

Cited by 17 | Viewed by 3836

Abstract

The characterization of rotating aeroacoustic sources using microphone array methods has been proven to be a useful tool. One technique to identify rotating sources is the virtual rotating array method. The method interpolates the pressure time data signals between the microphones in a [...] Read more.

The characterization of rotating aeroacoustic sources using microphone array methods has been proven to be a useful tool. One technique to identify rotating sources is the virtual rotating array method. The method interpolates the pressure time data signals between the microphones in a stationary array to compensate the motion of the rotating sources. One major drawback of the method is the requirement of ring array geometries that are centred around the rotating axis. This contribution extends the virtual rotating array method to arbitrary microphone configurations. Two different ways to interpolate the time signals between the microphone locations are proposed. The first method constructs a mesh between the microphone positions using Delaunay-triangulation and interpolates over the mesh faces using piecewise linear functions. The second one is a meshless technique which is based on radial basis function interpolation. The methods are tested on synthetic array data from a benchmark test case as well as on experimental data obtained with a spiral array and a five-bladed fan. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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23 pages, 7269 KiB

Open AccessArticle

Computer Modeling of Barrel-Vaulted Sanctuary Exhibiting Flutter Echo with Comparison to Measurements

by Heather Lai and Brian Hamilton

Acoustics 2020, 2(1), 87-109; https://doi.org/10.3390/acoustics2010007 - 17 Feb 2020

Cited by 11 | Viewed by 4856

Abstract

Computer modeling in acoustics allows for the prediction of acoustical defects and the evaluation of potential remediations. In this article, computer modeling is applied to the case of a barrel-vaulted sanctuary whose architectural design and construction led to severe flutter echoes along the [...] Read more.

Computer modeling in acoustics allows for the prediction of acoustical defects and the evaluation of potential remediations. In this article, computer modeling is applied to the case of a barrel-vaulted sanctuary whose architectural design and construction led to severe flutter echoes along the main aisle, which was later mitigated through acoustical remediations. State-of-the-art geometrical acoustics and wave-based simulations are carried out to analyze the acoustics of this space, with a particular focus on the flutter echoes along the main aisle, before and after remediations. Multi-resolution wavelet and spectrogram analyses are carried out to isolate and characterize flutter echoes within measurements and computer-simulated room impulse responses. Comparisons of simulated responses to measurements are also made in terms of decay times and curves. Simulated room impulse responses from both geometrical acoustics and wave-based methods show evidence of flutter echoes matching measurements, to varying degrees. Time-frequency analyses isolating flutter echoes demonstrate better matches to measurements from wave-based simulated responses, at the cost of longer simulation times than geometrical acoustics simulations. This case study highlights the importance of computer modeling of acoustics in early design phases of architectural planning of worship spaces. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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14 pages, 5344 KiB

Open AccessArticle

Cyclists′ Exposure to Road Traffic Noise: A Comparison of Three North American and European Cities

by Philippe Apparicio and Jérémy Gelb

Acoustics 2020, 2(1), 73-86; https://doi.org/10.3390/acoustics2010006 - 17 Feb 2020

Cited by 12 | Viewed by 7119

Abstract

According to the World Health Organization, high levels of exposure to road traffic noise are associated with adverse health effects. Earlier studies suggest that cyclists are exposed to higher noise levels than motorists. Other studies have demonstrated that cyclists’ exposure to noise could [...] Read more.

According to the World Health Organization, high levels of exposure to road traffic noise are associated with adverse health effects. Earlier studies suggest that cyclists are exposed to higher noise levels than motorists. Other studies have demonstrated that cyclists’ exposure to noise could vary significantly according to their routes. The aim of this study is to compare cyclists’ exposure to noise and their determinants in three cities. Three participants cycled equipped with noise dosimeters and GPS watches: 1823, 967, and 1362 km in Copenhagen, Paris, and Montreal, respectively. We fitted three generalized additive mixed model with an autoregressive term models to predict the cyclists’ exposure to noise according to the type of route and bicycle infrastructure after controlling for the day of the week, as well as spatial and temporal trends. The overall noise means were 73.4, 70.7, and 68.4 dB(A) in Paris, Montreal, and Copenhagen, respectively. The exposure to road traffic noise is strongly associated with the type of bicycle infrastructure taken by the cyclist; riding on a cycleway significantly decreases it, while riding in a shared lane has no impact. Our findings demonstrate that it is possible to achieve a substantial reduction in cyclists′ exposure by adopting new practices that include noise exposure in the planning of future cycling infrastructure. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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19 pages, 2102 KiB

Open AccessArticle

Comparing Turkish and European Noise Management and Soundscape Policies: A Proposal of Indoor Soundscape Integration to Architectural Design and Application

by Uğur Beyza ERÇAKMAK and Papatya Nur DÖKMECİ YÖRÜKOĞLU

Acoustics 2019, 1(4), 847-865; https://doi.org/10.3390/acoustics1040051 - 8 Nov 2019

Cited by 19 | Viewed by 5237

Abstract

Improving soundscape studies and policies states that the soundscape approach, which also considers noise interventions, should replace noise management. However, a considerable number of soundscape studies have been concerned with the quality of acoustic environments of open and urban public spaces. This study [...] Read more.

Improving soundscape studies and policies states that the soundscape approach, which also considers noise interventions, should replace noise management. However, a considerable number of soundscape studies have been concerned with the quality of acoustic environments of open and urban public spaces. This study focuses on indoor soundscaping and its possible integration into the architectural design and application process. Therefore, the present and ongoing Turkish and European soundscape and noise management policies were evaluated in detail and compared in order to characterize the gap regarding the state of indoor soundscaping between the literature and the policy development level. Furthermore, we identified and classified factors and methods which have an influence on indoor soundscaping to be integrated into the final proposed model. As a result of the detailed evaluation regarding policies and indoor soundscaping principles, five stages were proposed that can be used in an integrated indoor soundscape model: (1) the establishment of a topic specific institution or working group on indoor soundscaping; (2) the preparation of a standard that includes definitions, indoor soundscape factors and methods; (3) the preparation of an indoor soundscape directive; (4) the preparation of indoor soundscape guidelines; and (5) the provision of maintenance and supervision by experts and authorities. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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20 pages, 3400 KiB

Open AccessArticle

Commissioning the Acoustical Performance of an Open Office Space Following the Latest Healthy Building Standard: A Case Study

by Amy Kim, Shuoqi Wang, Lindsay McCunn, Aleksejs Prozuments, Troy Swanson and Kim Lokan

Acoustics 2019, 1(3), 473-492; https://doi.org/10.3390/acoustics1030027 - 9 Jul 2019

Cited by 11 | Viewed by 7623

Abstract

Healthy building design guides are cogent and necessary. While elements that contribute to healthy buildings are multifactorial, the perception of sound versus noise is subjective and difficult to operationalize. To inform the commissioning process, the acoustics in an open office was examined following [...] Read more.

Healthy building design guides are cogent and necessary. While elements that contribute to healthy buildings are multifactorial, the perception of sound versus noise is subjective and difficult to operationalize. To inform the commissioning process, the acoustics in an open office was examined following the first international building certification system that focuses on the well-being of occupants. Results highlight the role facility managers play in ensuring acoustical quality and offer suggestions to optimize healthy building rating systems. Mixed empirical evidence concerning the advantages of open office designs exists, as does evidence that noise, and a lack of privacy, affects workers’ levels of distraction and dissatisfaction. Sound masking systems can lower stress levels and augment performance. However, the sound produced by these systems can also be disruptive; conflicting information exists for facility managers to use when making decisions. The results suggest that, although objective measurements and healthy building guidelines for designing satisfactory indoor acoustic environments are important, changes to the physical environment, and acoustical systems, in particular, require iterative subjective assessments within the retrofit process to bolster occupant satisfaction. Mixed-methodologies used in this study may aid facilities managers in capturing and interpreting occupant data about physical stimuli in the workplace and improving the commissioning process. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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13 pages, 553 KiB

Open AccessArticle

An Enhanced Temporal Feature Integration Method for Environmental Sound Recognition

by Vasileios Bountourakis, Lazaros Vrysis, Konstantinos Konstantoudakis and Nikolaos Vryzas

Acoustics 2019, 1(2), 410-422; https://doi.org/10.3390/acoustics1020023 - 8 May 2019

Cited by 23 | Viewed by 4276

Abstract

Temporal feature integration refers to a set of strategies attempting to capture the information conveyed in the temporal evolution of the signal. It has been extensively applied in the context of semantic audio showing performance improvements against the standard frame-based audio classification methods. [...] Read more.

Temporal feature integration refers to a set of strategies attempting to capture the information conveyed in the temporal evolution of the signal. It has been extensively applied in the context of semantic audio showing performance improvements against the standard frame-based audio classification methods. This paper investigates the potential of an enhanced temporal feature integration method to classify environmental sounds. The proposed method utilizes newly introduced integration functions that capture the texture window shape in combination with standard functions like mean and standard deviation in a classification scheme of 10 environmental sound classes. The results obtained from three classification algorithms exhibit an increase in recognition accuracy against a standard temporal integration with simple statistics, which reveals the discriminative ability of the new metrics. Full article

(This article belongs to the Special Issue Indoor Soundscape: Integrating Sound, Experience and Architecture)

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