Special Issue "Room Acoustics"

A special issue of Acoustics (ISSN 2624-599X).

Deadline for manuscript submissions: 18 July 2022.

Special Issue Editor

Prof. Dr. Monika Rychtarikova
E-Mail Website
Guest Editor
1. Faculty of Architecture, KU Leuven, Hoogstraat 51, 9000 Gent/ Paleizenstraat 65, 1030 Brussels, Belgium
2. Faculty of Civil Engineering, Slovak University of Technology in Bratislava, Radlinsk¨¦ho 11, 810 05 Bratislava, Slovakia
Interests: building and room acoustics; environmental acoustics; virtual acoustics; perception of sound.
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Published Papers (8 papers)

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Article
Psychoacoustic Analysis of Vacuum Cleaner Noise
Acoustics 2021, 3(3), 545-558; https://doi.org/10.3390/acoustics3030035 - 04 Aug 2021
Viewed by 675
Abstract
Vacuum cleaners are one of the most widely used household appliances associated with unpleasant noises. Previous studies have indicated the severity of loud vacuum cleaner noise and its impact on the users nearby. The standalone quantified measurements of the generated noise are not [...] Read more.
Vacuum cleaners are one of the most widely used household appliances associated with unpleasant noises. Previous studies have indicated the severity of loud vacuum cleaner noise and its impact on the users nearby. The standalone quantified measurements of the generated noise are not sufficient for properly characterizing vacuum cleaners. Human perception should also be included for a better assessment of the quality of sound. A hybrid approach such as psychoacoustics analysis, which comprises subjective and objective evaluations of sounds, has recently been widely used. This paper focuses on the experimental assessment of vacuum cleaner noise and evaluates their psychoacoustical matrices. Three vacuum cleaners with different specifications have been selected as test candidates, and their sound qualities have been analyzed. Statistical analysis, ANOVA, has been performed in order to investigate the effectiveness of individual psychoacoustic metrics. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
The Difference in Subjective Experience Related to Acoustic Treatments in an Ordinary Public Room: A Case Study
Acoustics 2021, 3(2), 442-461; https://doi.org/10.3390/acoustics3020029 - 18 Jun 2021
Viewed by 1161
Abstract
In ordinary public rooms absorbent ceilings are normally used. However, reflective material such as diffusers can also be useful to improve the acoustic performance for this type of environment. In this study, different combinations of absorbers and diffusers have been used. The study [...] Read more.
In ordinary public rooms absorbent ceilings are normally used. However, reflective material such as diffusers can also be useful to improve the acoustic performance for this type of environment. In this study, different combinations of absorbers and diffusers have been used. The study investigates whether a test group of 29 people perceived sound in an ordinary room differently depending on the type of treatment. Comparisons of the same position in a room for different configurations as well as different positions within one configuration were made. The subjective judgements were compared to the room acoustic measures T20, C50 and G and the difference in the values of these parameters. It was found that when evaluating the different positions in a room, the configuration including diffusers was perceived to a greater extent as being similar in the different positions in the room when compared to the configuration with absorbers on the walls. It was also seen that C50 was the parameter that mainly affected the perception, with the difference needing to be 2 dB to recognize a difference. However, the room acoustic measurements could not fully explain the differences obtained in perception. In addition, the subjective sound image created by different types of treatments was also shown to have an important impact on the perception. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
Active Noise Control System Based on the Improved Equation Error Model
Acoustics 2021, 3(2), 354-363; https://doi.org/10.3390/acoustics3020024 - 31 May 2021
Cited by 2 | Viewed by 1203
Abstract
This paper presents an algorithm structure for an active noise control (ANC) system based on an improved equation error (EE) model that employs the offline secondary path modeling method. The noise of a compressor in a gas station is taken as an example [...] Read more.
This paper presents an algorithm structure for an active noise control (ANC) system based on an improved equation error (EE) model that employs the offline secondary path modeling method. The noise of a compressor in a gas station is taken as an example to verify the performance of the proposed ANC system. The results show that the proposed ANC system improves the noise reduction performance and convergence speed compared with other typical ANC systems. In particular, it achieves 28 dBA noise attenuation at a frequency of about 250 Hz and a mean square error (MSE) of about −20 dB. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
Pre-Sabine Room Acoustic Guidelines on Audience Rake, Stage Acoustics, and Dimension Ratios
Acoustics 2021, 3(2), 235-251; https://doi.org/10.3390/acoustics3020017 - 24 Mar 2021
Viewed by 1351
Abstract
Prior to Sabine’s work on the Fogg Art Museum and Boston Symphony Hall, several numerical guidelines had been developed and applied to the design of rooms with specific acoustic demands such as theatres, concert halls, and opera houses. Previous papers have discussed guidelines [...] Read more.
Prior to Sabine’s work on the Fogg Art Museum and Boston Symphony Hall, several numerical guidelines had been developed and applied to the design of rooms with specific acoustic demands such as theatres, concert halls, and opera houses. Previous papers have discussed guidelines based on the following principles: voice directivity, which was employed in the design of at least 11 rooms; “echo theory”, which quantifies the perception threshold between direct sound and first order reflections in order to prevent echoes from occurring, aiding in the design of at least 7 rooms and leading to the first known use of an acoustic scale model; and notions of reverberation, which influenced the design of at least 14 rooms. This paper discusses three additional pre-Sabine numerical guidelines that were used in room acoustic design: (1) audience rake, (2) stage acoustics and proscenium design, and (3) length, width, and height ratios. The origin of these theories, as well as examples of rooms in which they were applied, are discussed and compared to current practices in room acoustic design. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
Exposure to High-Frequency Sound and Ultrasound in Public Places: Examples from Zurich, Switzerland
Acoustics 2019, 1(4), 816-824; https://doi.org/10.3390/acoustics1040048 - 18 Oct 2019
Cited by 3 | Viewed by 2032
Abstract
The public is unknowingly exposed to very high-frequency sound (VHFS; 11.2–17.8 kHz) and ultrasound (US; >17.8 kHz) signals in air in public places, as evidenced by previously published reports. The present report provides evidence for the presence of VHFS/US signals in the air [...] Read more.
The public is unknowingly exposed to very high-frequency sound (VHFS; 11.2–17.8 kHz) and ultrasound (US; >17.8 kHz) signals in air in public places, as evidenced by previously published reports. The present report provides evidence for the presence of VHFS/US signals in the air at public places in Zurich, Switzerland. The analysis of the signals measured revealed that they: (i) contain one, two or multiple frequencies; (ii) comprise frequencies ranged from 15.5 kHz to 36.0 kHz; (iii) were either quasi constant in their amplitude or exhibit a clear amplitude modulation; and (iv) were in their characteristics (frequencies, modulation, intensity) specific for each place. Based on the signal characteristic it is likely that the signals are generated by public-address voice-alarm (PAVA) systems. The work presented: (i) documents the presence of VHFS/US signals at public places in Zurich, possibly caused by PAVA systems; and should (ii) show that is easily possibly to measure the signals with an affordable measurement equipment as a “citizen scientist”, and stimulate others also to measure and analyse VHFS/US signals with this citizen scientist approach in other cities worldwide. Due to the possible negative health-related effects of a human exposure to VHFS/US signals, further research is needed to document VHFS/US signals at public places and to evaluate biological effects of this exposure with laboratory studies. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
Influence of Sound-Absorbing Material Placement on Room Acoustical Parameters
Acoustics 2019, 1(3), 644-660; https://doi.org/10.3390/acoustics1030038 - 07 Aug 2019
Cited by 5 | Viewed by 3150
Abstract
The reverberation of a room is often controlled by installing sound absorption panels to the ceiling and on the walls. The reduced reverberation is particularly important in classrooms to maximize the speech intelligibility and in open-plan offices to make spaces more pleasant. In [...] Read more.
The reverberation of a room is often controlled by installing sound absorption panels to the ceiling and on the walls. The reduced reverberation is particularly important in classrooms to maximize the speech intelligibility and in open-plan offices to make spaces more pleasant. In this study, the impact of the placement of the absorption material in a room was measured in a reverberation room and in a mockup classroom. The results show that absorption material is less efficient if it is mounted to the corners or on the edges between the walls and ceiling, if the sound field is more or less diffuse. If the room modes dominate the sound field, the most efficient location for the sound-absorbing material was found at one of the surfaces causing the modes. The results help acoustical consultants to place the absorption material in optimal locations and, generally, minimize the amount of material and save costs. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
The Effects of Adding Pyramidal and Convex Diffusers on Room Acoustic Parameters in a Small Non-Diffuse Room
Acoustics 2019, 1(3), 618-643; https://doi.org/10.3390/acoustics1030037 - 02 Aug 2019
Cited by 2 | Viewed by 1531
Abstract
This paper presents an investigation of the effects of relatively large-scale pyramidal and convex-shaped diffusers on the acoustical properties of a small non-diffuse rectangular room. Room impulse responses (RIRs) were measured in various room configurations to extract the early decay time (EDT), reverberation [...] Read more.
This paper presents an investigation of the effects of relatively large-scale pyramidal and convex-shaped diffusers on the acoustical properties of a small non-diffuse rectangular room. Room impulse responses (RIRs) were measured in various room configurations to extract the early decay time (EDT), reverberation time (T20), early-to-late arriving sound ratio (C50), and clarity (C80). The difference between the parameters measured in the empty room were chosen to be the reference, and those measured in other room configurations was calculated. Statistical analysis of the measurement results supplements the investigation to determine whether the coverage and type of diffusers contribute significantly to the variation of the acoustical parameters. The results show that adding diffusers in the room generally decreases EDT as well as T20, and increases C50 as well as C80 for both diffuser types. The statistical analysis shows that the coverage of diffusers significantly contributes to the variation of the acoustical parameters in most conditions (octave band, diffuser type). The effect of the diffuser shape is only significant for some of the conditions (at 4 kHz, the number of diffusers). The data presented demonstrate that in a small non-diffuse room the reverberation can be controlled efficiently by redirecting the sound energy towards the most absorbing surfaces. Full article
(This article belongs to the Special Issue Room Acoustics)
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Article
An Expectation–Maximization-Based IVA Algorithm for Speech Source Separation Using Student’s t Mixture Model Based Source Priors
Acoustics 2019, 1(1), 117-136; https://doi.org/10.3390/acoustics1010009 - 10 Jan 2019
Cited by 1 | Viewed by 2034
Abstract
The performance of the independent vector analysis (IVA) algorithm depends on the choice of the source prior to better model the speech signals as it employs a multivariate source prior to retain the dependency between frequency bins of each source. Identical source priors [...] Read more.
The performance of the independent vector analysis (IVA) algorithm depends on the choice of the source prior to better model the speech signals as it employs a multivariate source prior to retain the dependency between frequency bins of each source. Identical source priors are frequently used for the IVA methods; however, different speech sources will generally have different statistical properties. In this work, instead of identical source priors, a novel Student’s t mixture model based source prior is introduced for the IVA algorithm that can adapt to the statistical properties of different speech sources and thereby enhance the separation performance of the IVA algorithm. The unknown parameters of the source prior and unmixing matrices are estimated together by deriving an efficient expectation maximization (EM) algorithm. Useful improvement in the separation performance in different realistic scenarios is confirmed by experimental studies on real datasets. Full article
(This article belongs to the Special Issue Room Acoustics)
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