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5 pages, 204 KiB

Open AccessEditorial

Special Issue: Advances in Architectural Acoustics

by Nikolaos M. Papadakis, Massimo Garai and Georgios E. Stavroulakis

Appl. Sci. 2022, 12(3), 1728; https://doi.org/10.3390/app12031728 - 08 Feb 2022

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Abstract

Satisfactory acoustics is crucial for the ability of spaces such as auditoriums and lecture rooms to perform their primary function [...] Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

Research

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10 pages, 2403 KiB

Open AccessArticle

Mechanism Analysis of the Influence of Seat Attributes on the Seat Dip Effect in Music Halls

by Hequn Min and Yitian Liao

Appl. Sci. 2021, 11(20), 9768; https://doi.org/10.3390/app11209768 - 19 Oct 2021

Cited by 2 | Viewed by 1633

Abstract

The seat dip effect (SDE) is an acoustic phenomenon of low-frequency band attenuation that occurs in the music halls when the sound of the music passes at a near grazing incidence over the seats. In this paper, the numerical simulations on the basis [...] Read more.

The seat dip effect (SDE) is an acoustic phenomenon of low-frequency band attenuation that occurs in the music halls when the sound of the music passes at a near grazing incidence over the seats. In this paper, the numerical simulations on the basis of the finite element method are conducted to study the influence of seat attributes (seat height, seat spacing and seat absorption) on the SDE and the corresponding mechanism. The mapping of sound spatial distribution related to the SDE is employed to observe the behavior of sound between the seats. The results show that the dip frequency of the SDE can be shifted to frequencies lower than theoretical values when the seat height is smaller than the seat spacing. Additionally, the SDE attenuation can be distinctly suppressed in a sequence from the front seats to the rear seats with an absorption improvement to the seat back or cushion, and the seat back absorption is more effective than the cushion absorption. A mechanism analysis reveals that the SDE is highly associated with standing waves inside the seat gaps and with the “diffusion” effect on the grazing incident waves by energy flow vortexes around the top surfaces of the seats. Full article

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13 pages, 1318 KiB

Open AccessArticle

On the Sequence of Unmasked Reflections in Shoebox Concert Halls

by Juan Óscar García Gómez, Oliver Wright, Elisabeth van den Braak, Javier Sanz, Liam Kemp and Thomas Hulland

Appl. Sci. 2021, 11(17), 7798; https://doi.org/10.3390/app11177798 - 25 Aug 2021

Cited by 2 | Viewed by 2191

Abstract

Highly appreciated concert halls have their own acoustic signature. These signatures may not often be consciously appraised by general audiences, but they have a significant impact on the appreciation of the hall. Previous research indicates that two of the most important defining elements [...] Read more.

Highly appreciated concert halls have their own acoustic signature. These signatures may not often be consciously appraised by general audiences, but they have a significant impact on the appreciation of the hall. Previous research indicates that two of the most important defining elements of a hall’s acoustic signature are (i) the reflection sequence and relative reflection levels at the listener position and (ii) the perceptibility of the reflections based on perception thresholds. Early research from Sir Harold Marshall identified the importance of unmasked early reflections to enhance a concert hall’s acoustic signature. The authors see an opportunity to extend the existing research by further examining the sequence of unmasked reflections. By analysing the cross-sections of three concert halls, this manuscript quantifies potential links between a hall’s architectural form, the resultant skeletal reflections, and the properties of its acoustic signature. While doing so, the manuscript identifies potential masking reflections through visual and analytical assessment of a hall’s skeletal reflections. It is hypothesized that the “rhythm” of the reflection sequence could hold key insights into the hall’s “personality” and acoustic signature. If so, this could present new design tools and considerations for new concert halls and the diagnosis of underperformance in existing halls. Full article

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16 pages, 3800 KiB

Open AccessArticle

Power Response and Modal Decay Estimation of Room Reflections from Spherical Microphone Array Measurements Using Eigenbeam Spatial Correlation Model

by Amy Bastine, Thushara D. Abhayapala and Jihui (Aimee) Zhang

Appl. Sci. 2021, 11(16), 7688; https://doi.org/10.3390/app11167688 - 21 Aug 2021

Cited by 3 | Viewed by 1774

Abstract

Modal decays and modal power distribution in acoustic environments are key factors in deciding the perceptual quality and performance accuracy of audio applications. This paper presents the application of the eigenbeam spatial correlation method in estimating the time-frequency-dependent directional reflection powers and modal [...] Read more.

Modal decays and modal power distribution in acoustic environments are key factors in deciding the perceptual quality and performance accuracy of audio applications. This paper presents the application of the eigenbeam spatial correlation method in estimating the time-frequency-dependent directional reflection powers and modal decay times. The experimental results evaluate the application of the proposed technique for two rooms with distinct environments using their room impulse response (RIR) measurements recorded by a spherical microphone array. The paper discusses the classical concepts behind room mode distribution and the reasons behind their complex behavior in real environments. The time-frequency spectrum of room reflections, the dominant reflection locations, and the directional decay rates emulate a realistic response with respect to the theoretical expectations. The experimental observations prove that our model is a promising tool in characterizing early and late reflections, which will be beneficial in controlling the perceptual factors of room acoustics. Full article

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11 pages, 1392 KiB

Open AccessArticle

Coherent Image Source Modeling of Sound Fields in Long Spaces with a Sound-Absorbing Ceiling

by Hequn Min and Ke Xu

Appl. Sci. 2021, 11(15), 6743; https://doi.org/10.3390/app11156743 - 22 Jul 2021

Cited by 3 | Viewed by 1495

Abstract

Sound-absorbing boundaries can attenuate noise propagation in practical long spaces, but fast and accurate sound field modeling in this situation is still difficult. This paper presents a coherent image source model for simple yet accurate prediction of the sound field in long enclosures [...] Read more.

Sound-absorbing boundaries can attenuate noise propagation in practical long spaces, but fast and accurate sound field modeling in this situation is still difficult. This paper presents a coherent image source model for simple yet accurate prediction of the sound field in long enclosures with a sound absorbing ceiling. In the proposed model, the reflections on the absorbent boundary are separated from those on reflective ones during evaluating reflection coefficients. The model is compared with the classic wave theory, an existing coherent image source model and a scale-model experiment. The results show that the proposed model provides remarkable accuracy advantage over the existing models yet is fast for sound prediction in long spaces. Full article

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27 pages, 24868 KiB

Open AccessArticle

An Energy Model for the Calculation of Room Acoustic Parameters in Rectangular Rooms with Absorbent Ceilings

by Erling Nilsson and Emma Arvidsson

Appl. Sci. 2021, 11(14), 6607; https://doi.org/10.3390/app11146607 - 18 Jul 2021

Cited by 5 | Viewed by 2283

Abstract

The most common acoustical treatment of public rooms, such as schools, offices, and healthcare premises, is a suspended absorbent ceiling. The non-uniform distribution of the absorbent material, as well as the influence of sound-scattering objects such as furniture or other interior equipment, has [...] Read more.

The most common acoustical treatment of public rooms, such as schools, offices, and healthcare premises, is a suspended absorbent ceiling. The non-uniform distribution of the absorbent material, as well as the influence of sound-scattering objects such as furniture or other interior equipment, has to be taken into account when calculating room acoustic parameters. This requires additional information than what is already inherent in the statistical absorption coefficients and equivalent absorption areas provided by the reverberation chamber method ISO 354. Furthermore, the classical diffuse field assumption cannot be expected to be valid in these types of rooms. The non-isotropic sound field has to be considered. In this paper, a statistical energy analysis (SEA) model is derived. The sound field is subdivided into a grazing and non-grazing part where the grazing part refers to waves propagating almost parallel to the suspended ceiling. For estimation of all the inherent parameters in the model, the surface impedance of the suspended ceiling has to be known. A method for estimating the scattering and absorbing effects of furniture and objects is suggested in this paper. The room acoustical parameters reverberation time

T_{20}

, speech clarity

C_{50}

, and sound strength

G

were calculated with the model and compared with calculations according to the classical diffuse field model. Comparison with measurements were performed for a classroom configuration. With regard to all cases, the new model agrees better with measurements than the classical one. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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10 pages, 1358 KiB

Open AccessArticle

Comfort Distance—A Single-Number Quantity Describing Spatial Attenuation in Open-Plan Offices

by Valtteri Hongisto and Jukka Keränen

Appl. Sci. 2021, 11(10), 4596; https://doi.org/10.3390/app11104596 - 18 May 2021

Cited by 9 | Viewed by 2451

Abstract

ISO 3382-3 is globally used to determine the room acoustic conditions of open-plan offices using in situ measurements. The key outcomes of the standard are three single-number quantities: distraction distance, r_D, A-weighted sound pressure level of speech, L_p,A,S,4m, and [...] Read more.

ISO 3382-3 is globally used to determine the room acoustic conditions of open-plan offices using in situ measurements. The key outcomes of the standard are three single-number quantities: distraction distance, r_D, A-weighted sound pressure level of speech, L_p,A,S,4m, and spatial decay rate of speech, D_2,S. Quantities L_p,A,S,4m and D_2,S describe the attenuation properties of the office due to room and furniture absorption and geometry. Our purpose is to introduce a new single-number quantity, comfort distance r_C, which integrates the quantities L_p,A,S,4m and D_2,S. It describes the distance from an omnidirectional loudspeaker where the A-weighted sound pressure level of normal speech falls below 45 dB. The study explains why the comfort criterion level is set to 45 dB, explores the comfort distances in 185 offices reported in previous studies. Based on published data, the r_C values lie typically within 3 m (strong attenuation) and 30 m (weak attenuation). Based on this data, a classification scheme was proposed. The new quantity could benefit the revised version of ISO 3382-3. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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20 pages, 24601 KiB

Open AccessFeature PaperArticle

A Trial Acoustic Improvement in a Lecture Hall with MPP Sound Absorbers and FDTD Acoustic Simulations

by Matteo Cingolani, Giulia Fratoni, Luca Barbaresi, Dario D’Orazio, Brian Hamilton and Massimo Garai

Appl. Sci. 2021, 11(6), 2445; https://doi.org/10.3390/app11062445 - 10 Mar 2021

Cited by 12 | Viewed by 3674

Abstract

Sound absorbing micro-perforated panels (MPPs) are being increasingly used because of their high quality in terms of hygiene, sustainability and durability. The present work investigates the feasibility and the performance of MPPs when used as an acoustic treatment in lecture rooms. With this [...] Read more.

Sound absorbing micro-perforated panels (MPPs) are being increasingly used because of their high quality in terms of hygiene, sustainability and durability. The present work investigates the feasibility and the performance of MPPs when used as an acoustic treatment in lecture rooms. With this purpose, three different micro-perforated steel specimens were first designed following existing predictive models and then physically manufactured through 3D additive metal printing. The specimens’ acoustic behavior was analyzed with experimental measurements in single-layer and double-layer configurations. Then, the investigation was focused on the application of double-layer MPPs to the ceiling of an existing university lecture hall to enhance speech intelligibility. Numerical simulations were carried out using a full-spectrum wave-based method: a finite-difference time-domain (FDTD) code was chosen to better handle time-dependent signals as the verbal communication. The present work proposes a workflow to explore the suitability of a specific material to speech requirements. The measured specific impedance complex values allowed to derive the input data referred to MPPs in FDTD simulations. The outcomes of the process show the influence of the acoustic treatment in terms of reverberation time (

T_{30}

) and sound clarity (

C_{50}

). A systematic comparison with a standard geometrical acoustic (GA) technique is reported as well. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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25 pages, 6093 KiB

Open AccessArticle

Historically Based Room Acoustic Analysis and Auralization of a Church in the 1470s

by Hanna Autio, Mathias Barbagallo, Carolina Ask, Delphine Bard Hagberg, Eva Lindqvist Sandgren and Karin Strinnholm Lagergren

Appl. Sci. 2021, 11(4), 1586; https://doi.org/10.3390/app11041586 - 10 Feb 2021

Cited by 8 | Viewed by 3365

Abstract

Worship space acoustics have been established as an important part of a nation’s cultural heritage and area of acoustic research, but more research is needed regarding the region of northern Europe. This paper describes the historical acoustics of an important abbey church in [...] Read more.

Worship space acoustics have been established as an important part of a nation’s cultural heritage and area of acoustic research, but more research is needed regarding the region of northern Europe. This paper describes the historical acoustics of an important abbey church in Sweden in the 1470s. A digital historical reconstruction is developed. Liturgical material specific to this location is recorded and auralized within the digital reconstruction, and a room acoustic analysis is performed. The analysis is guided by liturgical practices in the church and the monastic order connected to it. It is found that the historical sound field in the church is characterized by the existence of two distinct acoustical subspaces within it, each corresponding to a location dedicated to the daily services of the monastical congregations. The subspaces show significantly better acoustic conditions for liturgical activities compared to the nave, which is very reverberant under the conditions of daily services. Acoustic transmission from the two subspaces is limited, indicating that the monastic congregations were visually and acoustically separated from the visitors in the nave and each other. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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19 pages, 6225 KiB

Open AccessArticle

Evolutionary Analysis of the Acoustics of the Baroque Church of San Luis de los Franceses (Seville)

by Enedina Alberdi, Miguel Galindo and Ángel L. León-Rodríguez

Appl. Sci. 2021, 11(4), 1402; https://doi.org/10.3390/app11041402 - 04 Feb 2021

Cited by 7 | Viewed by 2100

Abstract

In the 16th century the Society of Jesus built a large number of churches following the Tridentine model of a Latin cross and a single nave. However, the shift towards this model did not entail the abandonment of the central floor plan, especially [...] Read more.

In the 16th century the Society of Jesus built a large number of churches following the Tridentine model of a Latin cross and a single nave. However, the shift towards this model did not entail the abandonment of the central floor plan, especially in the 17th century. The acoustics of these spaces can present phenomena linked to focalizations which increase the sound pressure level. The church of San Luis de los Franceses, built by the Jesuits for their novitiate in Seville (Spain), is an example of a Baroque church with a central floor plan. Although the church has hosted different congregations since its inauguration it is currently desacralized and used for theatres and concerts. The acoustics of this church were studied by the authors through in situ measurements and virtual models. The main objective was to analyse the evolution and perception of its sound field from the 18th to 21st centuries, considering the different audience distributions and sound sources and the modifications in furniture and coatings. Analysis of the evolution of its sound field shows that the characteristics have remained stable, with a notable influence of the dome on the results for the different configurations studied. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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22 pages, 5225 KiB

Open AccessArticle

A Machine Learning Based Prediction Model for the Sound Absorption Coefficient of Micro-Expanded Metal Mesh (MEMM)

by Yaw-Shyan TSAY and Chiu-Yu YEH

Appl. Sci. 2020, 10(21), 7612; https://doi.org/10.3390/app10217612 - 28 Oct 2020

Cited by 3 | Viewed by 2336

Abstract

Recently, micro-perforated panels (MPP) have become a popular sound absorbing material in the field of architectural acoustics. However, the cost of MPP is still high for the commercial market in Taiwan, and MPP is still not very popular compared to other sound absorbing [...] Read more.

Recently, micro-perforated panels (MPP) have become a popular sound absorbing material in the field of architectural acoustics. However, the cost of MPP is still high for the commercial market in Taiwan, and MPP is still not very popular compared to other sound absorbing materials and devices. The objective of this study is to develop a prediction model for MEMM via a machine learning approach. An experiment including 14 types of MEMM was first carried out in a reverberation room based on ISO 354. To predict the sound absorption coefficient of the MEMM, the capability of three conventional models and three machine learning (ML) models of the supervised learning method were studied for the development of the prediction model. The results showed that in most conventional models, the sound absorption coefficient of using an equivalent perimeter had the best agreement compared with other parameters, and the root mean square error (RMSE) between prediction models and experimental data were around 0.2~0.3. However, the RMSE of all ML models was less than 0.1, and the RMSE of the gradient boost model was 0.033 in the training sets and 0.062 in the testing sets, which showed the best agreement with the experiment data. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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18 pages, 3308 KiB

Open AccessArticle

Measurements of Acoustical Parameters in the Ancient Open-Air Theatre of Tyndaris (Sicily, Italy)

by Arianna Astolfi, Elena Bo, Francesco Aletta and Louena Shtrepi

Appl. Sci. 2020, 10(16), 5680; https://doi.org/10.3390/app10165680 - 15 Aug 2020

Cited by 17 | Viewed by 3513

Abstract

The emerging field of archaeoacoustics is attracting increasing research attention from scholars of different disciplines: the investigation of the acoustic features of ancient open-air theatres is possibly one of its main themes. In this paper, the outcomes of a measurement campaign of acoustical [...] Read more.

The emerging field of archaeoacoustics is attracting increasing research attention from scholars of different disciplines: the investigation of the acoustic features of ancient open-air theatres is possibly one of its main themes. In this paper, the outcomes of a measurement campaign of acoustical parameters in accordance with ISO 3382-1 in the ancient theatre of Tyndaris (Sicily) are presented and compared with datasets from other sites. Two sound sources were used (firecrackers and dodecahedron) and their differences were analysed. A very good reproducibility has been shown between the two measurement chains, with differences on average of 0.01 s for reverberation time T₂₀, and less than 0.3 dB for Clarity C₅₀ and C₈₀ and for sound strength. In general, results show that the reverberation time and strength of sound values are relatively low when compared with other theatres because of the lack of the original architectural element of the scaenae frons. When combining this effect with the obvious condition of an unroofed space, issues emerge in terms of applicability of the protocols recommended in the ISO standard. This raises the question of whether different room acoustics parameters should be used to characterise open-air ancient theatres. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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24 pages, 4975 KiB

Open AccessArticle

Listeners Sensitivity to Different Locations of Diffusive Surfaces in Performance Spaces: The Case of a Shoebox Concert Hall

by Louena Shtrepi, Sonja Di Blasio and Arianna Astolfi

Appl. Sci. 2020, 10(12), 4370; https://doi.org/10.3390/app10124370 - 25 Jun 2020

Cited by 8 | Viewed by 2351

Abstract

Diffusive surfaces are considered as one of the most challenging aspects to deal with in the acoustic design of concert halls. However, the acoustic effects that these surface locations have on the objective acoustic parameters and on sound perception have not yet been [...] Read more.

Diffusive surfaces are considered as one of the most challenging aspects to deal with in the acoustic design of concert halls. However, the acoustic effects that these surface locations have on the objective acoustic parameters and on sound perception have not yet been fully understood. Therefore, the effects of these surfaces on the acoustic design parameters have been investigated in a real shoebox concert hall with variable acoustics (Espace de Projection, IRCAM, Paris, France). Acoustic measurements have been carried out in six hall configurations by varying the location of the diffusive surfaces over the front, mid, and rear part of the lateral walls, while the other surfaces have been maintained absorptive or reflective. Moreover, two reference conditions, that is, fully absorptive and reflective boundaries of the hall have been tested. Measurements have been carried out at different positions in the hall, using an artificial head and an array of omnidirectional microphones. Conventional ISO 3382 objective acoustic parameters have been evaluated in all conditions. The results showed that the values of these parameters do not vary significantly with the diffusive surface location. Moreover, a subjective investigation performed by using the ABX method with auralizations at two listening positions revealed that listeners are not sensitive to the diffusive surface location variations even when front-rear asymmetric conditions are compared. However, some of them reported perceived differences relying on reverberance, coloration, and spaciousness. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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24 pages, 5980 KiB

Open AccessArticle

Time Domain Room Acoustic Solver with Fourth-Order Explicit FEM Using Modified Time Integration

by Takumi Yoshida, Takeshi Okuzono and Kimihiro Sakagami

Appl. Sci. 2020, 10(11), 3750; https://doi.org/10.3390/app10113750 - 28 May 2020

Cited by 11 | Viewed by 2688

Abstract

This paper presents a proposal of a time domain room acoustic solver using novel fourth-order accurate explicit time domain finite element method (TD-FEM), with demonstration of its applicability for practical room acoustic problems. Although time domain wave acoustic methods have been extremely attractive [...] Read more.

This paper presents a proposal of a time domain room acoustic solver using novel fourth-order accurate explicit time domain finite element method (TD-FEM), with demonstration of its applicability for practical room acoustic problems. Although time domain wave acoustic methods have been extremely attractive in recent years as room acoustic design tools, a computationally efficient solver is demanded to reduce their overly large computational costs for practical applications. Earlier, the authors proposed an efficient room acoustic solver using explicit TD-FEM having fourth-order accuracy in both space and time using low-order discretization techniques. Nevertheless, this conventional method only achieves fourth-order accuracy in time when using only square or cubic elements. That achievement markedly impairs the benefits of FEM with geometrical flexibility. As described herein, that difficulty is solved by construction of a specially designed time-integration method for time discretization. The proposed method can use irregularly shaped elements while maintaining fourth-order accuracy in time without additional computational complexity compared to the conventional method. The dispersion and dissipation characteristics of the proposed method are examined respectively both theoretically and numerically. Moreover, the practicality of the method for solving room acoustic problems at kilohertz frequencies is presented via two numerical examples of acoustic simulations in a rectangular sound field including complex sound diffusers and in a complexly shaped concert hall. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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17 pages, 6536 KiB

Open AccessArticle

Potential of Room Acoustic Solver with Plane-Wave Enriched Finite Element Method

by Takeshi Okuzono, M Shadi Mohamed and Kimihiro Sakagami

Appl. Sci. 2020, 10(6), 1969; https://doi.org/10.3390/app10061969 - 13 Mar 2020

Cited by 16 | Viewed by 3390

Abstract

Predicting room acoustics using wave-based numerical methods has attracted great attention in recent years. Nevertheless, wave-based predictions are generally computationally expensive for room acoustics simulations because of the large dimensions of architectural spaces, the wide audible frequency ranges, the complex boundary conditions, and [...] Read more.

Predicting room acoustics using wave-based numerical methods has attracted great attention in recent years. Nevertheless, wave-based predictions are generally computationally expensive for room acoustics simulations because of the large dimensions of architectural spaces, the wide audible frequency ranges, the complex boundary conditions, and inherent error properties of numerical methods. Therefore, development of an efficient wave-based room acoustic solver with smaller computational resources is extremely important for practical applications. This paper describes a preliminary study aimed at that development. We discuss the potential of the Partition of Unity Finite Element Method (PUFEM) as a room acoustic solver through the examination with 2D real-scale room acoustic problems. Low-order finite elements enriched by plane waves propagating in various directions are used herein. We examine the PUFEM performance against a standard FEM via two-room acoustic problems in a single room and a coupled room, respectively, including frequency-dependent complex impedance boundaries of Helmholtz resonator type sound absorbers and porous sound absorbers. Results demonstrated that the PUFEM can predict wideband frequency responses accurately under a single coarse mesh with much fewer degrees of freedom than the standard FEM. The reduction reaches

O (10^{- 2})

at least, suggesting great potential of PUFEM for use as an efficient room acoustic solver. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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16 pages, 5858 KiB

Open AccessArticle

A Parametric Study of the Acoustic Performance of Resonant Absorbers Made of Micro-perforated Membranes and Perforated Panels

by Lili Pan and Francesco Martellotta

Appl. Sci. 2020, 10(5), 1581; https://doi.org/10.3390/app10051581 - 26 Feb 2020

Cited by 18 | Viewed by 4885

Abstract

Sound absorbing surfaces are being increasingly requested for the acoustical treatment of spaces, like offices and restaurants, where high aesthetic standards are requested. In these cases, perforated and micro-perforated panels may represent the ideal solution in terms of low maintenance, durability, and mechanical [...] Read more.

Sound absorbing surfaces are being increasingly requested for the acoustical treatment of spaces, like offices and restaurants, where high aesthetic standards are requested. In these cases, perforated and micro-perforated panels may represent the ideal solution in terms of low maintenance, durability, and mechanical resistance. In addition, such a solution might be conveniently realized while using optically transparent panels, which might offer extra value, as they could ensure visual contact, while remaining neutral in terms of design. The paper first investigates the reliability of prediction models by comparison with measured data. Subsequently, while taking advantage of a parametric optimization algorithm, it is shown how to design an absorber covering three octave bands, from 500 Hz to 2 kHz, with an average sound absorption coefficient of about 0.8. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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Review

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28 pages, 6458 KiB

Open AccessReview

Italian-Style Opera Houses: A Historical Review

by Dario D’Orazio

Appl. Sci. 2020, 10(13), 4613; https://doi.org/10.3390/app10134613 - 03 Jul 2020

Cited by 5 | Viewed by 5539

Abstract

Attending an opera involves a multi-sensory evaluation (acoustical, visual, and more), cultural background and other emotional parameters. The present work aims to investigate the historical development of Italian-style opera houses, from the 16th century until today. Called “Italian” due to their origin, they [...] Read more.

Attending an opera involves a multi-sensory evaluation (acoustical, visual, and more), cultural background and other emotional parameters. The present work aims to investigate the historical development of Italian-style opera houses, from the 16th century until today. Called “Italian” due to their origin, they developed thanks to the mutual influence of the genre and the building characteristics. Furthermore, the acoustics of historical opera houses is now considered as intangible cultural heritage, so it should be known and preserved. The paper addressed the state-of-the-art literature—most of which was proposed in Italian—which can be driven easily by the sharing of historical and contemporary knowledge. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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32 pages, 658 KiB

Open AccessReview

Review of Acoustic Sources Alternatives to a Dodecahedron Speaker

by Nikolaos M. Papadakis and Georgios E. Stavroulakis

Appl. Sci. 2019, 9(18), 3705; https://doi.org/10.3390/app9183705 - 06 Sep 2019

Cited by 32 | Viewed by 5125

Abstract

An omnidirectional source is required in many acoustic measurements. Commonly a dodecahedron speaker is used but due to various factors (e.g., high cost, transportation difficulties) other acoustic sources are sometimes preferred. In this review, fifteen acoustic source alternatives to a dodecahedron speaker are [...] Read more.

An omnidirectional source is required in many acoustic measurements. Commonly a dodecahedron speaker is used but due to various factors (e.g., high cost, transportation difficulties) other acoustic sources are sometimes preferred. In this review, fifteen acoustic source alternatives to a dodecahedron speaker are presented while emphasis is placed on features such as omnidirectionality, repeatability, adequate sound pressure levels, even frequency response, accuracy in measurement of acoustic parameters and fulfillment of ISO 3382-1 source requirements. Some of the alternative acoustic sources have the appropriate features to provide usable results for acoustic measurements, some have acoustic characteristics better than a dodecahedron speaker (e.g., omnidirectionality in the high-frequency range), while some can potentially fulfill the ISO 3382-1 source requirements. Collected data from this review can be used in many areas (e.g., ISO measurements, head-related transfer functions measurements) for the appropriate selection of an acoustic source according to the expected use. Finally, suggestions for uses and future work are given aimed at achieving further advances in this field. Full article

(This article belongs to the Special Issue Advances in Architectural Acoustics)

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