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Traditional acoustic design of heating, ventilation and air conditioning (HVAC) system mostly relies on the experience of designers, with significant repetition and minimal automation. To achieve the goal of intelligent design, methods such as directed acyclic graph, weighted directed adjacency matrix, and visualization were applied in the acoustic design of ventilation duct system. An algorithm was proposed to automatically calculate the noise levels at any place, whether in the duct or a specific room. The key components such as building 3D models, designing noise attenuation diagram, determining acoustic path, solving acoustic unit, and visualizing acoustic results were included in this system. The results show that this system is robust, accurate and quick to respond. The deviation between results from traditional methods and the proposed algorithm is no more than ± 2%, and the computation time is less than 0.2s, whereas the running time for some small and medium ventilation systems is within 0. 1s. The results based on this algorithm can be combined with 3D models to visualize the change of noise values and provide a reference in the design process of HVAC systems. [ABSTRACT FROM AUTHOR]

The working model of the laboratory of soundscapes of the future, a graduate laboratory inspired by the conceptual framework of Candy, Dunagan, and Schafer, is presented. The concepts of acoustic design, phonosphere, and sonor are addressed to explain the sequence of work then, the results achieved so far, and the areas of opportunity to improve this learning experience. [ABSTRACT FROM AUTHOR]

Getting close to birds is a great challenge in wildlife photography. Bird photography blinds may be the most effective and least intrusive way if properly designed. However, the acoustic design of the blinds has been overlooked so far. Herein, we present noise-cancelling blinds which allow photographing birds at close range. First, we conducted a questionnaire in the eco-tourism centre located in Yunnan, China. Thus, the birders' expectations of the indoor sound environment are determined. We then identify diverse variables to examine the impact of architectural and acoustic decisions on noise propagation. Finally, the acoustic performances of the blinds by considering the birds' hearing threshold are examined. The numerical simulations are performed in the acoustics module of Comsol MultiPhysics. Our study demonstrated that photography blinds require a strong and thorough acoustic design for both human and bird well-being. [ABSTRACT FROM AUTHOR]

The sound field model of an irregular enclosure with two elastic walls and an inclined wall is established by the modal theory. The modal parameters of the irregular enclosure are obtained by the envelope rectangular technique. The influence of the inclination wall angle on the sound field in the irregular enclosure is discussed. When the inclination angle is increased from 0° to 45°, the resonance frequencies of the acoustic enclosure are basically reduced in the frequency range of 0∼250 Hz. When the inclination angle is increased from 0° to 45° every 15° interval, the amplitude of a certain acoustic mode itself decreases, while the amplitudes of the acoustic modes coupled to it basically increase. The acoustic potential energy peaks in the enclosure basically shift to the low frequency with the increase of the inclination angle. Furthermore, the change trend of the acoustic potential energy is regular in the low-order modes, but relatively chaotic in the high-order modes. In addition, in order to verify that the accurate description of the primary sound field is the basis of effective noise control, the two-elastic plate model is deliberately treated as one-elastic plate model, and its influence on the performance of active noise control is discussed. Also, if the multi-elastic plate model is regarded as a simplified automobile cab, the research results can be used for the preliminary acoustic design of the cab; that is, the research results can be used for the acoustic design of similar models. [ABSTRACT FROM AUTHOR]

The study and analysis of the processes that determine environmental sustainability of buildings are nowadays topics of great interest for the sustainable, economic and social development of the cities. The international context presents guidelines and protocols for the energy-environmental sustainability, often aimed to assigning a sustainability label to the buildings. In Italy one of the most used rating systems is the ITACA Protocol, recently updated by the Italian Standard UNI/Pdr 2019, which through a series of criteria identifies global indicators of the sustainability of the building examined. This paper presents the potential of the ITACA protocol which could be a method for designing innovative and efficient architectures. In particular, the aspects related to the acoustic comfort are examined and how these criteria change the overall performance of a building. The evaluation of the sustainability performance was applied to a school building. Results show that an optimal acoustic quality improve over to 2 point of the final protocol score. [ABSTRACT FROM AUTHOR]

Applicability of wave-based acoustics simulation methods in the time domain has increased markedly for performing room-acoustics simulation. They can incorporate sound absorber effects appropriately with a local-reaction frequency-dependent impedance boundary condition and an extended-reaction model. However, their accuracy, efficiency and practicality against a standard frequency-domain solver in 3D room acoustics simulation are still not known well. This paper describes a performance examination of a recently developed time-domain FEM (TD-FEM) for small-room acoustics simulation. This report first describes the significantly higher efficiency of TD-FEM against a frequency-domain FEM (FD-FEM) via acoustics simulation in a small cubic room and a small meeting room, including two porous-type sound absorbers and a resonant-type sound absorber. Those sound absorbers are modeled with local-reaction frequency-dependent impedance boundary conditions and an extended-reaction model. Then, the practicality of time-domain FEM is demonstrated further by simulating the room impulse response of the meeting room under various sound absorber configurations, including the frequency component up to 6 kHz. Results demonstrated the high potential and computational benefit of time-domain FEM as a 3D small room acoustics prediction tool.

Building and room acoustics are relatively modern architectural and engineering disciplines. Nevertheless, acoustics was also a concern for buildings in the past, e.g., in theatres in ancient Greece and in Roman times. Nowadays, we spend 80–90 % of our time indoors, and sound impacts our communication and actions in an environment to a great extent. Therefore, acoustic aspects should be considered appropriately in the Environmental Quality and Global Comfort context as part of the overall aspects of building physics, although other factors (e.g., thermal, air quality, etc.) are conventionally considered more "mainstream". The ten questions considered in this paper range from the basic definitions underlying the differences between building and room acoustics, to more applied topics about how to measure, simulate and use acoustic data in the design of the built environment. Significant research activities have been conducted by acoustic experts on different aspects related to the measurements of physical properties, perceptual aspects and technological development in both the physical and virtual dimensions, thereby paving the way towards a more inclusive and healthier acoustic environment. Apart from illustrating the current state of the art, the answers to these questions point out the still existing gaps in the field and future challenges, thereby highlighting the new competencies required to support the design of the acoustic environment, focusing on the physical, physiological, and psychological needs of the users. • The views of fourteen acoustic experts (academia and industry) are presented. • The acoustic principles and application fields of buildings and rooms are defined. • A range of perspectives on objective and subjective studies is presented. • Acoustic studies should be included in decision-making processes. • Future research should integrate new competencies in acoustic design. [ABSTRACT FROM AUTHOR]

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.

In many buildings, structural concrete systems have a large impact on the building's overall weight, embodied energy, and embodied carbon. Efficient structural components could result in building weight reductions, leading to material savings and a reduced carbon footprint. Shaping of concrete slabs through structural optimization has recently seen significant interest due to advancements in digital fabrication and the potential for more sustainable and architecturally expressive designs. However, many promising optimization-based approaches to shaping slabs do not consider secondary design aspects during computational exploration, including acoustics. This paper presents a computational investigation of trade-offs between structural and acoustic objectives using a multiobjective optimization framework while designing concrete slabs with curved ribs. A series of Pareto front approximations and constrained optimization runs at specific acoustic performance levels were used to explore optimal designs, while evaluating how a computational search for competing objectives distributes structural material. Shaped slabs were then compared to conventional floor assemblies. The study shows how slab shaping impacts sound insulation and suggests how designers could incorporate structural–acoustic optimized concrete slabs in building design. [ABSTRACT FROM AUTHOR]

Active noise control (ANC) systems usually involve a large number of loudspeakers and error microphones in order to achieve noise reduction over an extended region of space. Although fundamentals of ANC theory and principles of ANC methods have been well-established over the past 40 years, applications of this technology are facing new challenges. A larger quiet zone with better noise reduction performance is always desirable in a variety of real-life scenarios. This paper presents several important factors that affect the performance of multichannel ANC systems in some popular applications such as windows with natural ventilation and quiet-zone around heads. The factors affecting acoustic design include the reflection of a baffle plate, arrangement of error sensors in open areas, and so on. In addition, different control strategies are compared and analyzed, including centralized, decentralized, and distributed strategies. All these strategies are discussed from the signal processing side, which should be considered after a proper acoustic design. One of the important aims of this paper is to provide practical guidance for acoustic design and discuss several typical control strategies for multichannel ANC systems. [ABSTRACT FROM AUTHOR]

Current development in digital design, combined with the growing awareness of the importance of building performance, had drawn attention to performance-based design (PBD) in architecture. PBD benefits both design workflow and outcome, allowing one to control the performance of the design proposal since early design phases. The paper aims to explore its current application in the acoustic field, where its potential is still little exploited in architectural practice. A set of built case studies is collected and briefly analyzed with the aim to shed some light on the state of the art of the application of acoustic performance-based design (APBD) in practice. The analysis suggests that in order to encourage the application of APBD it is needed on one side to enhance the integration and interoperability among modeling and simulation tools, and on the other side to improve the acoustic knowledge and programming skills of the architectural practitioners.

Acoustic comfort is directly related to enhanced well-being and performance of people. A typical challenge faced by architects and acousticians is to achieve adequate acoustics while maintaining the aesthetics of the space and reducing the visual aspects of acoustic materials and elements. In this study, we present a biofiber-based acoustic coating as a feasible solution to improve acoustic environments while preserving the aesthetics of spaces. An acoustic coating is a thin layer of absorption material, but the coating can be sprayed on other sound absorbing structures to make it more effective on a wide frequency range. In addition, this biofiber-based coating acts as a carbon sink during its operating life, thus reducing the carbon footprint of the building. Therefore, the coating is sustainable and is an environmental friendly solution. The absorption properties of the biofiber-based coating are demonstrated in the present study with three case studies, which all had demanding requirements to conceal the acoustic structures.

Copyright of Academic Platform - Journal of Engineering & Science is the property of Akademik Platform and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Active noise control (ANC) systems usually involve a large number of loudspeakers and error microphones in order to achieve noise reduction over an extended region of space. Although fundamentals of ANC theory and principles of ANC methods have been well-established over the past 40 years, applications of this technology are facing new challenges. A larger quiet zone with better noise reduction performance is always desirable in a variety of real-life scenarios. This paper presents several important factors that affect the performance of multichannel ANC systems in some popular applications such as windows with natural ventilation and quiet-zone around heads. The factors affecting acoustic design include the reflection of a baffle plate, arrangement of error sensors in open areas, and so on. In addition, different control strategies are compared and analyzed, including centralized, decentralized, and distributed strategies. All these strategies are discussed from the signal processing side, which should be considered after a proper acoustic design. One of the important aims of this paper is to provide practical guidance for acoustic design and discuss several typical control strategies for multichannel ANC systems.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eight participants with a musical background were asked to reflect in depth on their experience of sonic environments through a structured questionnaire answered in either oral or written form. Six of these interviews took place at the Zentrum für Kunst und Medien in Karlsruhe, and two in London, to provide contrasting comparison terms. The questionnaire invited the participants to progress in their reasoning from the description of the present sonic environment to the formulation of thoughts on the acoustic design of spaces, the educational potential of soundwalking practices and the elicitation of places with aural character from their memory. The interview transcripts were qualitatively analysed through the grounded theory method with the aim to detail the underlying mechanisms towards the appraisal or criticism for an acoustic environment. Acoustic and psychoacoustic indicators were extracted from the binaural measurements of the interview settings to provide objective grounds for comparison. Five concurrent factors were identified as involved in the quality attribution process: purpose affordance, affective impact, memory, ecological awareness and acoustic design. [ABSTRACT FROM AUTHOR]

This article discusses the integration of acoustic design approaches into architectural design education settings. Solving architectural acoustic problems has been for centuries one of the primary aims of theories and experiments in acoustics. Recent contributions offered by the soundscape approach have highlighted broader desirable aims which acoustic designers should pursue, fostering ecological reasoning on the acoustic environment and its perception as a whole. Drawing from the available literature, some examples are brought to show the integration of architectural acoustics and soundscape approaches into the realm of architectural design education, highlighting the significance of specific design situations and aural training techniques in learning contexts. [ABSTRACT FROM AUTHOR]

Due to their disproportionate geometries and uneven distribution of sound, the interior sound field analysis of subway stations has always been challenging. The field necessitates reliable tools for real-case design applications, while the research and discussions on the topic are still ongoing. This study compares two major room acoustics simulation approaches, namely ray tracing and diffusion equation modeling (DEM) in order to assist future acoustical designs of subway stations. Two cases of Istanbul Metropolitan metro lines are selected, namely station BAG with a circular cross section and station USK with rectangular cross section. The reverberation time and relative sound pressure level results from field tests are compared with those obtained by the ray tracing and DEM. The results emphasized the validity as well as limitations of each method over discussed metrics with given geometric layouts and material characteristics of the subway stations. [ABSTRACT FROM AUTHOR]

As part of this study, the acoustic properties of the Adana Metropolitan Municipality Concert Hall were evaluated. The acoustic evaluations for the current condition of the actively used concert hall that accommodates up to 536 people, are based on the objective parameters of sound: reverberation time (RT), early decay time (EDT), clarity (C80), lateral energy fraction (LF) and center time (Ts). Acoustic simulation software's were used to gather the objective parameter of sound. A 3D model of the concert hall was prepared in SketchUp 2017 to be used in simulations. Utilizing the simulation done in ODEON Room Acoustics Software 14.00 Combined the concert hall was analyzed. This study is based on the acoustic simulations and the characteristic of architectural and acoustic finish elements of the Adana Metropolitan Municipality Concert Hall; and also, on the research of the concert halls accordance to national and international standards and the result of said research. Changes were proposed in the architectural and acoustic finish elements of the hall, so as to optimize the acoustic frequency values that were out of the acceptable range stated in their literature. [ABSTRACT FROM AUTHOR]

Featured Application: Providing a new research perspective for the development of acoustic requirements in naturally ventilated buildings and of façade control strategies enabling NV. The indoor-outdoor connection provided by ventilation openings has been so far a limiting factor in the use of natural ventilation (NV), due to the apparent conflict between ventilation needs and the intrusion of external noise. This limiting factor impedes naturally ventilated buildings meeting the acoustic criteria set by standards and rating protocols, which are reviewed in this paper for residential buildings. The criteria reflect a general effort to minimize noise annoyance by reducing indoor sound levels, typically without a distinction based on a ventilation strategy. Research has developed a number of solutions, discussed here, that try to guarantee ventilation without compromising façade noise insulation, but, currently, none have been adopted on a large scale. This concept paper highlights the main limits of the current approach. First, a fragmented view towards indoor environmental quality has not included consideration of the following acoustic criteria: (i) how buildings are designed and operated to meet multiple needs other than acoustical ones (e.g., ventilation, visual, and cooling needs) and (ii) how people respond to multiple simultaneous environmental factors. Secondly, the lack of a perceptual perspective has led acoustic criteria to neglect the multiple cognitive and behavioral factors impinging on comfort in naturally ventilated houses. Indeed, factors such as the connection with the outside and the sense of control over one's environment may induce "adaptive acoustic comfort" opportunities that are worth investigating. The mere use of different sound level limits would not be enough to define criteria tailored to the complex user–building interaction that occurs under NV conditions. More holistic and human-centered approaches are required to guarantee not only neutrally but even positively perceived indoor acoustic environments. For this reason, this paper considers this apparent conflict from a soundscape viewpoint, in order to expose still unexplored lines of research. By underpinning a perceptual perspective and by contextualizing it, the indoor soundscape approach provides a framework capable of overcoming the limits of the traditional noise control approach. This could provide the opportunity to foster a wider adoption of NV as a passive design strategy that enhances user health and well-being, while enabling low-cost, and low-energy cooling and ventilation, thereby contributing to current climate change challenges. [ABSTRACT FROM AUTHOR]

A common problem in acoustic design is the placement of speakers or receivers for public address systems, telecommunications, and home smart speakers or digital personal assistants. We present a novel algorithm to automatically place a speaker or receiver in a room to improve the intelligibility of spoken phrases in a design. Our technique uses a sound propagation optimization formulation to maximize the Speech Transmission Index (STI) by computing an optimal location of the sound receiver. We use an efficient and accurate hybrid sound propagation technique on complex 3D models to compute the Room Impulse Responses (RIR) and evaluate their impact on the STI. The overall algorithm computes a globally optimal position of the receiver that reduces the effects of reverberation and noise over many source positions. We evaluate our algorithm on various indoor 3D models, all showing significant improvement in STI, based on accurate sound propagation. [ABSTRACT FROM AUTHOR]

Although certain vibration and noise control technologies are maturing, such as vibration absorption, vibration isolation, sound absorption and sound insulation, and new methods for specific frequency bands or special environments have been proposed unceasingly, there is still no guarantee that practical effective vibration and noise reduction can be obtained. An important constraint for vibration and noise reduction is the lack of a system concept, and the integrity and relevance of such practical systems as ship structure have not obtained enough attention. We have tried to use the system engineering theory in guiding vibration and noise reduction, and have already achieved certain effects. Based on the system concept, the noise control of a petroleum pipeline production workshop has been completed satisfactorily, and the abnormal noise source identification of an airplane has been accomplished successfully. We want to share our experience and suggestions to promote the popularization of the system engineering theory in vibration and noise control.

The present work is about an acoustic design for a former church converted into a multi-purpose auditorium. The current status of the hall has been classified by means of an acoustic measurements campaign complying with technical standards requirements. A numerical model, which has been calibrated through the measured values, led to the development of the acoustic design that includes sustainable and not-invasive interventions. In contrast with the practical habits, which would use a large amount of sound absorbing materials, an array of suspended reflecting panels over the musicians positions has been introduced. Exploiting the reflecting and scattering properties of those objects, sound clarity and speech definition improve. All the treatments are validated using numerical simulation softwares in order to estimate the efficiency of the whole improvement proposal.

• The paper describes the design process to achieve the requested acoustic quality, accepting the challenge to resemble a classical theatre whilst including modern facilities, equipment and variable acoustic elements which harmoniously lends itself to multipurpose uses, and increasing the sightlines quality. • The acoustic design methodology for an the Opera House is explained in detail. • computer simulations to support the architectural acoustic design process are analysed together with the results of measurements in a 1:20 wooden model to predict and evaluate the acoustic behaviour of the hall. • To evaluate the predictive acoustic analysis, measurements on site complete the article. Conclusions follow in which the acoustic results show that the classic form of the State Theatre of Opera and Ballet of Nur Sultan is compatible with the most modern technological and functional needs of a new opera house with multipurpose functions, that sightlines can be improved and that the acoustic quality similar to one of the most important Italian Baroque theatres is achievable. The paper explains the design of the new Opera House in Astana as a landmark building for the new capital of Kazakhstan, characterized by multifunctional functionalities to welcome different kinds of activities. As requested by the Kazakhstan government, the building is a semi-classical theatre with traditional country decorations. The four tiers of balconies and the upper gallery form a modest house shoe shape with a seat capacity of ca. 1300 spectators, a volume of 11.400 m3 and a Reverberation Time, with empty hall, of 1.7 s (house curtain open). The paper describes the acoustic field and the design process to achieve an acoustic quality similar to that of the most famous Baroque Opera Houses, and its ability to resemble a classical theatre whilst also harmoniously including modern facilities and equipment. The evolution of a historic theatre in a modern design concept is explained. Computer simulations were conducted throughout the design period and a 1:20 wooden model was built to test the process, followed by final measurements on site. [ABSTRACT FROM AUTHOR]

Abstract One characteristic of railway stations in China is that the entrance hall, ticket office, integrated waiting hall and auxiliary space are all concentrated in a large span of space, forming a unified whole space. However, the multi-function fusion in such a large space results in a series of acoustic problems, such as long reverberation time, high environmental noise and poor language articulation. Therefore, it is necessary to study the acoustic environment of railway stations in China. In this study, the sound field characteristics of the typical railway station are studied to reveal its law of sound propagation. Next, subjective evaluation and objective experiments are carried out to study the acoustic environment and comfort in the waiting hall. Finally, based on the comparative analysis of various influential factors, such as sound source and sound field, this paper advances some suggestions for the acoustical design of high-speed railway stations. [ABSTRACT FROM AUTHOR]

Vehicle noise is one of the main sources of complaints because it is widespread and active in almost all environments, from urban areas to rural context. The present work aims to describe a practical procedure to design silencers for off-road motorcycles so that, once produced, they are lightweight, do not affect the engine performances and cut noise emissions to a sustainable limit. The required noise reduction, usually around 35-40 dB, can be achieved only by carefully designing the exhaust system. The first part of the paper provides the theoretical background of noise propagation in ducts, describes the main attenuation devices as tools the designer can use in the development process and outlines the workflow. In the second part, a case study of silencer optimization is presented: the noise emitted by a real off-road motorcycle is characterized and, once the sound pressure level and the mass flow generated by the engine are known, a silencer fulfilling noise attenuation, size and pressure drop requirements is designed, 3D-modeled and rendered. The outcome of the acoustic design process can be used to perform virtual sound quality tests, which can be of interest for manufacturers to catch the attention of passionate users. [ABSTRACT FROM AUTHOR]

Results of verifying the levels and directional characteristics of sound radiation are presented for a finite-element numerical model of a submerged inhomogeneous shell. The error in numerical modeling of directional characteristics is determined for sound radiation from shell parts with one-layer (shell-liquid) and multilayer (shell-liquid-shell-liquid) structures. [ABSTRACT FROM AUTHOR]

Environmental noises can have a large impact on workplace productivity and health. We address the problem of designing large CAD structures that automatically meet the noise guidelines and standards. We present a novel approach that determines the optimal placement of sound sources such as generators, machinery, fans and HVAC appliances that can conform to these design requirements in indoor scenes. Our approach uses a hybrid sound propagation algorithm that combines elements of both geometric and wave-based techniques for handling higher and lower frequencies, respectively. We use an efficient simulated annealing approach for acoustic optimization that uses impulse response caching and sound source clustering to improve the convergence time. Finally, we present our approach in the context of a traditional CAD pipeline, where noise conformance requirements can be integrated during the early stages of the digital design phase. We highlight the approach’s performance on many complex CAD models corresponding to an office and a warehouse. [ABSTRACT FROM AUTHOR]