The link to subjective parameters and objective parameters in the field of room acoustics has been the source of much research. This thesis surveys some of the available objective room acoustical analysis methods, quantify their advantages and disadvantages with respect to the measurement of acoustical qualities of professionally operated critical listing rooms, and implements these methods in a range of critical listening rooms. In conjunction with the objective room analysis, a subjective component of research was also performed. A series of anechoically recorded standard instrument sounds were presented to professional listeners in their critical listening spaces with the listeners asked to alter the sounds to taste: to

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Summary: Acoustic differences were evaluated among three choral arrangements and two choral textures recorded at three microphone locations. A choir was recorded when singing two musical selections of different choral texture, one homophonic and one polyphonic. Both musical selections were sung in three choral arrangements: block sectional, sectional-in-columns, and mixed. Microphones were placed at the level of the choristers, the conductor, and the audience. The recordings at each location were analyzed using long-term average spectrum (LTAS). The LTAS from the mixed arrangement exhibited more signal amplitude than the other arrangements in the range of 1000-3500 Hz. When considering the musical selections, the chorus produced more signal amplitude in the region of 1800-2200 Hz for the homophonic selection. In addition, the LTAS produced by the choir for the homophonic selection varied across the microphone locations. As for the microphone location, the LTAS of the signal detected directly in front of the chorus had a greater slope than the other two locations. Thus, the acoustic signal near the choristers differed from the signals near the conductor and in the audience. Conductors may be using acoustic information from the region of the second and third formants when they decide how to arrange a choir for a particular musical selection.

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WHAT? The interconnectedness of acoustics and architecture is one that is too often overlooked. Many architects tend to focus solely on visual aesthetics, when in reality, it is the architect's job to create a space that is pleasing to all of the senses. Although all senses are important to the experience of a space, in most instances architects only have control over sight, sound, and touch. While architects usually make calculated decisions to improve the visual and touch experience, it seems that acoustics are an afterthought and rarely brought to attention unless there are special requests from the client or complaints from the user. WHY? The issues caused by poor acoustic considerations range from a space that is simply annoying to occupy, such as a desk fixed under the constant hum of an air vent, to rooms that are unusable for their intended purpose, such as a lecture hall with a long reverberation time making it impossible to distinguish syllables and understand the speaker. In the case of musical performances, the acoustical considerations of a design can completely alter the way sound travels from the performers to the audience. For example, a rock concert in a small room finished in marble would be unbearable, while a high school orchestra would be inaudible from the back of a large amphitheater. Therefore, it is important to design a space in which the architecture strengthens the performances that it was intended for. HOW? In this thesis I examine the balance of visual aesthetics and acoustical performance into a single building, the Shrine Hill Music Center. Located in Roanoke, Virginia, the Shrine Hill Music Center is imagined as a supplement to the surrounding educational buildings by housing a small performance hall, several practice rooms, and a recording studio to be enjoyed by students and members of the community. During my research I found myself asking questions such as; what architectural choices can be made that are both visually and audibly pleasing? What acoustical factors should be considered when designing a performance hall and how do these differ from those of a practice room or a recording studio? Is there an opportunity to tune a space just as one is able to tune an instrument? By the end I was not only left with a building that utilizes the architecture to enhance the acoustics, but also an abundance of acoustical knowledge that will benefit me in my future endeavors as a designer. / Master of Architecture / The interconnectedness of acoustics and architecture is one that is too often overlooked. Potential issues caused by poor acoustic considerations range from a space that is simply annoying to occupy, such as a desk fixed under the constant hum of an air vent, to rooms that are unusable for their intended purpose, such as a poorly treated lecture hall where it impossible to distinguish syllables and understand the speaker. In the case of musical performances, the acoustical considerations of a design can completely alter the way sound travels from the performers to the audience. Therefore, it is important to design a space in which the architecture strengthens the performances that it was intended for. In this thesis I examine the balance of visual aesthetics and acoustical performance into a single building, the Shrine Hill Music Center. I found myself asking questions such as; what architectural choices can be made that are both visually and audibly pleasing? What acoustical factors should be considered when designing a performance hall and how do these differ from those of a practice room or a recording studio? Is there an opportunity to tune a space just as one is able to tune an instrument? By the end I was not only left with a building that utilizes the architecture to enhance the acoustics, but also an abundance of acoustical knowledge that will benefit me in my future endeavors as a designer.

Orientador: João Antonio Pereira / Resumo: A indústria fonográfica com o advento dos equipamentos digitais de gravação sofreu grandes transformações nos últimos anos. A mudança mais marcante é a migração dos músicos que antes trabalhavam com grandes gravadoras e hoje trabalham de forma independente, com estúdios construídos ou adaptados em suas residências, os chamados home studios. Seja em um grande estúdio profissional de gravação, ou em um home studio, o estudo da acústica do local é imprescindível para se obter boa qualidade nas gravações. Uma das áreas aplicadas da acústica é a avaliação e desenvolvimento de ambientes utilizados para gravações de áudio. Essa área contempla diversas avaliações de grande valia, quando se trata da garantia da qualidade acústica das salas em um home studio. Reverberações, isolamento sonoro, entre outras variáveis de projeto definem parâmetros acústicos do ambiente. A obtenção destes parâmetros e adaptações do local para diferentes usos, entre outras características utilizadas para avaliação da qualidade sonora dos ambientes, podem ser dadas através do estudo e avaliação do modelo acústico do estúdio, visto que esses parâmetros estão diretamente relacionados com os materiais construtivos, dimensões e arquitetura do ambiente. Este trabalho teve como objetivo o estudo do efeito desses parâmetros na acústica dos ambientes e a criação de modelos numéricos representativos de predição acústica, a partir da análise e avaliação em dois estúdios diferentes. Assim, provendo embasamento teórico-... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The phonographic industry, with the advent of digital recording equipments, su ered great transformations in the last few years. The most remarcable change is the migration of musicians that used to work with great record labels before and nowadays work in an independent way, with studios constructed in their residences, the so called home studios. Whether in a large professional recording studio, or at an home studio, the study of local acoustics is imprescindible for obtaining good recording quality. One of the applied areas of acoustics is the valuation and development of enviroments used for audio recordings. This front of study includes many evaluations of great worth when it comes to guaranteeing the acoustic quality in a home studio. Reverberations, sound insulation, between other variables de ne the acoustic quality of the enviroment. The obtention of these parameters and adptations of the room for di erent kind of usage, along with other characteristics utilized for the valuation of acoustic quality of enviroments, may be given through study and valuation of an acoustic model of the studio, since these parameters are directly related to the building materials, dimensions and architecture of the environment. The objective of this work was to study the e ect of these parameters on the acoustics of the environments and the creation of representative numerical models of acoustic prediction, from the analysis and evaluation in two di erent studios, so that it is possible ... (Complete abstract click electronic access below) / Mestre

Time Reversal (TR) is a technique that may be used to focus an acoustic signal at a particular point in space. While many variables contribute to the quality of TR focusing of sound in a particular room, the most important have been shown to be the number of sound sources, signal bandwidth and absorption properties of the medium [Ribay et al., J. Acoust. Soc. Am. 117(5), 2866-2872 (2005)]. However, the effect of room size on TR focusing has not been explored. Using the image source method algorithm proposed by Allen and Berkley [J. Allen and D. A. Berkley, J. Acoust. Soc. Am. 65(4), 943-950 (1979)], TR focusing was simulated in a variety of rooms with different absorption and volume properties. Experiments are also conducted in a couple rooms to verify the simulations. The maximum focal amplitude, the temporal focus quality, and the spatial focus clarity are defined and calculated for each simulation. The results are used to determine the effects of absorption and room volume on TR. Less absorption increases the amplitude of the focusing and spatial clarity while decreasing temporal quality. Dissimilarly, larger volumes decrease focal amplitude and spatial clarity while increasing temporal quality. This thesis also explores the placement of individual transducers within a room. It also compares the layout of several source transducers used for a reciprocal time reversal process. Maximum focal amplitude and spatial clarity are found to increase when the focus location is dual coplanar to the source location while temporal quality is found to decrease in comparison to the case when source and focal location share only one plane. Maximum focal amplitude is found to be at a minimum when the focus location is at the critical distance and increases closer and farther away from the source, while temporal quality steadily decreases and spatial clarity steadily increases farther from the source. The maximum focal amplitude and the temporal quality are not greatly affected by the type of array layout, but a circular array is ideal for maximizing spatial clarity.

This theoretical diploma thesis deals with room acoustics and the closely related issue of reverberation. Part of the work is a drafting of acoustic modifications of the church based on manual calculation, which was further modified in a specialized software Odeon Room Acoustics Program. For the surrounding buildings of the church was created a study of the noise in a program Hluk+ in order to assess what will be the noise impact of this new building on its surroundings. On the basis of specialization was created several proposals for the design of the church. The approximate proposal of the double-plated dome, a system of drainage of the coupling neck, and the ways the anchor of the hard large-format window glazing. The result of the work is suitable design of acoustic adjustments and improvement of the listening qualities for the future construction of this church.

Wave-based models of sound propagation can be used to predict and synthesize sounds as they would be heard naturally in room acoustic environments. The numerical simulation of such models with traditional time-stepping grid-based methods can be an expensive process, due to the sheer size of listening environments (e.g., auditoriums and concert halls) and due to the temporal resolution required by audio rates that resolve frequencies up to the limit of human hearing. Finite difference methods comprise a simple starting point for such simulations, but they are known to suffer from approximation errors that may necessitate expensive grid refinements in order to achieve sufficient levels of accuracy. As such, a significant amount of research has gone into designing finite difference methods that are highly accurate while remaining computationally efficient. The problem of designing and using accurate finite difference schemes is compounded by the fact that room acoustics models require complex boundary conditions to model frequency-dependent wall impedances over non-trivial geometries. The implementation of such boundary conditions in a numerically stable manner has been a challenge for some time. Stable boundary conditions for finite difference room acoustics simulations have been formulated in the past, but generally they have only been useful in modelling trivial geometries (e.g., idealised shoebox halls). Finite volume methods have recently been shown to be a viable solution to the problem of complex boundary conditions over non-trivial geometries, and they also allow for the use of energy methods for numerical stability analyses. Finite volume methods lend themselves naturally to fully unstructured grids and they can simplify to the types of grids typically used in finite difference methods. This allows for room acoustics simulation models that balance the simplicity of finite difference methods for wave propagation in air with the detail of finite volume methods for the modelling of complex boundaries. This thesis is an exploration of these two distinct, yet related, approaches to wave-based room acoustic simulations. The overarching theme in this investigation is the balance between accuracy, computational efficiency, and numerical stability. Higher-order and optimised schemes in two and three spatial dimensions are derived and compared, towards the goal of finding accurate and efficient finite difference schemes. Numerical stability is analysed using frequency-domain analyses, as well as energy techniques whenever possible, allowing for stable and frequency-dependent boundary conditions appropriate for room acoustics modelling. Along the way, the use of non-Cartesian grids is investigated, geometric relationships between certain finite difference and finite volume schemes are explored, and some problems associated to staircasing effects at boundaries are considered. Also, models of sound absorption in air are incorporated into these numerical schemes, using physical parameters that are appropriate for room acoustic scenarios.

Book Summary: Chermak and Musiek's two-volume, award-winning handbooks are back in newly revised editions. Extensively revised and expanded, Volume II provides expanded coverage of rehabilitative and professional issues, detailing intervention strategies for children and adults. Volume I provides comprehensive coverage of the auditory neuroscience and clinical science needed to accurately diagnose the range of developmental and acquired central auditory processing disorders in children, adults, and older adults. Building on the excellence achieved with the best-selling 1st editions which earned the 2007 Speech, Language, and Hearing Book of the Year Award the second editions include contributions from world-renowned authors detailing major advances in auditory neuroscience and cognitive science; diagnosis; best practice intervention strategies in clinical and school settings; as well as emerging and future directions in diagnosis and intervention.