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1
Durany, Vendrell Jaume. "Geometrical room acoustics: ray based simulation for room acoustics". Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/395190.
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L’acústica de sales és la ciència encarregada d’estudiar la propagació del so en
entorns tancats. La informació acústica de qualsevol entorn, coneguda com la
resposta impulsional, s’expressa en termes del camp acústic com una funció de
l’espai i el temps. La formulació analítica de la distribució de les variables del so és,
en general, extremadament complexa d’obtenir i només existeixen solucions
d’escenaris molt simples i irreals. Per tant, l’ús d’ordinadors per solucionar aquest
tipus de problemes ha emergit com una alternativa adequada per calular funcions de
resposta.
En aquesta Tesi ens hem centrat en l’ús de mètodes basats en rajos per calcular
funcions de resposta. Més concretament, presentem el disseny i la implementació
d’un motor de traçat de rajos que calcula funcions de resposta en cualsevol entorn
virtual, obtenint no només la funció de resposta per la presió sinó també pel vector de
velocitats del camp acústic. Amb aquesta informació extra tenim totes les dades
necessàries per modelar la propagació del so i podem de forma natural espacialitzar
un so per qualsevol configuració d’altaveus.
Aquesta recerca contribueix als aspectes principals del càlcul de funcions de resposta
utilitzant mètodes basats en rajos. El motor de traçat de rajos que presentem inclou un
mètode desenvolupat per aplicar la solució analítica de la Funció de Distribució
Acústica de Reflectància Bidireccional (A-BRDF) al Model de Dispersió Basat en
Vectors (VBS), fet que redueix molt notablement el cost computacional.Room acoustics is the science devoted to study sound propagation in enclosures where the sound conduction medium is bounded on all sides by walls, ceiling and floor. The acoustic information of any room, the so-called impulse response, is expressed in terms of the acoustic field as a function of space and time. The analytical formulation of the sound variables distribution is, in general, extremely hard to obtain and there only exist solutions of very simple and unrealistic scenarios. Therefore the use of computers for solving this type of problems has emerged as a proper alternative to calculate impulse responses. In this Thesis we focus on the use of the ray-based methods to compute impulse responses. More precisely, we present the design and implementation of a sound ray tracing engine that computes the impulse response in any given environment not only for the pressure but also for the velocity vector of the acoustic field. With this extra information we have all the necessary data to model the propagation of sound and we can then naturally spatialize the sound to any speakers layout. This research contributes to the main aspects in the computation of impulse responses using a ray-based approach. The presented ray tracing engine includes a method developed to apply the analytical solution for the Acoustic Bidirectional Reflectance Distribution Function (A-BRDF) in the Vector Based Scattering Model (VBS), which reduces dramatically the computational cost.
2
Liddy, David W. Holmes John F. "Acoustic room de-reverberation using time-reversal acoustics /". Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA374579.
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Thesis (M.S. in Applied Physics) Naval Postgraduate School, September 1999."September 1999". Thesis advisor(s):, Andrés Larraza, Bruce C. Denardo. Includes bibliographical references (p. 49). Also available online.
3
Liddy, David W., i John F. Holmes. "Acoustic room de-reverberation using time-reversal acoustics". Thesis, Monterey, California: Naval Postgraduate School, 1999. http://hdl.handle.net/10945/13698.
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This thesis probes the performance of one-channel time-reversal acoustics in a chamber in terms of the geometry of the cavity. In particular, a rectangular chamber is compared to an enclosure that has a stadium shape. The mode structure in the rectangular cavity is highly symmetric, while it is highly irregular in the stadium-shaped cavity. Time- reversal acoustic techniques produce an improved focus in the latter. The focusing quality is determined as a function of frequency, time-reversal window size, and spatial extent. A scheme for encrypted acoustic communication, both in air and underwater, that uses multiple broadband signals with identical bandwidth, Hanning window source spectra, and center frequencies separated by half the bandwidth, allowing for null detection between adjacent signals, is successfully investigated.
4
Smurzynski, Jacek. "Acoustic Foundations of Signal Enhancement and Room Acoustics". Digital Commons @ East Tennessee State University, 2007. https://www.amzn.com/1597565628.
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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.
5
Hatlevik, Espen. "Are Musicians Affected by Room Acoustics in Rehearsal Rooms?" Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18839.
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This study has investigated to what extent musicians adjust their source levels to different music rehearsal rooms. In the experiment, six amateur musicians were to perform the same song i four different rehearsal rooms, by first singing, then by playing guitar and last by combining singing with guitar playing. All sound sources were recorded and analyzed. The results shows that the average musician adjusts his source levels to the rehearsal room and that most of the adjustments are made in the guitar playing. Looking at the individual musician there are some that do not show any signs as to being affected by the rooms, and there are some that shows clear signs of being affected by the rehearsal room. The result also shows that the musicians are affected differently by different acoustic parameters, whereas the strength shows the least correlation and reverberation time shows the most correlation to the adjustment made by the average musician.
6
Priede, Gareth. "Room acoustics : an investigation into the computer simulation of room acoustics, with special reference to Jameson Hall". Thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/5120.
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Bibliography: leaves 138-141.This thesis consists of essentially two parts. The first deals with the theory and measurement of room acoustics while the second examines the room acoustic prediction methods.
7
Zhang, Wei. "Simulation and experimental study of room acoustics". Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27311.
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Sound propagation is a complex subject, especially in an enclosure. The study of room acoustics involves not only a research into how sound is propagated in a room, but also a search into how to measure sound under different condition and how to control sound in the case of various wall materials.
For an acoustical environment, there are three separated parts: sound sources, room acoustics, and the listens. These three items form a source-medium-receiver chain, which is typical for most of communication models. In this thesis, the image method is applied to predict the acoustical quality of a real room, and the experiment for room acoustic measurement is set up. The simulation model using image method proved the design of the measurement system is efficient for room acoustics.
8
Spa, Carvajal Carlos. "Time-domain numerical methods in room acoustics simulations". Doctoral thesis, Universitat Pompeu Fabra, 2009. http://hdl.handle.net/10803/7565.
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L'acústica de sales s'encarrega de l'estudi del comportament de les ones sonores en espais tancats.La informació acústica de qualsevol entorn, coneguda com la resposta impulsional, pot ser expressada en termes del camp acústic com una funció de l'espai i el temps. En general, és impossible obtenir solucions analítiques de funcions resposta en habitacions reals. Per tant, en aquests últims anys, l'ús d'ordinadors per resoldre aquest tipus de problemes ha emergit com una solució adecuada per calcular respostes impulsionals.En aquesta Tesi hem centrat el nostre anàlisis en els mètodes basats en el comportament ondulatori dins del domini temporal. Més concretament, estudiem en detall les formulacions més importants del mètode de Diferències Finites, el qual s'utilitza en moltes aplicacions d'acústica de sales, i el recentment proposat mètode PseudoEspectral de Fourier. Ambdós mètodes es basen en la formulació discreta de les equacions analítiques que descriuen els fenòmens acústics en espais tancats.
Aquesta obra contribueix en els aspectes més importants en el càlcul numèric de respostes impulsionals: la propagació del so, la generació de fonts i les condicions de contorn de reactància local.
Room acoustics is the science concerned to study the behavior of sound waves in enclosed rooms. The acoustic information of any room, the so called impulse response, is expressed in terms of the acoustic field as a function of space and time. In general terms, it is nearly impossible to find analytical impulse responses of real rooms. Therefore, in the recent years, the use of computers for solving this type of problems has emerged as a proper alternative to calculate the impulse responses.
In this Thesis we focus on the analysis of the wavebased methods in the timedomain. More concretely, we study in detail the main formulations of FiniteDifference methods, which have been used in many room acoustics applications, and the recently proposed Fourier PseudoSpectral methods. Both methods are based on the discrete formulations of the analytical equations that describe the sound phenomena in enclosed rooms.
This work contributes to the main aspects in the computation of impulse responses: the wave propagation, the source generation and the locallyreacting boundary conditions.
9
Murphy, Damian Thomas. "Digital waveguide mesh topologies in room acoustics modelling". Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313846.
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Hargreaves, J. A. "Time domain boundary element method for room acoustics". Thesis, University of Salford, 2007. http://usir.salford.ac.uk/16604/.
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This thesis is about improving the suitability of the time domain Boundary Element Method (BEM) for predicting the scattering from surface treatments used to improve the acoustics of rooms. The discretised integral equations are typically solved by marching on in time from initial silence; however, this being iterative has potential for divergence. Such instability and high computational cost have prohibited the time domain BEM from widespread use. The underlying integral equation is known to not possess unique solutions at certain frequencies, physically interpreted as cavity resonances, and these manifest as resonant poles, all excited and potentially divergent due to numerical error. This has been addressed by others using the combined field integral equation; an approach built upon in this thesis. Accuracy and stability may also be compromised by poor discretisation and integration accuracy. The latter is investigated on real-world surfaces, demonstrating that the popular Gaussian integration schemes are not suitable in some circumstances. Instead a contour integration scheme capable of resolving the integrands‟ singular nature is developed. Schroeder diffusers are Room Acoustic treatments which comprise wells separated by thin fins. The algorithm is extended to model such surfaces, applying the combined field integral equation to the body and an open surface model to the fins. It is shown that this improves stability over an all open surface model. A new model for compliant surfaces is developed, comparable to the surface impedance model used in the frequency domain. This is implemented for surfaces with welled and absorbing sections, permitting modelling of a Schroeder diffuser as a box with surface impedances that simulate the delayed reflections caused by the wells. A Binary Amplitude Diffuser - a partially absorbing diffuser - is also modelled. These new models achieve good accuracy but not universal stability and avenues of future research are proposed to address the latter issue.
11
HAND, SCOTT ANTHONY. "ADAPTABLE ACOUSTICS IN MULTI-USE MUSIC PERFORMANCE SPACES". University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1083634977.
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Kuster, Martin. "Inverse methods in room acoustics with under-determined data and applications to virtual acoustics". Thesis, Queen's University Belfast, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486233.
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With the advent of commercial surround sound systems there is a growing demand for 11 system that can convert existing mono and stereo recor~ings into a surround sound recording. A part of this problem is to generate the reverberation for the additional audio channels from the reverberation in the mono or stereo recording. . , In thi~ thesis, it is investigated whether a room model can be constructed from one or two room impulse responses and in which a virtual surround sound recording can then be perfonned. The estimation of the room model parameters is based on the three well-mown room acoustic models; the geometrical acoustic model with specular reflections, the eigenmode model and the diffuse field model. It is shown that the scope with the geometrical acoustic and the eigenmode model is limited but it is possible to obtain useful and consistent results for the room volume and the source-to-receiver distance from the diffuse field model. Based on these findings, the problem of generating multiple room impulse responses from one or two input room impulse response(s) is approached slightly differently. The very early part of the room impulse responses (the early reflections) is generated by a geometrical model with specular and diffuse reflections. The remainder of the room impulse responses are copies of the input room impulses obtained by convolution with a set of filters that control the coherence between them. The values for the coherence are given by expressions for the coherence between microphones with first-order directivity in a diffuse field and these expressions are derived in the thesis. The results from objective and subjective tests indicate that this method works successfully.
13
Ljung, Robert. "Room acoustics and cognitive load when listening to speech". Doctoral thesis, Luleå tekniska universitet, Arbetsvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18057.
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The present thesis investigated the effects of background noise or a long reverberation time in learning situations. All studies used spoken texts that were presented above the speech intelligibility threshold, but were degraded enough to make listening more effortful. The basic hypothesis for the whole project was that listening to speech in a bad acoustic environment should increase the cognitive load for the listener, which should impair memory of the text. In Paper I the auditory stimuli were lists of words and sentences that were degraded by a background noise. Paper II was a replication of the experiment from paper I, but the independent variable was changed from the level of the background noise to reverberation time. Paper III included two experiments where the stimulus material was 10 minutes lectures.Paper IV included two studies. The first experiment investigated whether serial recall performance is affected when words are presented in long reverberation time (Exp 1a). In experiment 1b word lists were presented in long or short reverberation time or with a background noise. The stimuli were recorded in one classroom with extremely good and one with very bad acoustic design. In experiment 2 word lists with many or few phonological neighbours were presented with long or short reverberation time. In all studies some measure of working memory capacity was included. Taken together, the overall results could be summarized in two sentences: Hearing what is said is a necessary but not a sufficient criterion for people to remember what is said, which means that spoken information should be heard without special effort, otherwise proper learning is jeopardized. No consistent relation was found between working memory capacity and the learning effect in the unfavorable listening conditions.Godkänd; 2010; 20100416 (roblju); DISPUTATION Ämnesområde: Teknisk psykologi/Engineering Psychology Opponent: Docent Mats E. Nilsson, Stockholms universitet Ordförande: Professor Håkan Alm, Luleå tekniska universitet Tid: Torsdag den 3 juni 2010, kl 14.00 Plats: F 436, Luleå tekniska universitet
14
Wu, Tsan-Ming. "Statistical impulse reponse modeling and dereverberation for room acoustics". Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/14932.
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Frey, Johannes [Verfasser]. "Pre-attentive processing of room acoustics / Johannes Daniel Frey". Hamburg : Helmut-Schmidt-Universität, Bibliothek, 2017. http://d-nb.info/1131558847/34.
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Yadav, Manuj. "Loudness of the singing voice: A room acoustics perspective". Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15653.
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This thesis is examining ectophonic (sounds created outside the human body) and autophonic (sound from one’s own voice) loudness perception for the operatic voice, within the context of room acoustics. Ectophonic loudness perception was modelled within the context of room acoustics for the operatic voice in chapter two. These models were then used to explore the loudness envelope of the messa di voce (MDV), where psychoacoustically based measures were shown to perform better than physical acoustic measures used in previous studies. The third chapter addressed autophonic loudness perception, while presenting limitations in modelling it in a manner similar to ectophonic loudness models. Some of these limitations were addressed in chapter four with two experiments where autophonic loudness of opera singers was explored using direct psychoacoustical scaling methods, within simulated room acoustic environments. In the first experiment, a power law relationship between autophonic loudness and the sound pressures produced was noticed for the magnitude production task, with different power law exponents for different phonemes. The contribution of room acoustics for autophonic loudness scaling was not statistically significant. Lombard slope, as it applies to autophonic perception and room acoustics was also studied, with some evidence found in support. The second experiment in chapter four explored autophonic loudness for more continuous vocalisations (crescendi, decrescendi, and MDV) using adapted direct scaling methods. The results showed that sensorimotor mechanisms seem to be more important than hearing and room acoustics in autophonic loudness perception, which is consistent with previous research. Overall, this thesis showed that the room acoustics effect on the loudness of the singing voice needs to be assessed based on the communication scenario. This has relevance for voice analysis, loudness perception in general, room acoustics simulation, and vocal pedagogy.
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Frey, Johannes Daniel [Verfasser]. "Pre-attentive processing of room acoustics / Johannes Daniel Frey". Hamburg : Helmut-Schmidt-Universität, Bibliothek, 2017. http://d-nb.info/1131558847/34.
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Fazenda, Bruno M. "Perception of room modes in critical listening spaces". Thesis, University of Salford, 2004. http://usir.salford.ac.uk/1828/.
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Room modes are a recognised problem in small critical listening rooms and are known to cause colouration of sound reproduced within them. Investigations on the causes and solutions for this problem have been carried out for some time. Interest in the topic has extended to loudspeaker manufacturers who have mainly concentrated in developing methods for controlling the loudspeaker-room interaction in order to ameliorate low frequency reproduction. Compared to objective work on passive and active control methods, the study of the subjective perception of room resonances has been somewhat neglected. Available publications mostly concern the effects of single resonances, which are perhaps not fully representative of conditions as experienced in real rooms. A study into the subjective perception of room modes is presented. The experimental methodology employs psychoacoustic techniques to study the perception of factors such as modal distribution, and effects of resonances on single tones. Results show that the subjective perception of room modes is strongly affected by temporal issues, and that changes exerted merely on magnitude frequency response are detectable but not likely to remove the effects of resonances for all listeners. Furthermore, it is shown that a reduction of the modal Q-factor, associated with a reduction of decay rates, has a significant effect in decreasing the detection of resonances. Q-factor difference limen were evaluated for three reference decay characteristics corresponding to reference Q-factors of 30, 10 and 1. The limen were 6±2.8, 10±4.1 and 16±5.4 respectively, meaning that detection of changes to modal decay decreases with decreasing decay time. These results may be used to define more perceptually relevant design guidelines for critical listening environments, and indicate target criteria for control techniques used in room correction. The outcomes of this investigation will have repercussions on the design of better rooms for critical listening.
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Roper, Simon Edward. "A room acoustics measurement system using non-invasive microphone arrays". Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/891/.
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This thesis summarises research into adaptive room correction for small rooms and pre-recorded material, for example music of films. A measurement system to predict the sound at a remote location within a room, without a microphone at that location was investigated. This would allow the sound within a room to be adaptively manipulated to ensure that all listeners received optimum sound, therefore increasing their enjoyment. The solution presented used small microphone arrays, mounted on the room's walls. A unique geometry and processing system was designed, incorporating three processing stages, temporal, spatial and spectral. The temporal processing identifies individual reflection arrival times from the recorded data. Spatial processing estimates the angles of arrival of the reflections so that the three-dimensional coordinates of the reflections' origin can be calculated. The spectral processing then estimates the frequency response of the reflection. These estimates allow a mathematical model of the room to be calculated, based on the acoustic measurements made in the actual room. The model can then be used to predict the sound at different locations within the room. A simulated model of a room was produced to allow fast development of algorithms. Measurements in real rooms were then conducted and analysed to verify the theoretical models developed and to aid further development of the system. Results from these measurements and simulations, for each processing stage are presented.
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Denison, Michael Hunter. "Image Source Modeling of Time Reversal for Room Acoustics Applications". BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7449.
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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.
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Watson, John Lawrence, i not supplied. "An investigation into the identification of objective parameters correlating with the subjective functional performance of critical listening rooms". RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080218.092220.
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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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Seip, Clare Elizabeth. "Multipurpose room interior noise control for owners and facility managers". Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/502.
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Isebakke, Anders Kristoffer. "Edge Diffraction Implementation by Semi-Transparent Surfaces in Geometrical Room Acoustics". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13986.
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This report presents a potential method to efficiently implement edge diffraction from a noise barrier into geometrical room acoustic softwares. The modelling is based on semi-transparent surfaces, and the classic digital signal processing multipath transmission equation has been employed to describe in a mathematical term the presented method. The basic idea is to subdivide the noise barrier into a number of subareas, and then give each subarea an optimalized transmission coefficient for building the best possible output impulse response.To evaluate the proposed semi-transparent modelling, a Matlab simulation model of an infintite noise barrier case has been developed, and the corresponding simulations have been compared with the ideally correct solution. Accordingly, it is stated that there seems to be a clear positive potential in the proposed modelling technique. However, the results also reveal a somewhat instability in the modelling, which is expected to appear mainly for rare critical source and receiver positions.A main goal has been to develop a method that can easily be implemented in the existing calculation algorithms of today's commercial software developers. For verification, the proposed modelling has by discussion been associated with the often employed diffuse rain method. However, since no true implemenation in geometrical room acoustic software has been performed, further studies are required.To maintain efficiency and reliability, another desired outcome of the presented modelling has been that is should function for a general one-to-all source-receiver condition. Surely, the modelling seems to give fairly good results for symmetric source and receiver positions, but as the receiver is moved away from these symmetric conditions some unwanted errors occur, especially at higher frequencies.Main focus has been given to receiver positions located in the shadow zone, but some simulations and discussion has also been given to receiver positions located near the source-receiver sight line - at where direct sound energy contributions are also included and an interference pattern arises. To cope with this interference pattern, a polarity shift is proposed, which gives a clear improvement at low frequencies.One certainly interesting feature of the presented modelling technique is that it involves a broadband-based simulation method, which means that it gives the full frequency response by running only one simulation. Indeed, this is advantageous regarding calculation efficiency, but it does however also introduce some issues regarding a potential future software implementation - as the common case in geometrical room acoustics is to run individual octaveband-based simulations.
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SHTREPI, LOUENA. "Measurement traceability of sound scattering coefficient of diffusive surfaces used in room acoustics and virtual acoustical environments". Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2608163.
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The best concert halls take benefit not only from the basic room shape but also from the corrugations of the walls. These diffusive surfaces are responsible for energy mixing, energy extraction from geometrical paths, for filling gaps and increasing reflections density in the impulse response. Hence, performance spaces are characterized by a complex sound field, due to the presence of absorptive and diffusive surfaces. The acoustic properties of these surfaces are characterized based on laboratory standardized measurements. Despite this, no sufficiently satisfactory databases exist. Thus, acousticians and practitioners alike rely on guidelines and experience to make their design choices.
Based on this state of the art of diffusive surface design, the present work aims at giving more insight on their deployment by looking at the argument from a multidimensional point of view. First, it considers the estimation of the accuracy of the physical phenomenon measurements (only the random-incidence scattering coefficient has been considered), and further studies the effects of this accuracy on the objective room acoustic parameters, on the accuracy of simulation results and on perception. Knowing this interactions would give a measure of how much effort should be put into the acoustic characterization of diffusive surfaces and more freedom/ restrictions regarding the design of such surfaces could be determined.
In Chapter 2, the experimental results aimed at providing a useful insight into the accuracy of the measurement procedure prescribed in the ISO 17497-1:2004 standard. The unsolved aspects of the measurements set-up have been systematically investigated and their contribution to the random-incidence scattering coefficient values has been estimated. It was found that some of these aspects contribute significantly to the measurement accuracy.
In Chapter 3, in-situ evaluations of the acoustic effects that diffusive surfaces have on the objective room acoustic parameters have been investigated. To deepen such knowledge, acoustic measurements have been carried out in a variable-acoustic concert hall, the Espace de Projection, at the Institut de Recherche et Coordination Acoustique/Musique in Paris. The sensitivity of the sound field has been objectively investigated by observing the variation of the objective acoustic parameters, that is EDT, T30, C80, D50 and IACC, in either reflective and diffusive condition. It was found that some parameters are more affected by the degree of surface diffusivity, thus, its accuracy.
In Chapter 4 has been investigated objectively the sensitivity of a virtual room sound field to the scattering coefficients accuracy. Two different prediction models have been used to simulate the sound field within a fan-shaped hall. It was found that some simulated parameters are affected by the random-incidence scattering coefficient accuracy, i.e. uncertainties of input data, which are higher than a limit value, lead to less reliable simulation results.
In Chapter 5, an auditory experiment has been conducted to highlight some perceptual aspects regarding the use of diffusive surfaces in concert halls. These results provide more insight and help to understand whether listeners perceive the presence of diffusive surfaces, and how this perception is scattered throughout the audience area. Furthermore, the study is aimed at determining the objective measurements of a sound field which best correlate to the subject’s perception. This would give the measure of how much effort should be put into the determination of the diffusive properties of surfaces, and which could be the variables to relate in an analytic equation, which could readily express the effects of diffusion in room acoustic.
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Navarro, Ruiz Juan Miguel. "Discrete-time modelling of diffusion processes for room acoustics simulation and analysis". Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/14861.
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Esta tesis está centrada en el modelado de la acústica de salas en espacios cerrados mediante el uso de una ecuación de transferencia radiativa y una ecuación de difusión En este trabajo se investiga cómo a través de estos modelos teóricos se pueden simular el campo sonoro en espacios complejos. Recientemente, el modelo de la ecuación de fusión ha sido prppuesto para ser utilizado en el modelado de la acústica de salas con superficies que reflejan el sonido de forma totalmente difusa. Este enfoque del uso de la ecuación de la disusión de sido intensamente investigado en los últimos años, ya que proporciona una alta eficiencia y flexibilidad para simular las distribuciones del campo sonoro en diferentes tipos de salas; sin embargo, sólo se han realizado unas pocas investigaciones con el objetivo de indagar sobre la precisión y las limitaciones de este método alternativo.
Por lo tanto, en primer lugar se presenta un modelo basado en la ecuación de transferencia por radiación siendo meta principal el unificar una amplia gama de métodos geométricos de modelado de acústica de salas. Además, esta tesis está especialmente dedicada a establecer las bases y suposiciones que permitan obtener un modelo de difusión acústica como particularización del modelo de transferencia radiativa con el objetivo de conseguir una descripción clara y adecuada de sus ventajas y limitaciones desde el punto de vista teórico. Este trabajo permite enlazar directamente al modelo de la ecuación de difusión con el grupo de métodos de la acústica geométrica reforzando sus características y permitiendo una adecuada comparación con estos métodos ampliamente reconocidos.
Una vez realizado este análisis teórico, esta tesis también se dedica a cuestiones relativas a la implementación numérica del modelo acústico de la ecuación de difusión . En este trabajo, se modela el campo sonoro a través de esquemas en diferencias finitas. Los resultados de este estudio proporcionan soluciones simples y
practicas que muestran unos requerimientos computacionales bajos tanto
de consumo de memoria como de tiempo.Navarro Ruiz, JM. (2012). Discrete-time modelling of diffusion processes for room acoustics simulation and analysis [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14861
Palancia
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Carvalho, Vinícius Paggioli de. "Estudo e avaliação da acústica de home studios /". Ilha Solteira, 2019. http://hdl.handle.net/11449/190936.
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Orientador: João Antonio PereiraResumo: 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
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Downes, Julian. "The measurement of microphones in a reverberant room using a transient excitation method". Thesis, University of Surrey, 1985. http://epubs.surrey.ac.uk/847381/.
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A transient excitation method is described which allows the free field frequency and impulse responses of a microphone to be measured in a reverberant environment. The pressure transient generated by exciting a loudspeaker with a narrow voltage pulse is detected at a point in the loudspeaker's far field by the test microphone. A reference microphone, whose response is assumed flat over the frequency range of interest, is then substituted in exactly the same position and its response to the transient measured. The outputs of the two microphones are accurately sampled and deconvolved using a discrete Fourier transform technique to give the magnitude and phase parts of the test microphone's frequency response. Inverse transformation then gives the test microphone's response to an impulse of acoustic pressure propagating in the free field. Computed frequency and impulse responses are presented and the practical implementation and accuracy of the method discussed. The use of the method is illustrated by measurements of the free field frequency and impulse responses of several different microphones, including a 1" instrumentation microphone; free field correction curves for this microphone are also presented. Three digital analysis techniques are discussed and applied to some of the measured microphone responses where the discrete Hilbert transform is found to provide a method of calculating the phase part of the 1" microphone's frequency response over its useful frequency range without the ambiguities due to microphone misalignment inherent in the pulse method. The method is then used to measure the pressure which occurs at the centre of the flat end-face of a long cylinder when excited by a delta function of acoustic pressure from various incidence angles. A numerical time domain model is established which allows the impulse responses of this configuration to be computed. The interference effects caused by the proximity of two closely spaced instrumentation microphones in various orientations and configurations are also presented and discussed.
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Hamilton, Brian. "Finite difference and finite volume methods for wave-based modelling of room acoustics". Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/22940.
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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.
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Peacock, Gavin Robert. "The correction of room acoustics over a finite region using an artificial neural network". Thesis, University of Brighton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359075.
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Ozgenel, Caglar Firat. "Developing A Tool For Acoustical Performance Evaluation Throughout The Design". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614066/index.pdf.
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Performance of the buildings has always been a concern for the architects. With the enhancements in the technology, it is possible to measure, analyze and evaluate the performance of an architectural design before it is built via simulation tools developed. With the evaluation of the analysis performance of the concerned space can be upgraded if simulation tools are employed throughout the design process. However, even though the simulation tools are developed for the acoustical simulation and performance analysis, it is not always simple to integrate the simulation tools to whole design process because of both specific knowledge required for the usage of the tools and the nature of the acoustical simulation tools. Within the scope of the thesis, a simulation tool, which does not require advanced knowledge on acoustics and which provides rapid feedbacks about the performance of the design for the enhancement of the performance is developed using method of image sources.
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Jeong, Hyok. "Source and boundary conditions in finite difference time domain modelling of room acoustics". Thesis, University of Salford, 2010. http://usir.salford.ac.uk/26737/.
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This project deals with several issues on the use of Finite Difference Time Domain (FDTD) method for room acoustic simulation. The main features covered are: source implementation; modeling of frequency dependent boundary conditions; and modeling of arbitrary wall geometry and associated errors in stair-case approximations. A number of techniques for modeling frequency dependent boundary conditions in the FDTD method are presented and are validated against the Boundary Element Method (BEM). The results show that a Z-transform based multi-degree-offreedom model is the most effective for frequency dependent boundary conditions. Also of interest is that, when there is enough random incident waves onto the boundaries in the room, the energy based absorption coefficient can be used in conjunction with a minimum phase approach to obtain a suitable approximation for the time domain boundary condition in FDTD calculations. A thorough analysis on different source implementations is presented, and the cause of hard source problem is revealed. Based on the findings, a Time Limited Sine Modulated Gaussian Hard (TLSGH) source is developed that has the same characteristics of a transparent source, and yet retains the excellent computational efficiency of a hard source implementation. For a room with tilted boundary, results in this thesis show that standard FDTD using stair-case approximation can cause errors that exceed subjective difference limens in calculating room acoustic parameters. To solve this problem, the locally conformal boundary modelling method based on Dey-Mittra FDTD is extended for frequency dependent boundary conditions. Putting all together, FDTD method with TLSGH source and locally conformal frequency dependent boundary conditions shows remarkably good agreement compared to the more precise BEM. It is concluded that the techniques developed in this investigation significantly improve the effectiveness of FDTD in room acoustic simulations.
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Pike, C. D. "Timbral constancy and compensation for spectral distortion caused by loudspeaker and room acoustics". Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/809800/.
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On its path to the ear the spectral envelope of a sound is modified by transmission channels. These modifications can distort, or colour, sound timbre preventing recognition. Research by Olive et al. (1995) suggests that perceptual mechanisms remove spectral colouration caused by loudspeakers and rooms. This compensation is apparent when listening in the real-world but not in laboratory tests and may be a result of the longer time courses involved in real-world listening. Experiments conducted as part of this thesis confirm that compensation for loudspeaker/room colouration occurs using a real-world listening experimental paradigm and is perceptually moderate to large. This is partly caused by mechanisms that are sensitive to the time gaps between hearing different loudspeakers/rooms, common in real-world listening, and partly due to mechanisms that are not sensitive to these time gaps. A research process was set out to further investigate mechanisms behind the time-gap sensitive component of real-world compensation. A literature review of mechanisms that might explain this compensation was undertaken. A peripheral enhancement mechanism and a central spectral compensation mechanism cause compensation for spectral distortion caused by vocal tract (VT) characteristics in speech perception. These mechanisms are time-gap sensitive and were shown to have a number of features that mean they have the potential to cause the time-gap sensitive real-world compensation for loudspeakers and rooms. However, mechanisms that compensate for VT when listening to speech may not compensate for other channels when listening to non-speech. Laboratory tests were conducted to show that enhancement and spectral compensation also occur with non-speech sounds and therefore have the potential to contribute to any time-gap sensitive compensation for loudspeakers/rooms when listening to non-speech as well as speech. Therefore, these mechanisms can explain the real-world compensation seen in Olive et al.’s (1995) work and in real-world listening more generally. So far the specific mechanisms of real-world compensation have only been measured using laboratory studies. A framework is proposed for future work to confirm that these mechanisms explain real-world compensation using the real-world listening paradigm.
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VISENTIN, Chiara. "A NUMERICAL AND EXPERIMENTAL VALIDATION OF THE DIFFUSION EQUATION APPLIED TO ROOM ACOUSTICS". Doctoral thesis, Università degli studi di Ferrara, 2012. http://hdl.handle.net/11392/2389432.
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The recently developed room-acoustics diffusion model relies on the basic as-
sumptions of the Fick’s law of diffusion, relating the acoustic intensity and the
energy density inside a room, through a constant diffusion coefficient. This study
investigates the relationship between these two acoustic quantities in the station-
ary state, for the particular case of long rooms with different amounts of boundary
scattering, by means of numerical simulations and experimental measurements.
The numerical study was performed with a sound particle-tracing code. The ex-
periments consist in measurements inside the scale model of a long room, where a
three-dimensional Microflown➤ probe (calibrated and equalized with digital filters)
was employed to collect data in terms of pressure and axial velocity components.
Then, for each receiver position, the intensity and the energy density gradient were
derived. Both numerical and experimental results show that inside long rooms the
diffusion coefficient is not a constant but increases with the distance from the
source, with a slope depending on the scattering coefficient of the walls. This re-
sult implies that, for such long enclosures, the diffusion model should consider a
space-varying diffusion coefficient to be more consistent with real phenomena.
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Round, David Peter. "Application of DSP methods to sound reproduction". Thesis, Bangor University, 1996. https://research.bangor.ac.uk/portal/en/theses/application-of-dsp-methods-to-sound-reproduction(89e56009-ab09-4054-9a6b-e5181507a3f4).html.
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Courtis, N. J. "Some aspects of speech intelligibility enhancement with particular regard to adaptive filtering and room acoustics". Thesis, University of Hertfordshire, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356313.
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Thornock, Brian Trevor. "Comparison and Development of Methods for Measuring Directional Sound Arrivals in Rooms /". Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3183.pdf.
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Pospíšil, Vojtěch. "Kostel na Lesné". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265717.
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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.
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Zagala, Franck. "Simplified Acoustic Simulations and Virtual Acoustics : Contributions to Virtual Navigation for the Visually Impaired". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS254.
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Cette thèse s'inscrit dans projet RASPUTIN et s'intéresse au développement, à l'évaluation et à l'utilisation d'outils de simulation pour la réalité virtuelle acoustique dans le but d'aider les déficients visuels à préparer des navigations dans des lieux non-familiers. Alors que plusieurs outils d'assistance tels que des dispositifs de substitution sensorielle permettent de fournir des informations spatiales lors de navigations, une approche alternative consiste à concevoir un moteur de simulation et d'auralisation de l'acoustique d'un lieu en temps réel que les déficients visuels pourraient utiliser chez eux, leur permettant ainsi de naviguer virtuellement dans différents lieux, le tout dans des conditions contrôlées. Trois aspects de ce sujet sont abordés. La première partie se concentre sur la simulation et l'auralisation efficace de volumes couplés, qui sont présents dans de nombreux lieux d'intérêt pour la préparation à la navigation (mairies, hôpitaux ou musées) et où la simulation et l'auralisation peuvent s'avérer délicates. La deuxième partie s'intéresse à l'individualisation des fonctions de transfert relatives à la tête, une étape nécessaire pour délivrer une expérience auditive convaincante à chaque sujet. La dernière partie s'intéresse à certains aspects de la cognition de l'espace en fonction du paradigme utilisé pour l'exploration d'un lieuThis thesis takes place within the RASPUTIN project and focuses on the development, evaluation and use of immersive acoustic virtual reality simulation tools for the purpose of helping blind individuals prepare in-situ navigations in unfamiliar reverberant environments. While several assistive tools, such as sensory substitution devices, can provide spatial information during navigation, an alternative approach is to devise a real-time room acoustic simulation and auralization engine for use by blind individuals at home to enable them to virtually navigate in unfamiliar environments under controlled circumstances, hence building mental representations of these spaces prior to in-situ navigation. In this thesis, I tackle three aspects of this subject. The first part focuses on efficient simulations and auralizations of coupled volumes, which occur in many buildings of interest for navigation preparation (e.g. city halls, hospitals, or museums) and whose simulation and auralization can be challenging. The second part focuses on the individualization of head related transfer functions, which is a necessary step in providing individualized and convincing auditory experiences. Finally, the last part investigates some aspects of the space cognition following use of different learning paradigms, such as tactile maps
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Jesus, Ana Sofia Dâmaso Mateus de. "Comportamento acústico de salas para o ensino musical no Algarve: a perspetiva dos vários intervenientes". Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/14556.
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O comportamento acústico de salas para música é um tema que tem vindo a destacar-se ao nível da engenharia nas últimas décadas. Todavia, no que diz respeito a questões musicais mais específicas, o mesmo não tem vindo acontecer. Desta forma, optou-se por realizar um estudo sobre a perspetiva dos professores de música relativamente à qualidade acústica das salas onde lecionam. Estudo esse que pretendeu aferir as características favoráveis a este tipo de salas para que na opinião dos professores privilegiassem o ensino musical.
Mediante a pouca bibliografia existente, a investigação direcionou-se para uma pesquisa exploratória e descritiva. A recolha de dados foi feita através da observação e de inquéritos-questionários aos professores. Enquanto, o tratamento de dados foi estatístico e descritivo.
Contudo, as diferentes sensações sonoras e os poucos conhecimentos acústicos dos professores não permitiram alcançar o objetivo principal de forma clara e precisa. No entanto, conseguiu-se verificar quais as salas existentes que melhor e pior se adaptam ao ensino musical e quais as suas tendências; ABSTRACT:
ACOUSTIC BEHAVIOR OF ROOMS FOR MUSICAL EDUCATION IN ALGARVE
The perspective of the various stakeholders
The acoustic behavior of rooms for music is a topic that has come to prominence in engineering over the past decades. However, with regard to more specific musical issues it has not been happening . Thus it was decided to conduct a study on the prospect of music teachers regarding the acoustic quality of the rooms where they teach. This study sought to assess the favorable characteristics for this type of rooms which in the opinion of teachers favoring musical teaching.
By little existing literature, research directed to an exploratory and descriptive research. Data collection was done through observation and surveys, questionnaires to teachers. While treatment data was statistical and descriptive.
However, different sound sensations and the few acoustic knowledge of teachers not allowed to reach the main goal of clearly and precisely. However, we could note that the existing rooms that best and worst fits to music teaching and what their trends.
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Xu, Buye. "Generalized Acoustic Energy Density and Its Applications". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2339.
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The properties of acoustic kinetic energy density and total energy density of sound fields in lightly damped enclosures have been explored thoroughly in the literature. Their increased spatial uniformity makes them more favorable measurement quantities for various applications than acoustic potential energy density (or squared pressure), which is most often used. In this dissertation, a new acoustic energy quantity, the generalized acoustic energy density (GED), will be introduced. It is defined by introducing weighting factors, α and 1 − α, in the formulation of total acoustic energy density. With the additional degree of freedom, the GED can conform to the traditional acoustic energy density quantities, or be optimized for different applications. The properties and applications of the GED are explored in this dissertation. For enclosed sound fields, it was found that GED with α = 1/4 is spatially more uniform than the acoustic potential energy density, acoustic kinetic energy density, and the total acoustic energy density, which makes it a more favorable measurement quantity than those traditional acoustic energy density quantities for many indoor measurement applications. For some other applications, such as active noise control in diffuse field, different values of α may be considered superior. The numerical verifications in this research are mainly based on a hybrid modal expansion developed for this work, which combines the free field Green's function and a modal expansion. The enclosed sound field is separated into the direct field and reverberant field, which have been treated together in traditional modal analysis. Studies on a point source in rectangular enclosures show that the hybrid modal expansion converges notably faster than the traditional modal expansions, especially in the region near the source, and introduces much smaller errors with a limited number of modes. The hybrid modal expansion can be easily applied to complex sound sources if the free field responses of the sources are known. Damped boundaries are also considered in this dissertation, and a set of modified modal functions is introduced, which is shown to be suitable for many damped boundary conditions.
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Marros, Fernanda. "CARACETERIZAÇÃO ACÚSTICA DE SALAS PARA PRÁTICA E ENSINO MUSICAL". Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/7771.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe musician needs to properly perceive the sound in rooms where it operates, either in an environment designed to be performed or to studying and practice music. For this, it is necessary that these sites are acoustically appropriate, enabling the development and enhancement of musical sound perception. In this study six classrooms of the music school of UFSM were characterized by acoustic impulse response measurements and computer simulation, and considered the user s feedback through questionnaires. The questionnaires enabled to understand the preferences of students and music teachers regarding the acoustic quality of a total of twenty rooms for music practice and teaching. Three study rooms and three collective classrooms were the most cited out of those available for the course, which were evaluated by acoustic impulse response, resulting in achieving specified objectives of the main parameters to assess the acoustic quality of rooms by ISO 3382: 2009. The information provided by the musicians proved to be coherent with the measurement data, as the rooms considered dry had presented reverberation times around 0.4 s, and the rooms considered reverberants had reverberation times (RT) around 1.5 s. The six rooms were characterized as clear and well defined rooms, with values for Clarity ranging between 1.0 and 2.0 dB for live rooms and around 22 dB for dry rooms. The definition has remained above 43% for all rooms with Central Time below 50 ms for rooms of greater clarity and less reverberant, and above 90 ms for the live rooms. In general, most rooms were considered weak in relation to acoustic conditioning, and only two out of twenty rooms were considered adequate by most musicians, without receiving considerable negative criticism, being one a study room with a volume of 79.9 m³ and TR equal to 0.4 seconds, and the other a collective classroom with a volume of 327.85 m³ and TR equal to 1.6 s. The computer simulation was efficient for the prediction of the acoustic behavior of the rooms in study and the data obtained in the simulations were compared to the just noticeable difference (JND) for acoustic parameters investigated (T30, EDT, C80, D50 and Ts). A good correlation was observed between measured and simulated data, particularly for parameters related to noise energy in the frequency range from 63 to 8.000 Hz.
O músico necessita perceber adequadamente o som nos recintos onde atua, seja em ambientes destinados à performance, seja em ambientes destinados ao estudo e prática musical. Para que isto seja possível é necessário que estes locais estejam acusticamente adequados, permitindo o desenvolvimento e aprimoramento da percepção sonora musical. No presente trabalho seis salas de aula do curso de graduação em Música da UFSM foram caracterizadas através de medições acústicas da resposta impulso e de simulação computacional, além de considerar a opinião dos usuários mediante questionários. Os questionários aplicados permitiram compreender as preferências dos estudantes e professores de música no que se refere à qualidade acústica de um total de vinte salas para prática e ensino musical. Três salas de estudo e três salas de aula coletiva foram as mais citadas dentre as disponíveis para o curso, as quais foram avaliadas acusticamente através da resposta impulso, resultando na obtenção dos principais parâmetros objetivos especificados para a avaliação da qualidade acústica de salas pela norma ISO 3382: 2009. As informações fornecidas pelos músicos se mostraram coerentes com os dados das medições, de forma que e as salas consideradas secas apresentaram tempos de reverberação (TR) em torno de 0,4 s, e as salas consideradas reverberantes apresentaram tempos de reverberação em torno de 1,5 s. As seis salas se caracterizaram como salas claras e definidas, com valores para Clareza variando entre 1,0 e 2,0 dB para as salas vivas e em torno de 22 dB para as salas secas. A Definição se manteve acima de 43% para todas as salas, com Tempo Central abaixo de 50 ms para salas mais claras e menos reverberantes e acima de 90 ms para as salas mais vivas. Em geral, a maioria das salas apresenta deficiências em relação ao condicionamento acústico, sendo que somente duas das vinte salas foram consideradas adequadas pela maioria dos músicos, sem receber críticas negativas consideráveis, sendo uma sala de estudo com volume de 79,9 m³ e TR igual a 0,4 s, e uma sala de aula coletiva com volume de 327,85 m³ e TR igual a 1,6 s. A simulação computacional se mostrou eficiente para predição do comportamento acústico das salas em questão e os dados obtidos nas simulações foram comparados em relação à diferença no limite do observável (JND) para os parâmetros acústicos investigados (T30, EDT, C80, D50 e Ts). Uma boa correlação foi observada entre dados medidos e simulados, principalmente para os parâmetros relacionados à energia sonora na faixa de frequência de 63 a 8.000 Hz.
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Nestoras, Christos. "The assessment of speech intelligibility in room acoustics for efficient application in computer modelling and improved enclosed spaces". Thesis, London South Bank University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618686.
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Schutte, Michael [Verfasser], i Benedikt [Akademischer Betreuer] Grothe. "Aspects of room acoustics, vision and motion in the human auditory perception of space / Michael Schutte ; Betreuer: Benedikt Grothe". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1241963762/34.
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Santos, Marta Antão Rodrigues dos. "Qualidade acústica de escolas de música do Algarve: análise e proposta de medidas de melhoria". Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/11823.
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As salas de aula para prática musical são locais em que a exigência de conforto acústico é essencial, permitindo assim, garantir uma boa sonoridade e perceção de todas as gamas sonoras emitidas pelos instrumentos musicais. Este trabalho visa a avaliação acústica de salas de aula de oito escolas de música do Algarve (Academia de Música de Lagos, Conservatório de Portimão Joly Braga Santos, Conservatório de Música de Lagoa, Conservatório de Música de Albufeira, Conservatório Regional do Algarve Maria Campina, Conservatório de Música de Olhão, Academia de Música de Tavira e Conservatório Regional de Vila Real de St.º António). Em cada escola foram apenas avaliadas duas salas de aula que foram eleitas através de um Questionário realizado aos alunos e professores das escolas. Nessas mesmas salas foram medidos vários parâmetros acústicos tais como o Tempo de Reverberação, Clareza, Definição, Tempo de Decaimento Inicial, Tempo Central, Fator de Força e Ruído de Fundo. Os resultados obtidos através de medições efetuadas foram analisados de acordo com a Norma EN ISO 3382 – 1 Acoustics - Measurement of room acoustic parameters e no fim foram propostas medidas para a melhoria da qualidade acústica das salas; Abstract:
The classrooms are places for musical practice in which the requirement of acoustic comfort is essential, thus, ensuring a good perception of sound and all sound ranges issued by musical instruments. This paper aims to review the acoustics of classrooms eight music schools in the Algarve (Lagos Academy of Music, Portimão Conservatory of Joly Braga Santos, Lagoa Conservatory of Music, Albufeira Conservatory of Music, Algarve Regional Conservatory Maria Campina, Olhão Conservatory of Music, Tavira Academy of Music and Regional Conservatory of Vila Real de St. Antonio). In each school were only evaluated two classrooms that were elected through a questionnaire conducted among students and teachers of the schools. In these same rooms were measured various acoustic parameters such as Reverberation Time, Clarity, Definition, Early Decay Time, Centre Time, Sound Strength and Background Noise. The results obtained from measurements taken were analyzed in accordance with EN ISO 3382-1 Acoustics - Measurement of room acoustic parameters and measures were proposed in order to improve the acoustic quality of rooms.
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Wahlborn, Felicia. "Rum för musik". Thesis, KTH, Arkitektur, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146755.
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Detta examensarbete behandlar rumsakustik som en viktig del i skapandet av en arkitektur för framförande av musik, samt upplevelsen av ljud. Projektet bygger på en idé att skapa nya möjligheter att skapa och framföra musik för musiker, vars arbete ofta begränsas av lokalbrist eller av olika föreningars intresseområden. Idén har utvecklats till en hybrid mellan ett nytt musikmuseum och ”Musikplatsen” - en plats för skapande och framförande av musik med liten publik. Musikplatsen blir en del av det nya musikmuseets program för att skapa nya samarbeten och ekonomisk hållbarhet. Projektet är placerat mellan Gröndal och Lövholmen och knyter samman områdenas olika strukturer. Därför spelar detta projekt även en stadsbyggnadsmässig roll som kulturinstitution i en möjlig framtida exploatering av Lövholmens industriområde. I museidelen finns fokus på god utställningsmiljö för olika typer av utställningar i enlighet med övergripande akustiska och arkitektoniska strategier. I projektet finns även en fördjupning inom området rumsakustik vilket har resulterat i särskilt fokus på akustik i designen av byggnadens största rum, - en konsertsalong med 700 platser för akustisk musik. Designprocessen har framskridit på ett kontrollerat sätt via matematiska beräkningar för att nå djupare förståelse inom rumsakustikens komplexitet.This diploma project investigates room acoustics as a crucial part in developing an architecture for music performance and the experience of sound. The origin of the project comes from an idea to facilitate the constrained work situation of local musicians in the Stockholm region. The idea has been developed into a hybrid between a new music museum and a place for music creation and performance. The project is situated at Lövholmen/Gröndal connecting two totally different areas together along the existing main street. Thus the project also plays a part in a possible future urban development of the industrial area of Lövholmen. The museum parts have focus on interior environment in terms of exhibition spaces for different content, haptic and acoustic experience. Within this project there has been a deep research on room acoustics that has resulted in special focus while designing the largest space, a concert hall for an audience of 700. The design process has proceeded in a controlled way along with mathematical calculations to create a final design on a controlled basis to gain deeper understanding of fundamental parts in the field of room acoustics.
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Kowalczyk, K. "Boundary and medium modelling using compact finite difference schemes in simulations of room acoustics for audio and architectural design applications". Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517381.
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Brum, Cristhian Moreira. "SIMULAÇÃO ACÚSTICA DE SALAS DE AULA EM ESCOLAS DE EDUCAÇÃO BÁSICA: UMA PROPOSTA TIPOLÓGICA PARA PRÁTICA MUSICAL". Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/7813.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe study of room acoustics is linked to the importance of sound inside a room, so the architectural characteristics of the internal space determine the acoustic behavior. To get better acoustics of a room there are computational methods that simulate the acoustic behavior of a room before his execution, providing the prediction of the simulated environment behavior from the acoustic point of view. The acoustic parameters of the resulting acoustic simulations as Reverberation Time, Initial Decay Time, Clarity, Sharpness and Speech Transmission Index, are responsible for identifying the acoustic conditions of the geometric model of a classroom. This geometric model used as sample classrooms of different types of municipal schools in Santa Maria - RS, with the aim of developing a classroom typology for the music teaching from virtual acoustic models using computing simulation. Geometric models of classrooms for teaching music were developed using as input data, dimensions, shapes and elements usually used in these environments and developed representative virtual acoustic models these virtual classrooms, in which were measured acoustic parameters related to the reverberation time from the impulse response of the acoustic models of virtual rooms. We analyzed the experimental results and simulated with and without furniture for the acoustic parameters, and these comparisons were related to the values of JND (Just Noticeable Difference) near the standard tolerance according to ISO 3382/2009 with normalized values of 500 Hz to 1000 Hz. A geometric study was developed based on Bolt (1946) which defined the appropriate geometric measures of the room. Thus, a functional typology was originated which meets the architectural acoustic requirements and the initial proposal of presenting a music classroom typology providing an environment with acoustic quality, according to Law number 11.769/2008 that inserts education music in schools on a mandatory basis.
O estudo da acústica de salas está vinculado à importância do som dentro de um recinto, logo, as características arquitetônicas do espaço interno determinam seu comportamento acústico. Para buscar melhores condições acústicas de um recinto disponibilizam-se métodos computacionais que simulem o comportamento acústico de uma sala, antes de sua execução, proporcionando a previsão de comportamento do ambiente simulado do ponto de vista acústico. Os parâmetros acústicos resultantes das simulações acústicas, como: Tempo de Reverberação, Tempo de Decaimento Inicial, Clareza, Definição e o Índice de Transmissão da Fala são responsáveis pela identificação das condições acústicas do modelo geométrico de uma sala de aula. Este modelo geométrico utilizou como amostra as salas de aula das diferentes tipologias de escolas da rede estadual de educação de Santa Maria - RS, com o objetivo de desenvolver uma tipologia de sala de aula, para o ensino da música, a partir de modelos acústicos virtuais utilizando-se simulação computacional. Foram desenvolvidos modelos geométricos de salas de aula para o ensino da música utilizando-se como dados de entrada, dimensões, formatos e elementos, usualmente utilizados nestes ambientes, e desenvolvidos modelos acústicos virtuais representativos destas salas, aos quais foi feita uma avaliação dos parâmetros acústicos relacionados ao tempo de reverberação, partindo-se da resposta impulso dos modelos acústicos virtuais das salas. Foram analisados resultados experimentais e simulados na situação sem mobília e com mobília, para os parâmetros acústicos, e essas comparações foram relacionadas com os valores de JND (em inglês Just Noticeable Difference) padronizadas as margens de tolerância, de acordo com a ISO 3382/2009, com valores normalizados de 500 Hz a 1000 Hz. Também foi desenvolvido um estudo geométrico, a partir de Bolt (1946), que definiu as medidas geométricas adequadas da sala. Com isto, originou-se uma tipologia funcional, observando as exigências acústicas arquitetônicas, cumprindo a proposta inicial de apresentar uma tipologia de sala de aula, para a música, a fim de proporcionar um ambiente com qualidade acústica, atendendo a Lei nº 11.769/2008, que insere o ensino da música nas escolas, de forma obrigatória.
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Johansson, Anders. "Acoustic Sound Source Localisation and Tracking : in Indoor Environments". Doctoral thesis, Blekinge Tekniska Högskola [bth.se], School of Engineering - Dept. of Signal Processing, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00401.
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With advances in micro-electronic complexity and fabrication, sophisticated algorithms for source localisation and tracking can now be deployed in cost sensitive appliances for both consumer and commercial markets. As a result, such algorithms are becoming ubiquitous elements of contemporary communication, robotics and surveillance systems. Two of the main requirements of acoustic localisation and tracking algorithms are robustness to acoustic disturbances (to maximise localisation accuracy), and low computational complexity (to minimise power-dissipation and cost of hardware components). The research presented in this thesis covers both advances in robustness and in computational complexity for acoustic source localisation and tracking algorithms. This thesis also presents advances in modelling of sound propagation in indoor environments; a key to the development and evaluation of acoustic localisation and tracking algorithms. As an advance in the field of tracking, this thesis also presents a new method for tracking human speakers in which the problem of the discontinuous nature of human speech is addressed using a new state-space filter based algorithm which incorporates a voice activity detector. The algorithm is shown to achieve superior tracking performance compared to traditional approaches. Furthermore, the algorithm is implemented in a real-time system using a method which yields a low computational complexity. Additionally, a new method is presented for optimising the parameters for the dynamics model used in a state-space filter. The method features an evolution strategy optimisation algorithm to identify the optimum dynamics’ model parameters. Results show that the algorithm is capable of real-time online identification of optimum parameters for different types of dynamics models without access to ground-truth data. Finally, two new localisation algorithms are developed and compared to older well established methods. In this context an analytic analysis of noise and room reverberation is conducted, considering its influence on the performance of localisation algorithms. The algorithms are implemented in a real-time system and are evaluated with respect to robustness and computational complexity. Results show that the new algorithms outperform their older counterparts, both with regards to computational complexity, and robustness to reverberation and background noise. The field of acoustic modelling is advanced in a new method for predicting the energy decay in impulse responses simulated using the image source method. The new method is applied to the problem of designing synthetic rooms with a defined reverberation time, and is compared to several well established methods for reverberation time prediction. This comparison reveals that the new method is the most accurate.
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Norberg, Hanna. "Utredning av Umeå universitets gemensamma föreläsningssalars ljudmiljöer och rumsakustik : Med fokus på taluppfattbarhet, efterklangstid samt installationsbuller". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-144182.
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The purpose of this report was to investigate the sound environments in lecture halls at Umeå University and to assess to whether the sound environments in these lecture halls are satisfactory and whether have good speech intelligibility or not. Based on a web survey, a number of lecture halls were selected for this investigation, namely Hörsal A, Hörsal C, N280, KB.F3.01, Ma121, KB.E3.01, N340 and N335. Assessing room acoustics includes many relevant parameters, therefore a delimitation has been made. Only installation noise, reverberation time and speech intelligibility have been investigated. The methods followed established Swedish standards i.e SS-EN ISO 16032:2004 for installation noise,” integrated impulse response method” SS-EN ISO 3382:2:2008/AC:2009 for reverberation time and direct FULL STI (speech transmission index) IEC 60268-16:2011 for speech intelligibility. An ocular inspection was carried out of all the selected lecture halls. The result from the STI test showed that all the lecture halls except for Hörsal A have a good speech intelligibility, if the audience has normal hearing and they are listening to a lecture in their native language. In Hörsal A there are three measuring positions that fails to achieve the threshold for good speech intelligibility. The conclusion for all of the measurements that has been made are that Ma121 and KB.E3.01 has a satisfactory sound environment and that Hörsal A, Hörsal C, N280, KB.F3.01, N340 and N335 need actions to improve their sound environment so they can fulfil the benchmarks in Swedish public health authority regulations in FoHMFS 2014:13 and/or SS 25268:2007.
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Paliesek, Jakub. "Vliv akustiky prostředí na úspěšnost rozpoznávače řeči". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2021. http://www.nusl.cz/ntk/nusl-445549.
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This diploma thesis deals with impact of room acoustics on automatic speech recognition (ASR) accuracy. Experiments were evaluated on speech corpus LibriSpeech and database of impulse responses and noise called ReverbDB. Used ASRs were based on Mini LibriSpeech recipe for Kaldi. First it was examined how well can ASR learn to transcribe in selected environments by using the same acoustic conditions during training and testing. Next, experiments were carried out with modifications of ASR architecture in order to achieve better robustness against new conditions by using methods for adapation to room acoustics - r-vectors and i-vectors. It was shown that recently proposed method of r-vectors is beneficial even when using real impulse responses for data augmentation.