Since its inception in 2004, nested sampling has been used in acoustics applications. This work a... more Since its inception in 2004, nested sampling has been used in acoustics applications. This work applies nested sampling within a Bayesian framework to the detection and localization of sound sources using a spherical microphone array. Beyond an existing work, this source localization task relies on spherical harmonics to establish parametric models that distinguish the background sound environment from the presence of sound sources. Upon a positive detection, the parametric models are also involved to estimate an unknown number of potentially multiple sound sources. For the purpose of source detection, a no-source scenario needs to be considered in addition to the presence of at least one sound source. Specifically, the spherical microphone array senses the sound environment. The acoustic data are analyzed via spherical Fourier transforms using a Bayesian model comparison of two different models accounting for the absence and presence of sound sources for the source detection. Upon a positive detection, potentially multiple source models are involved to analyze direction of arrivals (DoAs) using Bayesian model selection and parameter estimation for the sound source enumeration and localization. These are two levels (enumeration and localization) of inferential estimations necessary to correctly localize potentially multiple sound sources. This paper discusses an efficient implementation of the nested sampling algorithm applied to the sound source detection and localization within the Bayesian framework.
Finite-difference methods are becoming increasingly popular in the acoustics community, and the i... more Finite-difference methods are becoming increasingly popular in the acoustics community, and the importance of higherorder methods has been acknowledged. However, the choice of an appropriate source for these methods has been largely overlooked in the acoustics literature. Published literature acknowledges the importance of selecting a continuous function, but it does not consider whether the function's derivatives are also continuous. The error resulting from discontinuous higher-order derivatives can contaminate a finite difference simulation with unnecessary, low-order, dispersive error, diminishing the order of accuracy of the overall scheme. This problem is discussed in the context of simple, wave equation solvers of various order with a variety of sources.
Journal of the Acoustical Society of America, Nov 1, 2019
Reverberation time measurements were conducted in the 21-lane indoor firing range at Wright Patte... more Reverberation time measurements were conducted in the 21-lane indoor firing range at Wright Patterson Air Force Base. Long reverberation times resulted in poor speech transmission indices (STI) which required acoustical treatments within the range. After treatment, reverberation times were significantly reduced and STI was dramatically enhanced. Standard Sabine and Eyring models failed to accurately predict the reverberation times. A computer simulation of the range was developed to predict room acoustic conditions and auralize speech performance for perceptual evaluation in the range.
In virtual auditory display via headphone, the unwanted spectral transformation (i.e., Headphone-... more In virtual auditory display via headphone, the unwanted spectral transformation (i.e., Headphone-to-ear-canal transfer functions, HpTFs) introduced by unflat headphone response and the acoustical coupling between the headphone transducer and the external ear should be eliminated in order to ensure authentic reproduction [1,2]. Since each person owns a unique dimension of external ear (especially pinna), HpTFs are individual-dependent. Acoustical measurement is a common way to obtain individual HpTFs. In practice, however, measurement errors from headphone and microphone placements are unavoidable. Moreover, measurement errors and individual characteristics are often mixed together, especially at high frequencies where both the measurement errors and the individual characteristics are obvious.
The Journal of the Acoustical Society of America, 2021
The acoustic diffusion equation model has been applied within a wide range of enclosure types to ... more The acoustic diffusion equation model has been applied within a wide range of enclosure types to simulate diffuse sound fields. Recently, focus has been drawn to its applicability in reverberation chambers to simulate sound fields among a heterogeneous distribution of absorbing materials, particularly those that are highly absorptive. Where quasi-diffuse or non-diffuse sound fields are generated in the presence of highly absorptive material, the acoustic diffusion equation model has convenient capabilities to simulate sound energy flow. Furthermore, it has continued to show promise in characterizing the absorption coefficients of sound absorbing material. Challenges for reproducibility in reverberation room measurements have been well-documented and where traditional chamber-based measurement have shown to be inconsistent, this work will evaluate the acoustic diffusion equation model’s suitability as an alternative and accurate method to characterize absorption coefficients.
The Journal of the Acoustical Society of America, 2019
This study investigates reliable models and methods to be applied in sound field analysis of mult... more This study investigates reliable models and methods to be applied in sound field analysis of multi-domain structures. The case structures are two monuments, namely, Süleymaniye Mosque and Hagia Sophia in İstanbul. These are both multi-volume spaces with many smaller sub-volumes coupled to each other by coupling apertures in form of arches. A key concern of the study is to examine energy flow decays and understand the mechanism of multi-slope sound energy decays. The methodology involves diffusion equation model (DEM) application in a finite-element scheme for sound energy flow analysis. Energy flow decays, energy flow dips, and spatial flow vectors are examined for single versus multi-domain DEM solutions. It is concluded that specification of different domains with individual diffusion coefficients is a critical setting such that, if not assigned correctly, may mislead the results. The energy flow vector analysis has enabled us to comprehend the architectural features in relation t...
The key concern of this study is to discuss the reliable acoustical metrics for analyzing particu... more The key concern of this study is to discuss the reliable acoustical metrics for analyzing particular sound fields within monumental multi-domed sacred spaces with an emphasis on multiple sound energy decay formation. The potential of such structures in featuring non-exponential sound energy decay characteristics necessitates new formulation of sound decay indicators in understanding of their sound fields. The early and late energy decay components within non-exponential sound energy decays can have a unique contribution to the interior acoustic quality. These acoustical features can also provide the functional and spiritual acoustical needs of monumental sacred spaces. Süleymaniye Mosque and Hagia Sophia, two major monuments of Istanbul World Heritage Site, are examined in this regard. Field measurements are the main method of data collection. Over collected room impulse responses, relevant acoustical predictors including decay rates and decay times are computed by applying Bayesian decay parameter estimation. Analysis results disclose double or triple decay formations in both structures. Authors argue that, the detection of multiple sound energy decays in analyzed structures sets out a new vision for room acoustics studies of sacred spaces and for multi-domed monuments. Thus, implementation of new metrics, namely multiple slope decay parameters to replace classical room acoustics indicators, is recommended and discussed in light of the outcomes of this study. Acoustical indicators • Multiple sound energy decay • Bayesian analysis • Sacred space acoustics • Süleymaniye Mosque • Hagia Sophia in İstanbul B Zühre Sü Gül
In this work, a diffusion equation model (DEM) is applied to a room acoustics case for in-depth s... more In this work, a diffusion equation model (DEM) is applied to a room acoustics case for in-depth sound field analysis. Background of the theory, the governing and boundary equations specifically applicable to this study are presented. A three-dimensional geometric model of a monumental worship space is composed. The DEM is solved over this model in a finite element framework to obtain sound energy densities. The sound field within the monument is numerically assessed; spatial sound energy distributions and flow vector analysis are conducted through the time-dependent DEM solutions.
The Journal of the Acoustical Society of America, 2013
Design for acoustic performance in an interior fluid domain requires accurate description of boun... more Design for acoustic performance in an interior fluid domain requires accurate description of boundary materials' specific acoustic impedance. The standard approach for the estimation of this material characteristic is the two-microphone, impedance-tube method. Modifications to the processing of the sampled acoustic field have been proposed to allow for more general test geometries. While analytical methods may be applied to a small class of ideal geometries, numerical methods provide greater geometric flexibility. In general, solutions to the wave equation forward problem are found from boundary element, finite element, or finite difference methods. The inverse problem of parameter estimation is solved by evaluating accuracy of prediction of the acoustic field for given distributions of the specific acoustic impedance parameter against observed data. In this presentation a Bayesian-network sampling approach is used to estimate specific acoustic impedance of a micro-perforated pa...
The Journal of the Acoustical Society of America, 2013
Nested sampling is increasingly being used to calculate the evidence for competing models in Baye... more Nested sampling is increasingly being used to calculate the evidence for competing models in Bayesian model comparison problems arising in acoustics applications. Use of nested sampling offers advantages in robustness over alternative methods of evidence calculation and enables evidence calculation for models with many parameters. The most challenging aspect of implementing nested sampling is sampling from the prior for the parameters constrained by a threshold likelihood value. For models with just a few parameters, sampling from the constrained prior can be accomplished with a simple Monte Carlo algorithm implementing a random walk, however, this simple method is inefficient and fails as the number of model parameters increases. John Skilling, the originator of nested sampling, has proposed the “Galilean” Monte Carlo method for efficiently sampling from the constrained prior when there are many parameters. Unlike the random walk method, the Galilean Monte Carlo method moves sample...
The Journal of the Acoustical Society of America, 2013
Markov Chain Monte Carlo (MCMC) algorithms for Bayesian model selection have been increasingly ap... more Markov Chain Monte Carlo (MCMC) algorithms for Bayesian model selection have been increasingly applied to acoustics applications. One of challenging tasks required in Bayesian model selection is the exploration of high-dimensional multi-variate spaces such that a key quantity, termed the Bayesian evidence, can be estimated in order to rank a set of competing models. This work presents a class of energy-based MCMC algorithms specifically designed to estimate the Bayesian evidence. As illustrative examples, the energy-based MCMC algorithms are applied to the problem of filter design as used in human head-related transfer functions and in acoustic impedance boundaries within the finite-difference time-domain framework for room-acoustics simulations.
Journal of the Acoustical Society of America, Jun 1, 2018
Coprime microphone arrays use sparse sensing to achieve greater degrees of freedom, while the cop... more Coprime microphone arrays use sparse sensing to achieve greater degrees of freedom, while the coprimality of the microphone subarrays help resolve grating lobe ambiguities. The result is a narrow beam at frequencies higher than the spatial Nyquist limit allows, with residual side lobes arising from aliasing. These side lobes can be mitigated when observing broadband sources, as shown by Bush and Xiang [J. Acoust. Soc. Am. 138, 447-456 (2015)]. Peak positions may indicate directions of arrival in this case; however, one must first ask how many sources are present. In answering this question, this work employs a model describing scenes with potentially multiple concurrent sound sources. Bayesian inference is used to first select which model the data prefer from competing models before estimating model parameters, including the particular source locations. The model is a linear combination of Laplace distribution functions (one per sound source). The likelihood function is explored by a Markov Chain Monte Carlo method called nested sampling in order to evaluate Bayesian evidence for each model. These values increase monotonically with model complexity; however, diminished returns are penalized via an implementation of Occam's razor.
Plane-wave decompositions, whereby a measured sound field is described as a superposition of plan... more Plane-wave decompositions, whereby a measured sound field is described as a superposition of plane waves, are central to many applications in acoustics and audio engineering. This letter applies a Bayesian probabilistic inference framework to the plane wave decomposition problem and examines the Deviance Information Criterion (DIC) for selecting the optimum number of waves in the decomposition. The framework learns the model directly from the data and, as such, adapts to the wavefield under study. The DIC is applied to data measured in two reverberant sound fields (highly-reverberant and lightly-damped) to determine the simplest models providing the preferred fit to the data.
Acoustic surface admittance/impedance at domain boundaries is essential for wave-based acoustic s... more Acoustic surface admittance/impedance at domain boundaries is essential for wave-based acoustic simulations. This work applies two levels of Bayesian inference to estimate the order and the parameter values of the multipole admittance model. The frequency-dependent acoustic admittance is experimentally measured. Incorporating the maximum entropy strategy, the unified Bayesian framework is applied to the multipole approximation. Analysis results demonstrate that multipole model-based Bayesian inference is well suited to estimating the arbitrary frequency-dependent boundary condition within a wave-based simulation framework.
If one of the goals of computational room acoustics is auralization, then one must also define ph... more If one of the goals of computational room acoustics is auralization, then one must also define physical accuracy criteria in terms of what is audible. Some types of errors, such as neglect of low-frequency modes and edge diffraction, may be so clearly audible that sophisticated psychoacoustic evaluation is sometimes unnecessary. On the other hand, computations of surface scattering may have errors on the order of 1-3 dB. one may ask when such errors are aurally significant. For example, small spectral changes audible for single scattering from a rough surface may not be audible in a room impulse response, depending on the density and decay rate of the reflections (and the corresponding degree of comb-filter effects), the similarity to frequency spectra of other reflections, the effects on the early or late parts of the impulse response, and the input signal that is used in a given auralization. This paper examines various room scattering computations and describes subjective methods for evaluating them in terms of aural adequacy. The tests for aural-adequacy employ time-frequency analysis, ABX listening tests, and multi-dimensional analysis of listening experiments to evaluate differences in numerical results.
The Journal of the Acoustical Society of America, 2013
Some recent concert hall designs have incorporated coupled reverberation chambers to the main hal... more Some recent concert hall designs have incorporated coupled reverberation chambers to the main hall that have stimulated a range of research activities in architectural acoustics. The coupling apertures between two or more coupled-volume systems are of central importance for sound propagation and sound energy decays throughout the coupled-volume systems. In addition, positions of sound sources and receivers relative to the aperture also have a profound influence on the sound energy distributions and decays. This work investigates the effect of aperture size on the behavior of coupled-volume systems using both acoustic scale-models and diffusion equation models. In these physical and numerical models, the sound source and receiver positions relative to the aperture are also investigated. Through systematic comparisons between results achieved from both physical scale models and numerical models, this work reveals valid ranges and limitations of the diffusion equation model for room-acoustic modeling. V
The Journal of the Acoustical Society of America, 2012
Room-acoustic energy decays often exhibit single-rate or multiple-rate characteristics in a wide ... more Room-acoustic energy decays often exhibit single-rate or multiple-rate characteristics in a wide variety of rooms/halls. Both the energy decay order and decay parameter estimation are of practical significance in architectural acoustics applications, representing two different levels of Bayesian probabilistic inference. This paper discusses a model-based sound energy decay analysis within a Bayesian framework utilizing the nested sampling algorithm. The nested sampling algorithm is specifically developed to evaluate the Bayesian evidence required for determining the energy decay order with decay parameter estimates as a secondary result. Taking the energy decay analysis in architectural acoustics as an example, this paper demonstrates that two different levels of inference, decay model-selection and decay parameter estimation, can be cohesively accomplished by the nested sampling algorithm. V
Since its inception in 2004, nested sampling has been used in acoustics applications. This work a... more Since its inception in 2004, nested sampling has been used in acoustics applications. This work applies nested sampling within a Bayesian framework to the detection and localization of sound sources using a spherical microphone array. Beyond an existing work, this source localization task relies on spherical harmonics to establish parametric models that distinguish the background sound environment from the presence of sound sources. Upon a positive detection, the parametric models are also involved to estimate an unknown number of potentially multiple sound sources. For the purpose of source detection, a no-source scenario needs to be considered in addition to the presence of at least one sound source. Specifically, the spherical microphone array senses the sound environment. The acoustic data are analyzed via spherical Fourier transforms using a Bayesian model comparison of two different models accounting for the absence and presence of sound sources for the source detection. Upon a positive detection, potentially multiple source models are involved to analyze direction of arrivals (DoAs) using Bayesian model selection and parameter estimation for the sound source enumeration and localization. These are two levels (enumeration and localization) of inferential estimations necessary to correctly localize potentially multiple sound sources. This paper discusses an efficient implementation of the nested sampling algorithm applied to the sound source detection and localization within the Bayesian framework.
Finite-difference methods are becoming increasingly popular in the acoustics community, and the i... more Finite-difference methods are becoming increasingly popular in the acoustics community, and the importance of higherorder methods has been acknowledged. However, the choice of an appropriate source for these methods has been largely overlooked in the acoustics literature. Published literature acknowledges the importance of selecting a continuous function, but it does not consider whether the function's derivatives are also continuous. The error resulting from discontinuous higher-order derivatives can contaminate a finite difference simulation with unnecessary, low-order, dispersive error, diminishing the order of accuracy of the overall scheme. This problem is discussed in the context of simple, wave equation solvers of various order with a variety of sources.
Journal of the Acoustical Society of America, Nov 1, 2019
Reverberation time measurements were conducted in the 21-lane indoor firing range at Wright Patte... more Reverberation time measurements were conducted in the 21-lane indoor firing range at Wright Patterson Air Force Base. Long reverberation times resulted in poor speech transmission indices (STI) which required acoustical treatments within the range. After treatment, reverberation times were significantly reduced and STI was dramatically enhanced. Standard Sabine and Eyring models failed to accurately predict the reverberation times. A computer simulation of the range was developed to predict room acoustic conditions and auralize speech performance for perceptual evaluation in the range.
In virtual auditory display via headphone, the unwanted spectral transformation (i.e., Headphone-... more In virtual auditory display via headphone, the unwanted spectral transformation (i.e., Headphone-to-ear-canal transfer functions, HpTFs) introduced by unflat headphone response and the acoustical coupling between the headphone transducer and the external ear should be eliminated in order to ensure authentic reproduction [1,2]. Since each person owns a unique dimension of external ear (especially pinna), HpTFs are individual-dependent. Acoustical measurement is a common way to obtain individual HpTFs. In practice, however, measurement errors from headphone and microphone placements are unavoidable. Moreover, measurement errors and individual characteristics are often mixed together, especially at high frequencies where both the measurement errors and the individual characteristics are obvious.
The Journal of the Acoustical Society of America, 2021
The acoustic diffusion equation model has been applied within a wide range of enclosure types to ... more The acoustic diffusion equation model has been applied within a wide range of enclosure types to simulate diffuse sound fields. Recently, focus has been drawn to its applicability in reverberation chambers to simulate sound fields among a heterogeneous distribution of absorbing materials, particularly those that are highly absorptive. Where quasi-diffuse or non-diffuse sound fields are generated in the presence of highly absorptive material, the acoustic diffusion equation model has convenient capabilities to simulate sound energy flow. Furthermore, it has continued to show promise in characterizing the absorption coefficients of sound absorbing material. Challenges for reproducibility in reverberation room measurements have been well-documented and where traditional chamber-based measurement have shown to be inconsistent, this work will evaluate the acoustic diffusion equation model’s suitability as an alternative and accurate method to characterize absorption coefficients.
The Journal of the Acoustical Society of America, 2019
This study investigates reliable models and methods to be applied in sound field analysis of mult... more This study investigates reliable models and methods to be applied in sound field analysis of multi-domain structures. The case structures are two monuments, namely, Süleymaniye Mosque and Hagia Sophia in İstanbul. These are both multi-volume spaces with many smaller sub-volumes coupled to each other by coupling apertures in form of arches. A key concern of the study is to examine energy flow decays and understand the mechanism of multi-slope sound energy decays. The methodology involves diffusion equation model (DEM) application in a finite-element scheme for sound energy flow analysis. Energy flow decays, energy flow dips, and spatial flow vectors are examined for single versus multi-domain DEM solutions. It is concluded that specification of different domains with individual diffusion coefficients is a critical setting such that, if not assigned correctly, may mislead the results. The energy flow vector analysis has enabled us to comprehend the architectural features in relation t...
The key concern of this study is to discuss the reliable acoustical metrics for analyzing particu... more The key concern of this study is to discuss the reliable acoustical metrics for analyzing particular sound fields within monumental multi-domed sacred spaces with an emphasis on multiple sound energy decay formation. The potential of such structures in featuring non-exponential sound energy decay characteristics necessitates new formulation of sound decay indicators in understanding of their sound fields. The early and late energy decay components within non-exponential sound energy decays can have a unique contribution to the interior acoustic quality. These acoustical features can also provide the functional and spiritual acoustical needs of monumental sacred spaces. Süleymaniye Mosque and Hagia Sophia, two major monuments of Istanbul World Heritage Site, are examined in this regard. Field measurements are the main method of data collection. Over collected room impulse responses, relevant acoustical predictors including decay rates and decay times are computed by applying Bayesian decay parameter estimation. Analysis results disclose double or triple decay formations in both structures. Authors argue that, the detection of multiple sound energy decays in analyzed structures sets out a new vision for room acoustics studies of sacred spaces and for multi-domed monuments. Thus, implementation of new metrics, namely multiple slope decay parameters to replace classical room acoustics indicators, is recommended and discussed in light of the outcomes of this study. Acoustical indicators • Multiple sound energy decay • Bayesian analysis • Sacred space acoustics • Süleymaniye Mosque • Hagia Sophia in İstanbul B Zühre Sü Gül
In this work, a diffusion equation model (DEM) is applied to a room acoustics case for in-depth s... more In this work, a diffusion equation model (DEM) is applied to a room acoustics case for in-depth sound field analysis. Background of the theory, the governing and boundary equations specifically applicable to this study are presented. A three-dimensional geometric model of a monumental worship space is composed. The DEM is solved over this model in a finite element framework to obtain sound energy densities. The sound field within the monument is numerically assessed; spatial sound energy distributions and flow vector analysis are conducted through the time-dependent DEM solutions.
The Journal of the Acoustical Society of America, 2013
Design for acoustic performance in an interior fluid domain requires accurate description of boun... more Design for acoustic performance in an interior fluid domain requires accurate description of boundary materials' specific acoustic impedance. The standard approach for the estimation of this material characteristic is the two-microphone, impedance-tube method. Modifications to the processing of the sampled acoustic field have been proposed to allow for more general test geometries. While analytical methods may be applied to a small class of ideal geometries, numerical methods provide greater geometric flexibility. In general, solutions to the wave equation forward problem are found from boundary element, finite element, or finite difference methods. The inverse problem of parameter estimation is solved by evaluating accuracy of prediction of the acoustic field for given distributions of the specific acoustic impedance parameter against observed data. In this presentation a Bayesian-network sampling approach is used to estimate specific acoustic impedance of a micro-perforated pa...
The Journal of the Acoustical Society of America, 2013
Nested sampling is increasingly being used to calculate the evidence for competing models in Baye... more Nested sampling is increasingly being used to calculate the evidence for competing models in Bayesian model comparison problems arising in acoustics applications. Use of nested sampling offers advantages in robustness over alternative methods of evidence calculation and enables evidence calculation for models with many parameters. The most challenging aspect of implementing nested sampling is sampling from the prior for the parameters constrained by a threshold likelihood value. For models with just a few parameters, sampling from the constrained prior can be accomplished with a simple Monte Carlo algorithm implementing a random walk, however, this simple method is inefficient and fails as the number of model parameters increases. John Skilling, the originator of nested sampling, has proposed the “Galilean” Monte Carlo method for efficiently sampling from the constrained prior when there are many parameters. Unlike the random walk method, the Galilean Monte Carlo method moves sample...
The Journal of the Acoustical Society of America, 2013
Markov Chain Monte Carlo (MCMC) algorithms for Bayesian model selection have been increasingly ap... more Markov Chain Monte Carlo (MCMC) algorithms for Bayesian model selection have been increasingly applied to acoustics applications. One of challenging tasks required in Bayesian model selection is the exploration of high-dimensional multi-variate spaces such that a key quantity, termed the Bayesian evidence, can be estimated in order to rank a set of competing models. This work presents a class of energy-based MCMC algorithms specifically designed to estimate the Bayesian evidence. As illustrative examples, the energy-based MCMC algorithms are applied to the problem of filter design as used in human head-related transfer functions and in acoustic impedance boundaries within the finite-difference time-domain framework for room-acoustics simulations.
Journal of the Acoustical Society of America, Jun 1, 2018
Coprime microphone arrays use sparse sensing to achieve greater degrees of freedom, while the cop... more Coprime microphone arrays use sparse sensing to achieve greater degrees of freedom, while the coprimality of the microphone subarrays help resolve grating lobe ambiguities. The result is a narrow beam at frequencies higher than the spatial Nyquist limit allows, with residual side lobes arising from aliasing. These side lobes can be mitigated when observing broadband sources, as shown by Bush and Xiang [J. Acoust. Soc. Am. 138, 447-456 (2015)]. Peak positions may indicate directions of arrival in this case; however, one must first ask how many sources are present. In answering this question, this work employs a model describing scenes with potentially multiple concurrent sound sources. Bayesian inference is used to first select which model the data prefer from competing models before estimating model parameters, including the particular source locations. The model is a linear combination of Laplace distribution functions (one per sound source). The likelihood function is explored by a Markov Chain Monte Carlo method called nested sampling in order to evaluate Bayesian evidence for each model. These values increase monotonically with model complexity; however, diminished returns are penalized via an implementation of Occam's razor.
Plane-wave decompositions, whereby a measured sound field is described as a superposition of plan... more Plane-wave decompositions, whereby a measured sound field is described as a superposition of plane waves, are central to many applications in acoustics and audio engineering. This letter applies a Bayesian probabilistic inference framework to the plane wave decomposition problem and examines the Deviance Information Criterion (DIC) for selecting the optimum number of waves in the decomposition. The framework learns the model directly from the data and, as such, adapts to the wavefield under study. The DIC is applied to data measured in two reverberant sound fields (highly-reverberant and lightly-damped) to determine the simplest models providing the preferred fit to the data.
Acoustic surface admittance/impedance at domain boundaries is essential for wave-based acoustic s... more Acoustic surface admittance/impedance at domain boundaries is essential for wave-based acoustic simulations. This work applies two levels of Bayesian inference to estimate the order and the parameter values of the multipole admittance model. The frequency-dependent acoustic admittance is experimentally measured. Incorporating the maximum entropy strategy, the unified Bayesian framework is applied to the multipole approximation. Analysis results demonstrate that multipole model-based Bayesian inference is well suited to estimating the arbitrary frequency-dependent boundary condition within a wave-based simulation framework.
If one of the goals of computational room acoustics is auralization, then one must also define ph... more If one of the goals of computational room acoustics is auralization, then one must also define physical accuracy criteria in terms of what is audible. Some types of errors, such as neglect of low-frequency modes and edge diffraction, may be so clearly audible that sophisticated psychoacoustic evaluation is sometimes unnecessary. On the other hand, computations of surface scattering may have errors on the order of 1-3 dB. one may ask when such errors are aurally significant. For example, small spectral changes audible for single scattering from a rough surface may not be audible in a room impulse response, depending on the density and decay rate of the reflections (and the corresponding degree of comb-filter effects), the similarity to frequency spectra of other reflections, the effects on the early or late parts of the impulse response, and the input signal that is used in a given auralization. This paper examines various room scattering computations and describes subjective methods for evaluating them in terms of aural adequacy. The tests for aural-adequacy employ time-frequency analysis, ABX listening tests, and multi-dimensional analysis of listening experiments to evaluate differences in numerical results.
The Journal of the Acoustical Society of America, 2013
Some recent concert hall designs have incorporated coupled reverberation chambers to the main hal... more Some recent concert hall designs have incorporated coupled reverberation chambers to the main hall that have stimulated a range of research activities in architectural acoustics. The coupling apertures between two or more coupled-volume systems are of central importance for sound propagation and sound energy decays throughout the coupled-volume systems. In addition, positions of sound sources and receivers relative to the aperture also have a profound influence on the sound energy distributions and decays. This work investigates the effect of aperture size on the behavior of coupled-volume systems using both acoustic scale-models and diffusion equation models. In these physical and numerical models, the sound source and receiver positions relative to the aperture are also investigated. Through systematic comparisons between results achieved from both physical scale models and numerical models, this work reveals valid ranges and limitations of the diffusion equation model for room-acoustic modeling. V
The Journal of the Acoustical Society of America, 2012
Room-acoustic energy decays often exhibit single-rate or multiple-rate characteristics in a wide ... more Room-acoustic energy decays often exhibit single-rate or multiple-rate characteristics in a wide variety of rooms/halls. Both the energy decay order and decay parameter estimation are of practical significance in architectural acoustics applications, representing two different levels of Bayesian probabilistic inference. This paper discusses a model-based sound energy decay analysis within a Bayesian framework utilizing the nested sampling algorithm. The nested sampling algorithm is specifically developed to evaluate the Bayesian evidence required for determining the energy decay order with decay parameter estimates as a secondary result. Taking the energy decay analysis in architectural acoustics as an example, this paper demonstrates that two different levels of inference, decay model-selection and decay parameter estimation, can be cohesively accomplished by the nested sampling algorithm. V
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