Theoretical Analysis of Open Spherical Microphone Arrays for Acoustic Intensity Measurements

Hacıhabiboğlu, Hüseyin

doi:10.1109/taslp.2013.2294581

Cited by 12 publications

(9 citation statements)

References 30 publications

(43 reference statements)

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“…where denotes the real operator, * denotes the complex conjugate operator, p is the sound pressure, ρ 0 is the mean density of the medium, c is the speed of sound, and u is the particle velocity. Note that the particle velocity may be used in this manner, with the assumption that the sound sources are in the far-field [44]. The parameters may then be estimated as…”

Section: Legacy Spatial Impulse Response Renderingmentioning

confidence: 99%

Higher-Order Spatial Impulse Response Rendering: Investigating the Perceived Effects of Spherical Order, Dedicated Diffuse Rendering, and Frequency Resolution

McCormack¹,

Pulkki

Politis³

et al. 2020

J. Audio Eng. Soc.

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This article details an investigation into the perceptual effects of different rendering strategies when synthesizing loudspeaker array room impulse responses (RIRs) using microphone array RIRs in a parametric fashion. The aim of this rendering task is to faithfully reproduce the spatial characteristics of a captured space, encoded within the input microphone array RIR (or the spherical harmonic RIR derived from it), over a loudspeaker array. For this study, a higherorder formulation of the Spatial Impulse Response Rendering (SIRR) method is introduced and subsequently employed to investigate the perceptual effects of the following rendering configurations: the spherical harmonic input order, frequency resolution, and utilizing dedicated diffuse stream rendering. Formal listening tests were conducted using a 64-channel loudspeaker array in an anechoic chamber, where simulated reference scenarios were compared against the outputs of different methods and rendering configurations. The test results indicate that dedicated diffuse stream rendering and higher analysis orders both yield noticeable perceptual improvements, particularly when employing problematic transient stimuli as input. Additionally, it was found that the frequency resolution employed during rendering has only a minor influence over the perceived accuracy of the reproduction in comparison to the other two tested attributes.

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Section: Legacy Spatial Impulse Response Renderingmentioning

confidence: 99%

Higher-Order Spatial Impulse Response Rendering: Investigating the Perceived Effects of Spherical Order, Dedicated Diffuse Rendering, and Frequency Resolution

McCormack¹,

Pulkki

Politis³

et al. 2020

J. Audio Eng. Soc.

View full text Add to dashboard Cite

show abstract

“…Alternatively, such an evaluation can be carried out using a sound field reconstruction method based on plane wave decomposition [84] or point source expansion [28]. Furthermore, a measurement-based derivation of energy and velocity vectors [85,86] potentially provides a more reliable prediction of the overall in-situ performance across decoders.…”

Section: Limitationsmentioning

confidence: 99%

SCaLAr – A surrounding spherical cap loudspeaker array for flexible generation and evaluation of virtual acoustic environments

2020

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Introduction: Surrounding spherical loudspeaker arrays facilitate the application of various spatial audio reproduction methods and can be used for a broad range of acoustic measurements and perceptual evaluations. Methods: Installed in an anechoic chamber, the design and implementation of such an array of 68 coaxial loudspeakers, sampling a spherical cap with a radius of 1.35 m on an equal-area grid, is presented. A network-based audio backbone enables low-latency signal transmission with low-noise amplifiers providing a high signal-to-noise ratio. To address batch-to-batch variations, the loudspeaker transfer functions were equalised by individually designed 512-taps finite impulse response filters. Time delays and corresponding level adjustments further helped to minimise radial mounting imperfections. Results: The equalised loudspeaker transfer functions measured under ideal conditions and when mounted, their directivity patterns, and in-situ background noise levels satisfy key criteria towards applicability. Advantages and shortcomings of the selected decoders for panning-based techniques, as well as the influence of loudspeaker positioning errors, are analysed in terms of simulated performance metrics. An evaluation of the achievable channel separation allows deriving recommendations of feasible subset layouts for loudspeaker-based binaural reproduction. Conclusion: The combination of electroacoustic properties, simulated sound field synthesis performance and measured channel separation classifies the system as suitable for its target applications.

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“…where denotes the real operator; * denotes the complex conjugate operator; p is the sound pressure, estimated as the omnidirectional signal p s 00 ; and u is the particle velocity, which can be estimated using the pressure gradient signals [45], assuming that the sound sources are received as planewaves, as 1…”

Section: Active-intensity Vector Estimationmentioning

confidence: 99%

Applications of Spatially Localized Active-Intensity Vectors for Sound-Field visualization

McCormack¹,

Delikaris-Manias²,

Politis³

et al. 2019

J. Audio Eng. Soc.

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The purpose of this article is to detail and evaluate three alternative approaches to soundfield visualization, which all employ the use of spatially localized active-intensity (SLAI) vectors. These SLAI vectors are of particular interest, as they allow direction-of-arrival (DoA) estimates to be extracted in multiple spatially localized sectors, such that a sound source present in one sector has reduced influence on the DoA estimate made in another sector. These DoA estimates may be used to visualize the sound-field by either: (I) directly depicting the estimates as icons, with their relative size dictated by the corresponding energy of each sector; (II) generating traditional activity maps via histogram analysis of the DoA estimates; or (III) by using the DoA estimates to reassign energy and subsequently sharpen traditional beamformer-based activity maps. Since the SLAI-based DoA estimates are continuous, these approaches are inherently computationally efficient, as they forego the need for dense scanning grids to attain high-resolution imaging. Simulation results also show that these SLAI-based alternatives outperform traditional active-intensity and beamformer-based approaches, for the majority of cases.

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Theoretical Analysis of Open Spherical Microphone Arrays for Acoustic Intensity Measurements

Cited by 12 publications

References 30 publications

Higher-Order Spatial Impulse Response Rendering: Investigating the Perceived Effects of Spherical Order, Dedicated Diffuse Rendering, and Frequency Resolution

Higher-Order Spatial Impulse Response Rendering: Investigating the Perceived Effects of Spherical Order, Dedicated Diffuse Rendering, and Frequency Resolution

SCaLAr – A surrounding spherical cap loudspeaker array for flexible generation and evaluation of virtual acoustic environments

Applications of Spatially Localized Active-Intensity Vectors for Sound-Field visualization

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