The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Etienne Corteel - One of the best experts on this subject based on the ideXlab platform.
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Practical 3 dimensional sound reproduction using Wave Field Synthesis, theory and perceptual validation
2012Co-Authors: Etienne Corteel, Lukas Rohr, Xavier Falourd, Khoa-van Nguyen, Hervé LissekAbstract:Sound field reproduction using Wave Field Synthesis has been so far limited to the positioning of virtual sources and listeners in the horizontal plane only. These simplifications were originally proposed to reduce the number of required Loudspeakers although the underlying formulation (Kirchhoff-Helmholtz) describes the reproduction of 3 dimensional sound fields in a 3 dimensional subspace. The authors propose here a revised formulation of Wave Field Synthesis in 3 dimensions that limits the number of required Loudspeakers, allowing for irregular and incomplete loudspeaker layouts. A source width control parameter is further proposed to reduce localization blur using a virtual source dependent loudspeaker selection criterion. The proposed approach is finally evaluated in an extended listening area. The experiment relies on an elevation localization comparison using individual Loudspeakers as targets and 3D WFS (with or without source width control) as pointer on a 24 channels loudspeaker array that covers the frontal quarter of the upper half of a rectangular room.
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practical 3 dimensional sound reproduction using wave field synthesis theory and perceptual validation
Proceedings of the 11th French Congress of Acoustics and 2012 Annual IOA Meeting, 2012Co-Authors: Etienne Corteel, Lukas Rohr, Xavier Falourd, Khoa-van Nguyen, Hervé LissekAbstract:Sound field reproduction using Wave Field Synthesis has been so far limited to the positioning of virtual sources and listeners in the horizontal plane only although the underlying formulation (Kirchhoff-Helmholtz) describes the reproduction of 3 dimensional sound fields in a 3 dimensional subspace. However, a strict use of this formulation would require a surface loudspeaker array with an impractical number of Loudspeakers. The authors propose here an optimized formulation of Wave Field Synthesis in 3 dimensions that account both for the limitation of localization accuracy of elevated sources and the target listening area size. In contrast to other 3 dimensional sound reproduction techniques such as Higher Order Ambisonics, the proposed approach allows for irregular and incomplete loudspeaker layouts for targeting specific areas for virtual positioning and accounting for practical limitations in loudspeaker positioning. The paper also proposes a subjective evaluation of the proposed approach in an extended listening area. The experiment relies on elevated physical sources (Loudspeakers) to be matched in localization with virtual sources reproduced with the proposed approach with a 24 channels loudspeaker array that covers the frontal quarter of the upper half of a rectangular room.
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On the use of irregularly spaced loudspeaker arrays for Wave Field Synthesis, potential impact on spatial aliasing frequency
2006Co-Authors: Etienne CorteelAbstract:Wave Field Synthesis (WFS) is a physical based sound reproduction technique. It relies on linear arrays of regularly spaced omnidirectional Loudspeakers. A fundamental limitation of WFS is that the synthesis remains correct only up to a corner frequency referred to as spatial aliasing frequency. This paper addresses irregular spacing of loudspeaker array for WFS. Adapted driving functions are defined. New formulations of the spatial aliasing frequency are proposed. It is shown that the use of logarithmically spaced loudspeaker arrays can significantly increase the spatial aliasing frequency for non focused virtual sources.
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Multi-Actuator Panel (MAP) Loudspeakers: how to compensate for their mutual reflections?
2004Co-Authors: Rik Von Zon, Etienne Corteel, Diemer De Vries, Olivier WarusfelAbstract:Wave Field Synthesis (WFS) allows reproducing the spatial and temporal properties of a target sound field over a large listening area. Thanks to their screen shape, Multi-Actuator Panels (MAP) represent a good alternative for WFS reproduction in multimedia installations. However, MAP speakers act as reflectors for acoustic waves which disturb the perception of the target soundfield. A general listening room compensation technique is proposed, based on multichannel inversion, that allows attenuating early reflections caused by a reflector using Loudspeakers integrated into this reflector (e.g. MAP Loudspeakers). After an analysis of the geometrical arrangement of the panels, the method processes separately the free field equalization of the loudspeaker array and the reflection compensation. Simulation and measurements show that the attenuation is effective over the entire listening area.
Hervé Lissek - One of the best experts on this subject based on the ideXlab platform.
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Practical 3 dimensional sound reproduction using Wave Field Synthesis, theory and perceptual validation
2012Co-Authors: Etienne Corteel, Lukas Rohr, Xavier Falourd, Khoa-van Nguyen, Hervé LissekAbstract:Sound field reproduction using Wave Field Synthesis has been so far limited to the positioning of virtual sources and listeners in the horizontal plane only. These simplifications were originally proposed to reduce the number of required Loudspeakers although the underlying formulation (Kirchhoff-Helmholtz) describes the reproduction of 3 dimensional sound fields in a 3 dimensional subspace. The authors propose here a revised formulation of Wave Field Synthesis in 3 dimensions that limits the number of required Loudspeakers, allowing for irregular and incomplete loudspeaker layouts. A source width control parameter is further proposed to reduce localization blur using a virtual source dependent loudspeaker selection criterion. The proposed approach is finally evaluated in an extended listening area. The experiment relies on an elevation localization comparison using individual Loudspeakers as targets and 3D WFS (with or without source width control) as pointer on a 24 channels loudspeaker array that covers the frontal quarter of the upper half of a rectangular room.
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practical 3 dimensional sound reproduction using wave field synthesis theory and perceptual validation
Proceedings of the 11th French Congress of Acoustics and 2012 Annual IOA Meeting, 2012Co-Authors: Etienne Corteel, Lukas Rohr, Xavier Falourd, Khoa-van Nguyen, Hervé LissekAbstract:Sound field reproduction using Wave Field Synthesis has been so far limited to the positioning of virtual sources and listeners in the horizontal plane only although the underlying formulation (Kirchhoff-Helmholtz) describes the reproduction of 3 dimensional sound fields in a 3 dimensional subspace. However, a strict use of this formulation would require a surface loudspeaker array with an impractical number of Loudspeakers. The authors propose here an optimized formulation of Wave Field Synthesis in 3 dimensions that account both for the limitation of localization accuracy of elevated sources and the target listening area size. In contrast to other 3 dimensional sound reproduction techniques such as Higher Order Ambisonics, the proposed approach allows for irregular and incomplete loudspeaker layouts for targeting specific areas for virtual positioning and accounting for practical limitations in loudspeaker positioning. The paper also proposes a subjective evaluation of the proposed approach in an extended listening area. The experiment relies on elevated physical sources (Loudspeakers) to be matched in localization with virtual sources reproduced with the proposed approach with a 24 channels loudspeaker array that covers the frontal quarter of the upper half of a rectangular room.
Filippo Maria Fazi - One of the best experts on this subject based on the ideXlab platform.
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Subjective Diffuseness in Layer-Based Loudspeaker Systems with Height
Journal of The Audio Engineering Society, 2015Co-Authors: Michael P. Cousins, Filippo Maria Fazi, Stefan Bleeck, Frank MelchiorAbstract:Loudspeaker systems with more channels and with elevated Loudspeakers are becoming more common. There is an opportunity for greater spatial impression with listeners surrounded in three dimensions. There is research showing the advantages of more Loudspeakers and of 3D layouts over 2D layouts although it is not clear whether the cause of these improvements is the greater number of loudspeaker, their position, or both. In this paper two listening tests are presented that investigate the subjective diffuseness of a range of loudspeaker layouts. The first experiment was used to optimize the distribution of loudness between horizontal layers of Loudspeakers to allow fair comparison between different layouts. The second experiment investigated the perceived diffuseness of a range of loudspeaker layouts chosen to critically assess parameters of layer-based loudspeaker systems as well as validate the results of the first experiment. The number of Loudspeakers at head-height, the number of Loudspeakers not at head-height, and the relative level between head-height and non-head-height layers were all found to be statistically significant in terms of perceived diffuseness. It was also confirmed that 3D loudspeaker layouts can have statistically greater perceived diffuseness than 2D layouts.
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3d soundfield reproduction using higher order Loudspeakers
International Conference on Acoustics Speech and Signal Processing, 2013Co-Authors: Prasanga N Samarasinghe, Mark A Poletti, S M A Salehin, Thushara D Abhayapala, Filippo Maria FaziAbstract:Three dimensional surround sound reproduction over large areas is a prevailing challenge due to the enormous numbers of Loudspeakers required. In this paper, we propose an array of higher order Loudspeakers which provide a mode matching solution to the problem based on 3D wavefield translation. It is shown that for a given bandwidth, the use of Lth order sources significantly brings down the minimum loudspeaker requirement by a factor of 1=(L + 1)2. Furthermore, the array is shown to be capable of exterior field cancellation, increasing its performance in echoing environments. Design examples are given for interior field, exterior field and interior and exterior combined field reproduction.
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sound field reproduction systems using fixed directivity Loudspeakers
Journal of the Acoustical Society of America, 2010Co-Authors: Mark A Poletti, Filippo Maria Fazi, P A NelsonAbstract:Sound reproduction systems using open arrays of Loudspeakers in rooms suffer from degradations due to room reflections. These reflections can be reduced using pre-compensation of the loudspeaker signals, but this requires calibration of the array in the room, and is processor-intensive. This paper examines 3D sound reproduction systems using spherical arrays of fixed-directivity Loudspeakers which reduce the sound field radiated outside the array. A generalized form of the simple source formulation and a mode-matching solution are derived for the required loudspeaker weights. The exterior field is derived and expressions for the exterior power and direct to reverberant ratio are derived. The theoretical results and simulations confirm that minimum interference occurs for Loudspeakers which have hyper-cardioid polar responses.
Mark A Poletti - One of the best experts on this subject based on the ideXlab platform.
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3d soundfield reproduction using higher order Loudspeakers
International Conference on Acoustics Speech and Signal Processing, 2013Co-Authors: Prasanga N Samarasinghe, Mark A Poletti, S M A Salehin, Thushara D Abhayapala, Filippo Maria FaziAbstract:Three dimensional surround sound reproduction over large areas is a prevailing challenge due to the enormous numbers of Loudspeakers required. In this paper, we propose an array of higher order Loudspeakers which provide a mode matching solution to the problem based on 3D wavefield translation. It is shown that for a given bandwidth, the use of Lth order sources significantly brings down the minimum loudspeaker requirement by a factor of 1=(L + 1)2. Furthermore, the array is shown to be capable of exterior field cancellation, increasing its performance in echoing environments. Design examples are given for interior field, exterior field and interior and exterior combined field reproduction.
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sound field reproduction systems using fixed directivity Loudspeakers
Journal of the Acoustical Society of America, 2010Co-Authors: Mark A Poletti, Filippo Maria Fazi, P A NelsonAbstract:Sound reproduction systems using open arrays of Loudspeakers in rooms suffer from degradations due to room reflections. These reflections can be reduced using pre-compensation of the loudspeaker signals, but this requires calibration of the array in the room, and is processor-intensive. This paper examines 3D sound reproduction systems using spherical arrays of fixed-directivity Loudspeakers which reduce the sound field radiated outside the array. A generalized form of the simple source formulation and a mode-matching solution are derived for the required loudspeaker weights. The exterior field is derived and expressions for the exterior power and direct to reverberant ratio are derived. The theoretical results and simulations confirm that minimum interference occurs for Loudspeakers which have hyper-cardioid polar responses.
Olivier Warusfel - One of the best experts on this subject based on the ideXlab platform.
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ESPRO 2.0 – Implementation of a surrounding 350-loudspeaker array for sound field reproduction
2012Co-Authors: Markus Noisternig, Thibaut Carpentier, Olivier WarusfelAbstract:The variable acoustics performance hall of IRCAM was designed and built for providing the largest variability possible with regard to form, volume, and surface material structure. Extending the remarkable flexibility of this room a surrounding 350-loudspeaker array has been recently installed. This system aims at the physically correct synthesis of acoustical wave fields applying wave field synthesis (WFS) and higher-order Ambisonics (HOA). This article reviews the theory of HOA with regard to the design of a feasible grid of Loudspeakers for this room, followed by a discussion of methods to overcome the practical limitations of using non-uniform loudspeaker arrays.
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Multi-Actuator Panel (MAP) Loudspeakers: how to compensate for their mutual reflections?
2004Co-Authors: Rik Von Zon, Etienne Corteel, Diemer De Vries, Olivier WarusfelAbstract:Wave Field Synthesis (WFS) allows reproducing the spatial and temporal properties of a target sound field over a large listening area. Thanks to their screen shape, Multi-Actuator Panels (MAP) represent a good alternative for WFS reproduction in multimedia installations. However, MAP speakers act as reflectors for acoustic waves which disturb the perception of the target soundfield. A general listening room compensation technique is proposed, based on multichannel inversion, that allows attenuating early reflections caused by a reflector using Loudspeakers integrated into this reflector (e.g. MAP Loudspeakers). After an analysis of the geometrical arrangement of the panels, the method processes separately the free field equalization of the loudspeaker array and the reflection compensation. Simulation and measurements show that the attenuation is effective over the entire listening area.
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On the Reproduction of Directivity Patterns Using Multi-Loudspeaker Sources
1995Co-Authors: Philippe Dérogis, René Causse, Olivier WarusfelAbstract:A sound source can generally be characterized by three physical properties: timber (spectral and temporal response), loudness and directivity. Although Loudspeakers give a faithful reproduction of timber and loudness, their own directivity can conflict with the directivity of the source they aim at reproducing. In the first section of this paper, we describe a general method for reproducing different sorts of directivity patterns using a multi-loudspeaker source. In the second section we apply this method to a particular source with twelve Loudspeakers grouped into few subsets for fitting the first zonal harmonics (spherical harmonics with axial symetry). Theoretical results are presented and compared with experimental measurements. These results show a good agreement between the prediction and the experiment below 500 Hz. But it appears, above this frequency, that our source don't correspond with the directivity patterns. In the third section we discuss the limitation of our work and show how our results could be improved by modifying the source geometry and increasing the number of Loudspeakers independently driven.
