120th AES Convention - Paris, France - Dates: Saturday May 20 - Tuesday May 23, 2006 - Porte de Versailles

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AES Paris 2006

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Last Updated: 20060403, mei

P11 - Multichannel Sound, Part 2

Sunday, May 21, 14:00 — 15:20

Chair: Jason Corey, University of Michigan - Ann Arbor, MI, USA

P11-1 Implementation of Immersive Audio Applications Using Robust Adaptive Beamforming and Wave Field SynthesisJon Ander Beracoechea-Alava, Politechnical University of Madrid - Madrid, Spain; Soledad Torres-Guijarro, University of Vigo - Vigo, Spain; Lino García, European University of Madrid - Madrid, Spain; Javier Casajús, Luis Ortiz, Politechnical University of Madrid - Madrid, Spain
An immersive audio system oriented to future communication applications is presented. The aim is to build a system where the acoustic field in a chamber is recorded using a microphone array and then is reconstructed or rendered again, in a different chamber using loudspeaker array-based techniques. In order to reduce the enormous bandwidth necessary to deal with this setup, our proposal relies on recent robust adaptive beamforming techniques and joint audio-video source localization for effectively estimating the original sources of the emitting room. The estimated source and the source localization information drive a Wave Field Synthesis engine that renders the acoustic field again at the receiving chamber. The overall system performance is tested using a MUSHRA-based subjective test in a real situation.

Presentation is scheduled to begin at 14:00
Convention Paper 6710 (Purchase now)

P11-2 Spatial Aliasing Artifacts Produced by Linear and Circular Loudspeaker Arrays Used for Wave Field SynthesisSascha Spors, Deutsche Telekom Laboratories - Berlin, Germany; Rudolf Rabenstein, University of Erlangen-Nuremberg - Erlangen, Germany
Wave field synthesis allows the exact reproduction of sound fields if the requirements of its physical foundation are met. However, the practical realization imposes certain technical constraints. One of these is the application of loudspeaker arrays as an approximation to a spatially continuous source distribution. The effect of a finite spacing of the loudspeakers can be described as spatial sampling artifacts. This contribution derives a description of the spatial sampling process for planar linear and circular arrays, analyzes the sampling artifacts, and discusses the conditions for preventing spatial aliasing. It furthermore introduces the reproduced aliasing-to-signal ratio as a measure for the energy of aliasing contributions.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at 14:20
Convention Paper 6711 (Purchase now)

P11-3 Characterization of the Reverberant Sound Field Emitted by a Wave Field Synthesis Driven Loudspeaker ArrayTerence Caulkins, Olivier Warusfel, IRCAM - Paris, France
Realistic sound reproduction using wave field synthesis (WFS) in concert halls involves ensuring that both the direct and reverberated sound fields are accurate at all listening positions. Though methods for controlling the direct sound field have been described in the past, the control of the reverberated sound field associated to WFS sources remains a topic of interest. This paper describes the characteristics of the reverberated sound field associated to a WFS array as it synthesizes a virtual point source. Variations in the directivity and positioning of the virtual source are shown to have an effect on the associated room effect. A solution for controlling the reverberated sound field in a concert hall equipped with a WFS system is proposed based on this characterization.

[Associated Poster Presentation in Session P14, Sunday, May 21, at 16:00]

Presentation is scheduled to begin at14:40
Convention Paper 6712 (Purchase now)

P11-4 Conjugate Gradient Techniques for Multichannel Acoustic Echo Cancellation in Frequency DomainLino García Morales, Universidad Europea de Madrid - Madrid, Spain; Jon Ander Beracoechea, Universidad Politécnica de Madrid - Madrid, Spain; Soledad Torres-Guijarro, Universidad de Vigo - Vigo, Spain; Francisco Javier Casajús-Quirós, Universidad Politécnica de Madrid - Madrid, Spain
Multichannel acoustic cancellation problem requires working with extremely large impulse responses. Multirate adaptive schemes such as the partitioned block frequency-domain adaptive filter (PBFDAF) are good alternatives and are widely used in commercial echo cancellation systems nowadays. However, being a Least Mean Square (LMS) derived algorithm, the convergence speed may not be fast enough under some circumstances. In this paper we propose a new scheme that combines frequency-domain adaptive filtering with conjugate gradient techniques in order to speed up the convergence time. The new algorithm (PBFDAF-CG) is developed and its behavior is compared against previous PBFDAF schemes.

Presentation is scheduled to begin at 15:00
Convention Paper 6713 (Purchase now)

  (C) 2006, Audio Engineering Society, Inc.