Publications associées à Coaxial loudspeaker

The Advection Boundary Law in presence of mean-flow and spinning modes

In the attempt to reduce fuel consumption, a new generation of Ultra-High-By-Pass-Ratio (UHBR) turbofans have been introduced in the aeronautic industry which are structurally noisier especially at lower frequencies, because of their larger diameter, lower ...

SPIE2024

Geometric optimization of dielectric elastomer electrodes for dynamic applications

Herbert Shea, Bekir Aksoy, Emil Yan Garnell

Dielectric elastomers are soft actuators, made of an elastomer membrane sandwiched by compliant electrodes. Because of their high energy density and quick response, they are well suited for dynamic applications such as loudspeakers. Thanks to progress in t ...

ELSEVIER SCI LTD2021

Toward Wideband Steerable Acoustic Metasurfaces with Arrays of Active Electroacoustic Resonators

Romain Christophe Rémy Fleury, Hervé Lissek, Etienne Thierry Jean-Luc Rivet, Thomas Laurence

We introduce an active concept for achieving acoustic metasurfaces with steerable reflection properties, effective over a wide frequency band. The proposed active acoustic metasurface consists in a surface array of subwavelength loudspeakers diaphragms, ea ...

2018

Sensorless Electroacoustic Absorbers Through Synthesized Impedance Control for Damping Low-Frequency Modes in Cavities

Hervé Lissek, Romain Boulandet, Etienne Thierry Jean-Luc Rivet

This paper presents a concept of sensorless electroacoustic absorber for damping the low-frequency modes in a cavity such as a duct or a room. Taking advantage of the reciprocity of the voice coil transducer, it is shown that a synthetic electrical admitta ...

S Hirzel Verlag2016

A sound diffusion system for directional sound enhancement

Hervé Lissek, Alain Dufaux, Xavier Falourd, Alexandre Delidais, Patrick Marmaroli, Baptiste Crettaz, Cédric Monchâtre

A loudspeaker array is described including several circular sound emitters that are bunked. One circular sound emitter can be either a circular array of loudspeakers (kind 1) or a toroidal loudspeaker (kind 2). The loudspeaker array can be composed of circ ...

André Roland S.A.2015

Automatic social role recognition and its application in structuring multiparty interactions

Ashtosh Sapru

Automatic processing of multiparty interactions is a research domain with important applications in content browsing, summarization and information retrieval. In recent years, several works have been devoted to find regular patterns which speakers exhibit ...

EPFL2015

Toward broadband electroacoustic resonators through optimized feedback control strategies

Hervé Lissek, Romain Boulandet

This paper presents a methodology for the design of broadband electroacoustic resonators for low-frequency room equalization. An electroacoustic resonator denotes a loudspeaker used as a membrane resonator, the acoustic impedance of which can be modified t ...

Elsevier2014

Electroacoustic metamaterials: achieving negative acoustic properties with shunt loudspeakers

Hervé Lissek

Acoustic metamaterials constitute a new class of structures that exhibit acoustic properties not readily available in nature. These properties can be a negative mass density, expressing the opposition of the acceleration of a particle to the application of ...

2013

Advanced control for modifying the acoustic impedance at the diaphragm of a loudspeaker

Hervé Lissek, Romain Boulandet, Etienne Thierry Jean-Luc Rivet

The control of low-frequency sound fields can be addressed efficiently through acoustic impedance matching. Basically, the diaphragm of electroacoustic transducers are used as refracting surface that controls the reaction of the boundaries in any surroundi ...

2012

Multi-channel low-frequency room equalization using perceptually motivated constrained optimization

Martin Vetterli, Mihailo Kolundzija, Christof Faller

We consider the problem of multiple-loudspeaker low-frequency room equalization for a wide listening area, where the equalized loudspeaker is helped using the remaining ones. Using a spatial discretization of the listening area, we formulate the problem as ...

Ieee2012

Design of Shunt Electric Networks in View of Sound Absorption with Loudspeakers

Hervé Lissek, Romain Boulandet

Variable acoustic properties can be obtained at the diaphragm of a loudspeaker, with the help of very basic control strategies, among which is the simple electrical shunting of the transducer. These shunt techniques have been demonstrated to present singul ...

2011

Method and Device for Removing Echo in an Audio Signal

Christof Faller

Acoustic echo control and noise suppression is an important part of any "handsfree" telecommunication system, such as telephony or audio or video conferencing systems. Bandwidth and computational complexity constraints have prevented that stereo or multi-c ...

2010

Baffled Circular Loudspeaker Array With Broadband High Directivity

Martin Vetterli, Mihailo Kolundzija, Christof Faller

Super-directional loudspeaker arrays can be used to achieve high directivity in a limited low-frequency range. As opposed to microphone arrays, the distance between the loudspeakers has to be relatively large, resulting in aliasing starting at relatively l ...

2010

Method And Device For Removing Echo In A Multi-Channel Audio Signal

Christof Faller

Acoustic echo control and noise suppression is an important part of any "handsfree" telecommunication system, such as telephony or audio or video conferencing systems. Bandwidth and computational complexity constraints have prevented that stereo or multi-c ...

2008

Method to generate multi-channel audio signals from stereo signals

Christof Faller

A perceptually motivated spatial decomposition for two-channel stereo audio signals, capturing the information about the virtual sound stage, is proposed. The spatial decomposition allows to re-synthesize audio signals for playback over other sound systems ...

2007

Stereo Acoustic Echo Control Using A Simplified Echo Path Model

Christof Faller, Christophe Tournery

In handsfree tele- or video-communication, acoustic echoes arise due to the coupling between the loudspeakers and microphones. It is much more challenging to remove the undesired acoustic echoes for stereo or multi-channel tele-communication systems than f ...

2006

Robust Acoustic Echo Control Using a Simple Echo Path Model

Christof Faller, Christophe Tournery

In handsfree tele or video conferencing acoustic echoes arise due to the coupling between the loudspeaker and microphone. Usually an acoustic echo canceler (AEC) is used for eliminating the undesired echoes. The weaknesses of AEC are that it is relatively ...

2006

Estimating the Delay and Coloration Effect of the Acoustic Echo Path for Low Complexity Echo Suppression

Christof Faller, Christophe Tournery

Acoustic echoes arise whenever there is acoustic coupling between a loudspeaker and a microphone. A traditional solution for eliminating the undesired echo signal is an acoustic echo canceler (AEC), which identifies the echo path between a loudspeaker and ...

2005

Compensation des non-linéarités des systèmes haut-parleurs à pavillon

Delphine Bard

The assumptions of linearity and autonomy assumed in circuit theory are known to be respected only partially by electroacoustic transducers. In particular, the dynamics range of the latter is limited by the audible nonlinear effects that they are causing. ...

EPFL2005