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Concept

Bass reflex

Publications associées (12)

Robust direct acoustic impedance control using two microphones for mixed feedforward-feedback controller

Hervé Lissek, Maxime Volery, Xinxin Guo

This paper presents an acoustic impedance control architecture for an electroacoustic absorber combining both feedforward and feedback microphone-based strategies on a current-driven loudspeaker. Feedforward systems enable good performance for direct imped ...

EDP SCIENCES S A2023

PID-like active impedance control for electroacoustic resonators to design tunable single-degree-of-freedom sound absorbers

Hervé Lissek, Maxime Volery, Xinxin Guo

Sound absorption at low frequencies still remains a challenge in both scientific research and engineering practice. Natural porous materials are ineffective in this frequency range, as well as acoustic resonators which present too narrow bandwidth of absor ...

2022

Numerical investigation of optimal divertor gas baffle closure on TCV

Stefano Coda, Benoît Labit, Holger Reimerdes, Christian Gabriel Theiler, Mirko Wensing, Davide Galassi

A first set of divertor gas baffles has recently been installed in the TCV tokamak. In order to explore the physics determining the benefits and limitations of divertor baffling and to guide the design of a possible second generation of baffles, the effect ...

2020

Duct modes damping through an adjustable electroacoustic liner under grazing incidence

Hervé Lissek, Romain Boulandet

This paper deals with active sound attenuation in lined ducts with flow and its application to duct modes damping in aircraft engine nacelles. It presents an active lining concept based on an arrangement of electroacoustic absorbers flush mounted in the du ...

2018

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

On the Optimisation of Multi-Degree-of-Freedom Acoustic Impedances of Low-Frequency Electroacoustic Absorbers for Room Modal Equalisation

Hervé Lissek, Sami Driss Karkar, Etienne Thierry Jean-Luc Rivet

Low-frequency electroacoustic absorbers have recently been developed as a solution for the modal equalisation. Firstly investigated in waveguides, the technique consists in matching the acoustic impedance at a closed-box loudspeaker diaphragm to the charac ...

2017

Experimental assessment of low-frequency electroacoustic absorbers for room modal equalization in actual listening rooms

Hervé Lissek, Sami Driss Karkar, Etienne Thierry Jean-Luc Rivet, Véronique Adam

In listening rooms, low-frequency modal resonances lead to uneven distributions in space and frequency of the acoustic energy, as well as an alteration of the temporal behavior of the original music content. While usual absorption techniques have severe li ...

AES2016

Room Modal Equalisation with Electroacoustic Absorbers

Etienne Thierry Jean-Luc Rivet

The sound quality in a room is of fundamental importance for both recording and reproducing processes. Because of the room modes, the distributions in space and frequency of the sound field are largely altered. Excessive rise and decay times caused by the ...

EPFL2016

Analysis and Design of Mobile Device Antenna-Speaker Integration for Optimum Over-the-Air Performance

Juan Ramon Mosig

In this paper, the mutual coupling between a mobile device antenna and a closely integrated miniature moving-coil speaker is investigated. The analysis focuses on the speaker radio-frequency harmonic resonance characteristics and the antenna radiation effi ...

Institute of Electrical and Electronics Engineers2015

Optimization of electroacoustic resonators for semi-active room equalization in the low-frequency range

Hervé Lissek, Etienne Thierry Jean-Luc Rivet

At low frequencies, standing waves within the room cause large frequency-response variations in the listening environment, such as audio rooms or recording studios. This unwanted phenomenon has a significant impact on the sound quality of an audio system. ...

2013

Assessment of active electroacoustic absorbers as low-frequency modal dampers in rooms

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

In small to medium size rooms, natural room modes may severely strengthen the annoyance of low frequency noises, such as traffic or equipment noise. Moreover, there is an actual technological gap in the state-of-the-art concerning low-frequency treatments, ...

2012

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