Concept

Diaphragm (acoustics)

Related publications (26)

Robust tunable acoustic impedance control on electroacoustic resonators for aircraft noise reduction

Air traffic noise emissions are responsible for a significant part of the overall environmental noise, especially in the vicinity of airports. Exposure to environmental noise is known to negatively impact health and to be associated with cardiovascular dis ...

EPFL2023

Numerical simulations of retrofitting interventions on timber floors in unreinforced masonry

Katrin Beyer, Igor Tomic, Ivana Bozulic

Unreinforced masonry buildings with flexible timber floors are amongst the most vulnerable building typologies for seismic loading. Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the impact of the connect ...

2022

Plasma-based Electroacoustic Actuator for Broadband Sound Absorption

Stanislav Sergeev

Environmental noise, mostly related to human activities, has an immense impact on public health. The development of noise reduction technologies is paramount in addressing this problem. Because of practical and economic reasons, a compact, broadband, light ...

EPFL2022

Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms

Katrin Beyer, Igor Tomic, Francesco Vanin, Ivana Bozulic

Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexi ...

2021

Sound Field Reconstruction in a room through Sparse Recovery and its application in Room Modal Equalization

Vu Thach Pham

The acoustics of a room often refer to the quality of the room in terms of sound recording as well as sound reproduction. At low frequencies, where the wavelengths are of the same order of magnitude with the dimensions of the room, due to the standing wave ...

EPFL2021

MOCCA: Modeling and Optimizing Cone-joints for Complex Assemblies

Mark Pauly, Ziqi Wang, Peng Song

We present a computational framework for modeling and optimizing complex assemblies using cone joints. Cone joints are integral joints that generalize traditional single-direction joints such as mortise and tenon joints to support a general cone of directi ...

2021

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

Characterization of Cold-Formed Steel Framed/Wood Sheathed Floor and Roof Diaphragm Structures

Dimitrios Lignos

The seismic in-plane response of cold-formed steel (CFS) framed diaphragm structures has not been the subject of extensive study. The information available specific to diaphragm design in the North American CFS design standard is based on limited experimen ...

International Association of Earthquake Engineering2017

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

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

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

Design considerations to enhance the performances of thin circular piezoelectric energy harvester diaphragms in harsh liquid environments

Nico de Rooij

Thin circular piezoelectric energy harvester diaphragms undergoing large deflection in a harsh liquid environment are investigated in this paper. A material set combining AlN as transducer, SiC as electronics, Mo as wiring and Si as holder is considered. A ...

Iop Publishing Ltd2013

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

On the damping of room resonances with electroacoustic absorbers in the low frequency range

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

In closed spaces, standing waves occur at low frequencies, thus creating annoying acoustic resonances. Such unwanted phenomena are likely to affect the annoyance of noise sources in the low frequency range. Up to date, low-frwquency treatments are mainly b ...

2012

Study on room modal equalization at low frequencies with electroacoustic absorbers

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

Nowadays, requirements for acoustic treatments in rooms are ever more demanding in terms of performance and compactness. A recurring issue in closed spaces is the occurrence of standing waves and acoustic interferences at low frequencies. These unwanted ph ...

2012

Tunable Electroacoustic Resonators through Active Impedance Control of Loudspeakers

Romain Boulandet

The current trend for multipurpose rooms requires enhanced acoustic treatments capable to meet ever more demanding specifications in terms of performance, compactness and versatility. The reason is the variety of activities to be hosted and the correspondi ...

EPFL2012

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

Design and assessment of an electrodynamic loudspeaker used in a variable acoustic lining concept

Hervé Lissek, Anne-Sophie Moreau

The acoustic impedance at the diaphragm of an electroacoustic transducer can be modified using a range of active control strategies, amongst which is “direct impedance control”. This technique employs a combination of feedbacks, one on the acoustic pressur ...

2011

Reproducing Sound Fields Using MIMO Acoustic Channel Inversion

Martin Vetterli, Christof Faller, Mihailo Kolundzija

Sound fields are essentially band-limited phenomena, both temporally and spatially. This implies that a spatially sampled sound field respecting the Nyquist criterion is effectively equivalent to its continuous original. We describe Sound Field Reconstruct ...

2011