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The University of Southampton
Engineering

Electroacoustic Metamaterials: towards programmable acoustic interfaces for sound field control Seminar

Time:
16:00 - 17:00
Date:
4 October 2022
Venue:
25/2015

For more information regarding this seminar, please email Vanui Mardanyan at isvr@southampton.ac.uk .

Event details

ISVR Research seminar

Acoustic metamaterials (/metasurfaces) have raised a growing interest in the scientific community during the last decade, exhibiting a wide range of amazing acoustic properties (negative refraction, anomalous reflection/transmission, etc.). One of the specificities of such concept is that the size of their elementary constitutive elements is much smaller than the wavelength of interest. Such metamaterials can then be employed for designing practically small soundproofing materials for the (audible) low-frequency regime, where conventional solutions (obeying the “quarter-wavelength” rule) are unavoidably cumbersome. However, most if not all of the metamaterial structures reported so far fail to show applicable properties, mainly due to passive structures that are inherently resonant and lossy, therefore effective only over very limited frequency bandwidths, if not ineffective at all.

The development of active acoustic control techniques may allow overcoming such limitations. In this talk, I will present the concept of Electroacoustic Resonator that I developed in the last decade, allowing turning a conventional loudspeaker into a broadband sound absorber with adjustable acoustic properties, that can be easily tuned on-the-fly. Several applications of the concepts have been successfully assessed so far, such as low-frequency room modes damping (this work has led to the only commercial product available on the market, AVAA C20 by PSI Audio), or Tunable Acoustic Liners for aircraft engines noise reduction. New routes are now envisaged towards the application of such active resonators to metamaterials and metasurfaces, in a view to achieving controllable and broadband sound wave redirection (reflection/transmission), with potential applications to room acoustics and noise control engineering.

 

Speaker information

Dr Hervé Lissek, EPFL. After a PhD in Acoustics in 2002, Dr. Lissek joined EPFL and the Laboratoire d’Electromagnétisme et d’Acoustique (LEMA) to supervise the active noise control activities of the Acoustic Research Group, headed by Prof. Mario Rossi. In 2006, Dr. Lissek took the leadership of the Acoustic Group, and launched several expertise activities together with new research topics, especially in the frame of Aircraft Noise Research in EU projects (FP7-TEENI, FP7-OPENAIR, FP7-XNOISE EV, FP7-ENOVAL, H2020-SmartAnswer, H2020-ARTEM, H2020-SALUTE). Since 2015, Hervé Lissek and the Acoustic Group are affiliated to the Laboratoire de Traitement des Signaux 2 (LTS2) with Pierre Vandergheynst. The research activities range from acoustic signal processing (spatial sound rendering in hearing-aids, compressive sensing of sound fields) to acoustic metamaterials (acoustic prism, non-Hermitian acoustic media), through active sound absorption (low-frequency room modes damping, aircraft engine noise reduction) and novel electroacoustic transducers concepts (corona discharge loudspeaker).

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