Supervision: Stanislav Sergeev

Project type: Semester project (master)

Finished

Plasma technology can be used for sound diffusion without resorting to a vibrating membrane and a cumbersome driver (as in conventional loudspeakers), which presents several practical advantages (thinness of the loudspeaker, mechanical simplicity, etc.). A recent development in the laboratory led to the construction of a square plasma loudspeaker of 25 cm x 25 cm, which acoustic performance can be considered comparable to equivalent sized moving coil loudspeakers.

Besides sound diffusion, using such plasma transducer for active sound absorption could also be advantageous, especially due to the absence of membrane, that is a limiting factor of loudspeaker-based concepts (such as the electroacoustic absorber developed in the lab). Indeed, it has been shown that such plasma-based sound absorber outperform conventional loudspeaker-based active absorber in terms of frequency range of absorption, mainly due to the absence of membrane.

In this project, we aim at building an experimental prototype of corona-discharge sound absorber that could be used as a demonstrator for room mode damping at low-frequencies, based on the most recent design of plasma loudspeaker. The work will be split into the following tasks:

• COMSOL simulations to find optimal configuration for the plasma sound absorber

• construction of a prototype, including electrical powering and control architecture

• development of the experimental facility to characterize the acoustic performance of such prototype

• in situ assessment as room mode damping device

Prerequisite: Audio engineering lecture

Learning outcomes: Plasma-based loudspeaker, Active control, Acoustic measurements

Context: COMSOL simulations (30%), Prototype construction (30%), Acoustic assessment (40 %)