Supervision: Romain Boulandet

Project type: Semester project (master) Master thesis

Finished

The distributed mode loudspeaker (DML) technology is a flat panel loudspeaker from which sound is generated a set of electromechanical actuators fixed on the panel, inducing distributed vibratory modes within the panel. It has many advantages over traditional cone loudspeakers in terms of weight, size, and durability. However, it is generally considered as a poor sound radiator at low frequencies, and the suual frequency response is uneven and complex, strongly dependent on the modal response of the vibrating structure. Compared to conventional loudspeakers which are increasingly directional with increasing frequency, DML are also highly diffusive and has a level of directivity which is largely independent of angle.

This project intends to investigate active structural acoustic control (ASAC) strategies to improve the low-frequency radiation efficiency of DML and provide a directive sound diffusion. The challenging problem is to identify the local control laws to assign on each independent control unit (electromechanical actuator + sensor) that will effectively alter the global acoustic radiation modes of the structure in order to achieve desired acoustic performance.

The proposed work will mainly consist in:

• studying different ASAC strategies on a finite element simulation software (COMSOL Multiphysics),
• defining an optimal configuration/strategy with respect to the sound diffusion specifications,
• achieving preliminary experimental assessments, on spare parts or a complete system.

Profile: Mechanical engineering

Context: Theory (20%), Design and modeling (60%), experiments (20%)