Supervision: Romain Boulandet,Thomas Laurence

Project type: Semester project (master) Master thesis

Finished

SounDDot is a technology recently developed in the laboratory, providing highly directive sound-diffusion. It is based on an array of small sound sources, arranged in different layers, and fed with a signal processed so as to optimize the contrast of the sound level of music rendered in a predefined small area compared to the surroundings. The device is embedded in a rather small cabinet to be suspended on the ceiling of a wide space (such as museum, halls, etc.), delivering the maximum amount of sound energy in a small surface below. The performances achieved in laboratory conditions are satisfactory, as well as public experiments during the last editions of the Montreux Jazz Festival. However, the noise activity around the listening zone might be too important and decrease the listening experience. The next development step of this prototype will consist in developing active noise control devices to improve the confinement of the listening zone within the surrounding of the device. To that end, we would like to investigate the possibility to apply active loudspeakers inside or around the body of the SounDDot. The control strategies are manifold:

• it might either consist in cancelling out the sound waves travelling from outside to the target listening zone, with secondary loudspeakers,
• or it might be done by changing the absorption properties of the body, thus the local acoustic environment below the SounDDot, through the implementation of active impedance control

The proposed work will mainly consist in studying different active control strategies on a physics simulation software (COMSOL Multiphysics) and define an optimal configuration/strategy with respect to noise isolation specifications. If time is remaining, preliminary experimental assessment, on spare parts or a complete system, will conclude the project.

Profile: Electrical engineering, Micro-engineering, Physics, Mechanics

Prerequisites: Audio Engineering (MA1)

Context: Theory (20%), design (60%), experiments (20%)