Simulation of realistic background noise using multiple loudspeakers

Modern communication devices, e.g. mobile phones, headsets or hearing aids, utilize noise suppression algorithms in order to minimize the effect of background noise in communication. Recent devices make use of multiple microphones for the suppression of background noise and this requires reproducing realistic sound fields using multiple loudspeakers to ensure the spatial information in the reproduced sound field preserves. The standardized reproduction method is based on the equalization of acoustical paths between loudspeakers to the microphone positions for recording. This enable to reproduce the sound field precisely around the microphone positions, but poor performance in other places in the reproduced sound field. Compared to that, higher-order ambisonics (HOA) is an approach to reconstruct the sound field close to the original one using spherical harmonics decomposition. HOA may be able to reconstruct the sound field including the directivity of individual sources, but typically requires a lot of loudspeakers to be used.

The goal of the project is to implement both the equalization-based method and HOA, and to find an optimal and reasonable number of loudspeakers and their layout for realistic sound reproduction. The outcome will be an optimal loudspeaker setup with reasonable amount of loudspeakers, which can be used for testing modern communication devices.

Read the report here

Project participants:
Brüel og Kjær Sound & Vibration Measurement A/S
GN Netcom A/S, Danmark 

For more information, contact Project Leader:
Professor Torsten Dau
Technical University of Denmark, CAHR
tdau@elektro.dtu.dk