Adaptive Control of Low-Frequency Acoustic Modes in Small Rooms

ABSTRACT

The work presents the implementation in software of an adaptive method for reducing the non-uniformity of the frequency-response-curve, by covering certain walls of small rectangular rooms, with a particular type of a passive acoustical treatment, consisting of porous absorbents covered with perforated sheets, in which each perforation behaves independently as Helmholtz resonators. The method employs new developments of another publication for finding the modal parameters, namely natural frequencies and associated damping constants, of rectangular rooms with arbitrary (uniform) wall-impedances. The adaptive software is capable of continuously improving the implemented type of acoustical treatment and would allow the implementation of new types of treatments as desired. Some testing results are presented, demonstrating the ability of the software for finding best parameters of the acoustical treatment, giving as input data the room dimensions and source/receiver locations only.

Keywords:

Acoustics of small rooms, acoustic treatment of small rooms, ntrol of low-frequency acoustic modes in small rooms.