Adaptive Control of Low-Frequency Acoustic Modes in Small Rooms

摘要

The work presents the implementation in software of an adaptive method for reducing the non-uniformity ofthe frequency-response-curve, by covering certain walls of small rectangular rooms, with a particular type of a passiveacoustical treatment, consisting of porous absorbents covered with perforated sheets, in which each perforation behavesindependently as Helmholtz resonators. The method employs new developments of another publication for finding themodal 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 ofacoustical treatment and would allow the implementation of new types of treatments as desired. Some testing results arepresented, demonstrating the ability of the software for finding best parameters of the acoustical treatment, giving as inputdata the room dimensions and source/receiver locations only.