Patent ID: 7210897

Claim:
An actively-controlled sound absorption panel system using a movement-controlled reflective plate comprising: a sound absorption panel section in which a sound absorption space is formed by a surface plate made of a perforated plate, side plates with porous sound absorption material stuck thereon, and a back sheet plate with porous sound absorption material stuck thereon, and a movement-controlled reflective plate is provided in said sound absorption space such that said movement-controlled reflective plate is slightly smaller than said perforated plate, having a porous sound absorption material stuck onto the inside wall face thereof, and is capable of controlling movement and rotation with respect to said perforated plate; and an active sound absorption control system section having a sensing sensor and an error sensor arranged facing the noise field on either side of said sound absorption panel section, a signal processor that performs processing such that the difference of the overall sound pressure levels measured by said two sensors is a maximum and that outputs a control signal relating to the mode and position of said reflective plate, and a movement-controlled reflective plate drive control motor driven by the control signal from this signal processor; wherein provision is made such that noise in a wide frequency range can be actively absorbed in an optimal fashion, by controlling the mode and position of said movement-controlled reflective plate in response to change of the noise source character.