Active Reduction of an Enclosed Sound Field: An Experimental Investigation

摘要

The simplest enclosed sound field, a duct with closed ends, is studied and it isexperimentally demonstrated that strategies developed for the control of sound in ducts do not perform as well as a strategy developed for the control of sound in enclosed spaces. The enclosed sound field has the simple structure of standing wave composed of two propagating waves, an incident wave from the primary source and a reflected wave from the closed end. Three control strategies for the reduction of this sound field, the acoustical virtual earth and the absorbing termination (both of which were successfully used in ducts) and the strategy of minimization of energy (developed for the control of sound in enclosed spaces), were investigated. The performance of these three strategies are experimentally implemented and compared in a test enclosure using single frequency excitation.