Secondary Paths Analysis of an Active Casing Placed at a Wall

The active casing approach is to reduce device noise by controlling the vibration of its casing. Its efficiency was confirmed by the authors in laboratory experiments, and it was reported in previous publications. However, the casing was distant from walls of the enclosure. Now, a new configuration is considered, when the casing is placed at a wall, and the actuators mounted on the casing from the side of the wall are also employed to actively reduce the emitted noise. In such a configuration the acoustic reflection from the wall is intentionally used. The considered wall is smooth and rigid, thus it is highly acoustically reflective. In this paper, a preliminary experimental investigation of such concept is presented. The primary and secondary paths analysis is given. Advantages and limits of the proposed approach are pointed out and discussed.