Reduction of Sound Transmission by Active Control of the Incident Sound to the Wall

Abstract

We propose a reduction method of sound transmission by active control of the incident sound to the wall. For the method, we developed the thin and the light type active transmission loss control module for reduction of the incident sound to the wall. The active transmission loss control module is composed of piezoelectric loudspeakers, an error microphone, and a single input-single output analog feedback controller. The active transmission loss control module can reduce the sound transmission with simple system more than ever. Because each of the active transmission loss control modules are enabled as the feedback controller which became respectively independent even if more than one are arranged. This paper shows the feature of basic concept and the active transmission loss control module. Furthermore, we report the result of the experiment which supposes the case where the active transmission loss control modules are applied to noise reduction inside the railroad vehicle.