Vibration-controlled modules for use in active segmented partitions

Abstract

Active segmented partitions (ASPs) have become an important topic in the research of active sound transmission control (ASTC). Many ASTC applications require lightweight partitions, high transmission loss over a broad frequency range, and applicability to a variety of source and receiving space conditions. This paper provides theoretical, numerical, and experimental evaluations of specific ASP module configurations used to satisfy these requirements. The control objective for each is to induce global vibration control of its various transmitting surfaces through direct minimization of the normal vibration of its principal transmitting surface. Normal-incidence transmission loss estimates are based on equivalent circuit analysis and corresponding experimental measurements are made using plane wave tube techniques. The paper explains why characteristic single diaphragm configurations are unable to use this strategy effectively. It also discusses two dual diaphragm configurations that use the control scheme particularly well to produce efficient global control of their transmitting surfaces and achieve very high transmission loss over a broad frequency range. The designs facilitate incorporation into full ASP arrays and satisfy other useful criteria.