An experimental analysis method for the incident sound field using propagation mode expansion: Study on the incident sound field in the insulation performance measurement for partition walls. part 1

Abstract

Abstract In the measurement of the level difference between dwelling rooms, the low‐frequency modal density of the source room is not high enough for the incident sound field to be assumed as a random incidence, and the sound field is expected to be strongly influenced by the standing waves of the room modes. In this paper, an experimental method is proposed to analyze the characteristics of the incident sound fields in dwelling rooms, where the propagation mode expansion is applied to the complex sound pressure observed on the two layers of planar microphone array. The proposed method is applied to numerical models to simulate the incident sound fields to obtain information on its accuracy and application limitations, and the applicability of the method to ordinary rooms is discussed. In addition, the effect of room absorption on incident characteristics is demonstrated using the proposed method.

Keywords

• sound insulation measurement
• incident sound field
• sound field decomposition
• propagation mode
• directivity