Far-Field Measurements of the Acoustic Properties of Noise Barriers

Measuring the acoustic properties of noise reducing devices is an important prerequisite for efficient noise protection along major transport routes. While a well-defined measurement procedure for the determination of the near-field absorption properties of noise barriers exists in the form of CEN/TS 1793-5, no method for the determination of the far-field reflection properties is standardised. In the work package 2 of the QUIESST project, funded by the European Union in FP7, one of the topics under investigation is the relation between near-field measurement results obtained by impulse-response measurements of the type described in CEN/TS 1793-5 and their validity in the far-field. In this paper, the measurement principle as well as first results of these far-field measurements will be described.