«Adrienne» a European method to qualify road noise barriers on site

Adrienne is a method developed in a European research project, the aim of which was the measurement on site of sound absorption and sound transmission of any road noise barrier. In order to get the impulse response of the device (absorption measurement), a M.L.S. (Maximum Length Sequence) method was selected mainly for its excellent signal/noise ratio. The introduction of a subtraction technique improves the low frequency information. For flat barriers, measurement results showed a good agreement with well-known models or other experimental methods. For non flat barriers, numerical predictions resulted in the requirement of an averaging performed on many source and receiver positions. An encouraging agreement between measurements and predictions was found. Round robin tests on a specially built platform proved a good repeatability of the method.