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Test method for the acoustic performance of road traffic noise reducing devices

Objective

This project aims to develop a new method of measuring the sound absorption, the airborne sound insulation, and the efficiency of road traffic noise reducing devices. The method developed must overcome problems encountered during the drafting of the related standard within CEN/BTS1/TC226/WG6 (road equipments - anti-noise devices):
for part 1 of the standard, there is no satisfactory method to qualify the sound absorption of non-flat products;
for part 5 of the standard "in-situ values of absorption and insulation", the existing method (AFNOR NF-S/31-089) has limitations in the low frequency range (100-400 Hz) and cannot be used with non-flat products.
By permitting the in-situ characteristics of all types of road traffic noise reducing devices to be determined, the new test method will help to ensure the free circulation of these devices in Europe and will enable road engineers to control road traffic noise in the environment more effectively.

Work Package 1 looked at different types of signals (echo-impulse and stationary), sensors and noise sources. Three relevant types of test samples, four existing methods and three new theoretical tools were investigated. Based on the results, a method is currently developed in Work Package 2 using M.L.S. (Maximum Length Sequences) with a single loudspeaker and sound pressure sensors. A method of subtracting the incident signal should allow measurements to be made down to 100 Hz. The use of multiple sensors is being investigated both theoretically and practically in order to solve problems with non-flat products.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Acoustical Technologies
Address
215,Avenue Brugmann
1180 Bruxelles
Belgium

Participants (3)

Centre National de la Recherche Scientifique (CNRS)
France
Address
Rue Maurice Audin
69518 Vaulx-en-velin
FRAUNHOFER IAF
Germany
Address
Tullastr. 72
79108 München
UNIVERSITY OF BOLOGNA
Italy
Address
Via Zamboni 33
40126 Bologna