Year-end Sale % OFF 
Abstract
The in-situ measurement of sound reflection and airborne sound insulation characteristics of a noise barrier in Europe are currently performed following the CEN/TS 1793-5 European standard guidelines (last revision published in 2003 [1]). After some years a large number of barriers measured, the original method has been significantly enhanced and validated in the frame of the EU funded QUIESST project, WP3 [2]. The sound reflection measurement method has been improved using a square 9-microphone grid not rigidly connected to the loudspeaker, an optimized alignment algorithm of free-field and reflected impulse responses, including fractional step shifts and least squares estimation of the best relative position, and a correction for geometrical divergence and sound source directivity. Each single measurement is then validated by means of the Reduction Factor calculation. The airborne sound insulation measurement method has not been markedly changed since 2003, because the procedure is robust and easily applicable as it is, but some problems may still be encountered when measuring highly insulating noise barriers, due to a poor signal to noise ratio of the transmitted impulse response. In those cases it is difficult to realize just after the measurement whether the obtained data are valid or not. A method, applicable on site, to overcome this problem is described here. It is based on the Signal to Noise Ratio estimation of critical parts of the acquired impulse responses and gives a strong validation criterion.
Highlights
Noise barriers can be very different for shape and materials, and every day new ones are appearing on the market
The sound reflection measurement method has been improved using a square 9-microphone grid not rigidly connected to the loudspeaker, an optimized alignment algorithm of free-field and reflected impulse responses, including fractional step shifts and least squares estimation of the best relative position, and a correction for geometrical divergence and sound source directivity
It is based on the Signal to Noise Ratio estimation of critical parts of the acquired impulse responses and gives a strong validation criterion
Summary
Noise barriers can be very different for shape and materials, and every day new ones are appearing on the market. In the laboratory sound absorption is tested placing a 10 m2 sample on the floor of a reverberation room according to the European standard EN 1793-1 [3]. Airborne sound insulation is tested placing a 10 m2 sample between two reverberation rooms according to the European standard EN 1793-2 [4]. The measurements are done almost as in building acoustics These laboratory methods imply that the samples are tested in a diffuse sound field, i.e. the sound waves arrive on the test sample from all angles of incidence. Laboratory samples are not representative of real installation conditions and workmanship This laboratory methods do not allow an easy control of the long term acoustic performances of noise barriers years after years, as is needed in order to assess their sustainabilities.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
