Advancements in Sound Reflection and Airborne Sound Insulation Measurement on Noise Barriers


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.

Share and Cite:

P. Guidorzi and M. Garai, "Advancements in Sound Reflection and Airborne Sound Insulation Measurement on Noise Barriers," Open Journal of Acoustics, Vol. 3 No. 2A, 2013, pp. 25-38. doi: 10.4236/oja.2013.32A004.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] CEN/TS 1793-5, “Road Traffic Noise Reducing Devices— Test Method for Determining the Acoustic Performance— Part 5: Intrinsic Characteristics—In Situ Values of Air-borne Sound Reflection and Airborne Sound Insulation,” 2003.
[3] EN 1793-1, “Road Traffic Noise Reducing Devices— Test Method for Determining the Acoustic Performance— Part 1: Intrinsic Characteristics of Sound Absorption,” 1997.
[4] EN 1793-2, “Road Traffic Noise Reducing Devices— Test Method for Determining the Acoustic Performance— Part 2: Intrinsic Characteristics of Airborne Sound Insulation,” 1997.
[5] ADRIENNE Project Team, SMT Project MAT1-CT94049 Final Report, 1998.
[6] M. Garai and P. Guidorzi, “European Methodology for Testing the Airborne Sound Insulation Characteristics of Noise Barriers in Situ: Experimental Verification and Comparison with Laboratory Data,” Journal of the Acoustical Society of America, Vol. 108, No. 3, 2000, pp. 1054-1067. doi:10.1121/1.1286811
[7] G. Watts and P. Morgan, “Measurement of Airborne Sound Insulation of Timber Noise Barriers: Comparison of in Situ Method CEN/TS 1793-5 with Laboratory Method EN 1793-2,” Applied Acoustics, Vol. 68, No. 4, 2007, pp. 421-436. doi:10.1016/j.apacoust.2006.03.001
[8] M. Garai and P. Guidorzi, “In Situ Measurements of the Intrinsic Characteristics of the Acoustic Barriers Installed along a New High Speed Railway Line,” Noise Control Engineering Journal, Vol. 56, No. 5, 2008, pp. 342-355. doi:10.3397/1.2969244
[9] M. Conter, M. Haider and R. Wehr, “Aluminium Noise Barriers and Added Devices: A Case Study Using the European Standard for in-situ Measurements,” Proceedings of Inter-Noise 2009, Ottawa, 23-26 August 2009, pp. 1260-1271.
[10] M. Garai P. Guidorzi and L. Barbaresi, “Progress in Sound Reflection Measurements on Noise Barriers in Situ,” Proceedings of Inter-Noise 2012, New York, 19-22 August 2012, pp. 1-10.
[11] P. Guidorzi and M. Garai, “Reflection Index Measurement on Noise Barriers with the Adrienne Method: Source Directivity Investigation and Microphone Grid Implementation,” Proceedings of Inter-Noise 2011, Osaka, 4-7 September 2011, pp. 1-6.
[12] P. Guidorzi and M. Garai, “Signal Analysis in the Sound Absorption Measurement Procedure: The Importance of Time Subtraction and Reference Surface Corrections,” Proceedings of Acoustics-08, Paris, 29 June-4 July 2008, pp. 1755-1760.
[13] M. Garai, P. Guidorzi and E. Schoen, “Assessing the Repeatability and Reproducibility of in Situ Measurements of Sound Reflection and Airborne Sound Insulation Index of Noise Barriers,” Proceedings of AIA-DAGA 2013, Meran, 19-21 March 2013, pp. 1-4.
[14] P. Robinson and N. Xiang, “On the Subtraction Method for in-situ Reflection and Diffusion Coefficient Measurements,” Journal of the Acoustical Society of America, Vol. 127, No. 3, 2010, pp. EL99-EL104. doi:10.1121/1.3299064
[15] P. Guidorzi, J. Klepacek and M. Garai, “On the Repeatability of Reflection Index Measurements on Noise Barriers,” Proceedings of EuroNoise 2012, Prague, 10-13 June 2012, pp. 1314-1319.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.