Repeatability and Reproducibility of &lt;I&gt;In Situ&lt;/I&gt; Measurements of Sound Reflection and Airborne Sound Insulation Index of Noise Barriers

Garai, Massimo; Schoen, Eric D.; Behler, Gottfried; Bragado, Beatriz; Chudalla, Michael; Conter, Marco; Defrance, Jérôme; Demizieux, Patrick; Glorieux, Christ; Guidorzi, Paolo

doi:10.3813/aaa.918797

Cited by 15 publications

(13 citation statements)

References 11 publications

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“…Also, in situ measurements assume a directional sound field compared to a diffuse field in the case of laboratory measurements, since the former is more realistic. Thus, results are comparable but not identical [29,30]. In situ methods use the same principles and equipment for both RI and SI measurements.…”

Section: Methodsmentioning

confidence: 99%

Sound Insulation and Reflection Properties of Sonic Crystal Barrier Based on Micro-Perforated Cylinders

et al. 2019

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A sonic crystal barrier, consisting of empty micro-perforated cylindrical shells, was built on the campus at the Universitat Politècnica de València in 2011 and characterised by using a non-standardised measurement technique. In this paper, the sonic crystal barrier, upgraded with rubber crumb inside the micro-perforated cylindrical shells, was characterised by using standardised measurement techniques according to EN 1793-5 and EN 1793-6. As a result of the characterisation, sound insulation properties of the barrier were shown to be a combination of the absorptive properties of the individual building units and the reflective properties of their periodic distribution. In addition, its performance was compared with a similar barrier consisting of rigid polyvinyl chloride (PVC) cylinders, which was recently characterised using the same standardised techniques. In comparison with the barrier based on PVC cylinders, the barrier investigated here produced a broadband enhancement of the sound insulation and lower reflection indices in the targeted frequency range. It was also shown that the influence of leakage under the barrier and the width of the temporal window on sound insulation was negligible. While EN 1793-5 and 1793-6 allow a direct comparison of the performance of different noise barriers, the applicability to this new type of barriers requires further investigation.

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Section: Methodsmentioning

confidence: 99%

Sound Insulation and Reflection Properties of Sonic Crystal Barrier Based on Micro-Perforated Cylinders

et al. 2019

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“…Impulse responses are measured using an MLS signal, which is exactly repeatable and can give a strong background immunity [13].…”

Section: The Adrienne Measurement Methods For Sound Reflectionmentioning

confidence: 99%

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

Guidorzi¹,

Garai²

2013

OJA

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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.

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“…This study presents some series of sound insulation and sound reflection measurements repeated 10 times on the same panel of a road traffic noise barrier installed on the A22 motorway near Verona Nord (IT). The measurements were made both with the UNIBO measurement system (tested comparatively during an international round robin test [4], and therefore to be considered here as a "reference") and with the new suspended system supplied by A22, repositioning the system for each new measurement. As shown in the following, the fixed and stable spacing of all moving parts of the A22 system allows to obtain highly repeatable measurement results.…”

Section: Introductionmentioning

confidence: 99%

Advancement of the European Method for In-Situ Measurements on Road Traffic Noise Barriers

Garai,

Guidorzi,

Osele

et al. 2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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The EN 1793-5 and -6 method for measuring the intrinsic acoustic characteristics of noise barriers along motorways (a.k.a. Adrienne method) has been in use for many years and has proven to be robust and provide highly repeatable results. However, some aspects of the method can still be improved. For example, when measuring along a motorway open to traffic or when the entire length of the barrier needs to be evaluated, measurements need to be made quickly and efficiently; on the other hand, accurately positioning the equipment may be time-consuming. Therefore, Autostrada del Brennero and University of Bologna developed a frame for the measuring equipment, to be quickly transported on the test site and positioned with a crane truck. The first results seem very encouraging, however, a detailed study of the repeatability that can be expected during a full-day measurement session on the field is still lacking. This study has been done and is presented in this paper, where the new system is compared with the standard system used at University of Bologna to make the background study for EN 1793-5 and EN 1793-6. Repeated sequences of in-situ measurements have been done with both systems on the same noise barriers and the standard deviation of repeatability has been derived. It is concluded that the new rigid supporting frame has a better standard deviation of repeatability compared to a state-of-the-art equipment.

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Repeatability and Reproducibility of <I>In Situ</I> Measurements of Sound Reflection and Airborne Sound Insulation Index of Noise Barriers

Cited by 15 publications

References 11 publications

Sound Insulation and Reflection Properties of Sonic Crystal Barrier Based on Micro-Perforated Cylinders

Sound Insulation and Reflection Properties of Sonic Crystal Barrier Based on Micro-Perforated Cylinders

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

Advancement of the European Method for In-Situ Measurements on Road Traffic Noise Barriers

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