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BS EN 1793-4:2015 Road traffic noise reducing devices. Test method for determining the acoustic performance - Intrinsic characteristics. In situ values of sound diffraction >
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BS EN 1793-4:2015 Road traffic noise reducing devices. Test method for determining the acoustic performance - Intrinsic characteristics. In situ values of sound diffraction, 2015
- Contents Page
- Foreword
- Introduction
- 1 Scope
- 2 Normative references
- 3 Terms, definitions and symbols [Go to Page]
- Table 1 – Symbols and abbreviations
- 4 Sound diffraction index difference measurements [Go to Page]
- Table 2 – Minimum values of the Sound Insulation Index of the reference wall, measured according to EN 1793–6, tolerance ± 0,5 dB
- Table 3 – Minimum values of the sound absorption coefficient for the absorptive treatment of the reference wall, measured in reverberation room, tolerance ± 0,05 [Go to Page]
- Figure 1 ― Source and microphone positions in a vertical cross section of the test construction without added device
- Figure 2 ― Source and microphone positions in a top view of the test construction without added device
- Figure 3 ― Microphone positions in a vertical back view from receiver side of the test construction without added device
- Figure 4 ― Source and microphone positions in a vertical cross section of the test construction with added device
- Figure 5 ― Source and microphone positions in a top view of the test construction with added device
- Figure 6 ― Microphone positions in a vertical back view from receiver side of the test construction with added device
- Figure 7 ― Source and microphone positions for the free-field measurement in a vertical cross section (example given for source position S1 and microphone position M1)
- Figure 8 ― Maximum horizontal dimension of the added device [Go to Page]
- Figure 9 ― Sketch representing the essential components of the measuring system [Go to Page]
- Figure 10 ― The Adrienne temporal window, with the marker point MP [Go to Page]
- Figure 11 — Example of application of the Adrienne temporal window to the diffracted component of an impulse response [Go to Page]
- Figure 12 ― Low frequency limit of sound diffraction index measurements as a function of the height of the test construction for the obligatory source position S1 (normal incidence) [Go to Page]
- 5 Measurement uncertainty
- 6 Measuring procedure [Go to Page]
- Annex A (informative) Indoor measurements for product qualification
- A.1 General
- A.2 Parasitic reflections
- Figure A.1 ― Clearance zone in a vertical cross section of the reference wall with added device
- A.3 Reverberation time of the room
- Annex B (informative) Measurement uncertainty
- B.1 General
- B.2 Expression for the calculation of sound diffraction index
- B.3 Contributions to measurement uncertainty
- Table B.1 — Information to derive the overall uncertainty
- B.4 Expanded uncertainty of measurement
- B.5 Measurement uncertainty based upon reproducibility data
- Bibliography [Go to Page]