If the measured test surface temperature does not change more than 5 °C within all measurements necessary for the determination of the sound level of one set of tyres, the temperature correction may be made only on the final reported tyre rolling sound level as indicated above, utilizing the arithmetic mean value of the measured temperatures. Otherwise each measured sound level Li shall be corrected, utilizing the temperature at the time of the sound recording. There will be no temperature correction for Class C3 tyres. 4.4. In order to take account of any measuring instrument inaccuracies, the results according to paragraph 4.3. above shall be reduced by 1 dB(A). 4.5. The final result, the temperature corrected tyre rolling sound level LR(ref) in dB(A), shall be rounded down to the nearest lower whole value. Figure 1 Microphone positions for the measurement
If the measured test surface temperature does not change more than 5 °C within all measurements necessary for the determination of the sound level of one set of tyres, the temperature correction may be made only on the final reported tyre rolling sound level as indicated above, utilizing the arithmetic mean value of the measured temperatures. Otherwise each measured sound level Li shall be corrected, utilizing the temperature at the time of the sound recording. There will be no temperature correction for Class C3 tyres. 4.4. In order to take account of any measuring instrument inaccuracies, the results according to paragraph 4.3. above shall be reduced by 1 dB(A). 4.5. The final result, the temperature corrected tyre rolling sound level LR(ref) in dB(A), shall be rounded down to the nearest lower whole value. Figure 1 Microphone positions for the measurement
R117r4e.docx