Motor Racing Vehicles - Measurement Methods

2 Basic principles

The following terminology is used in this report:

Noise. General term characterising sound from racing vehicles.
Noise level. A-weighted sound pressure level in dB re. 20µPa. (LpA). The instantaneous noise level can be determined with integration time corresponding to FAST
(L_pAF) or SLOW (L_pAS).
Maximum noise level. The maximum value of L_pAF measured during passby of a single racing vehicle (L_pAmaxF).
Energy equivalent sound pressure level, L_Aeq,T is the A-weighted energy mean of the noise level averaged over the measurement period.

Formel

Noise immission. Energy equivalent A-weighted sound pressure level in dB re. 20µPa, (L _AeqT), measured or predicted over the time interval T (normally 1 hr.), at some distance from a racetrack, typically at dwellings.
Noise emission. Sound power level (L _W) in dB re. 1pW characterising the noise radiation from a vehicle. The noise emission can be A-weighted (L _WA), or expressed in frequency bands, usually 1/3 or 1/1-octave bands. For declaration purposes, the noise emission can be an average level for a group of vehicles. For monitoring purposes, the noise emission is determined for a single vehicle.
Ground correction. A correction term characterising the influence upon the sound propagation due to the acoustic properties of the ground between a noise source and a microphone. The ground correction is an important part of the noise emission determination as well as of the prediction of the noise immission.