Motor Racing Vehicles - Measurement Methods

3 Existing measurement methods

For the last two decades the following noise measurement methods have been widely used in Denmark.

L_pA monitoring method used by the motor sport organisations. The steady noise is measured close to a stationary vehicle at a specified engine revolution. As the engine is unloaded, and not necessarily running at realistic maximum racing speed, this method correlates poorly with the immission relevant noise emission.
L_pAmaxF monitoring method used by the motor sport organisations for karting. The noise is measured close above a passing vehicle during normal racing. This method correlates relatively well with the immission relevant noise emission, but is only implemented for karting vehicles and not for general use
1/3-octave declaration method used by acoustic laboratories for measurement of the noise emission relevant for noise immission. This is a passby method where the sound power level is determined at realistic racing conditions. The noise level is integrated during the passby, and a relative complicated integrated ground correction term is applied in order to determine the noise emission. Therefore, a new declaration method using a less elaborate ground correction term, will facilitate more frequent declaration measurements, and thus a more updated database of noise emission values for racing vehicles. This method is further described in ref. 1.