1 Scope
This document specifies an engineering method for measuring the noise emitted by road
vehicles of categories M and N by using a semi anechoic chamber with a dynamometer
installed.
The specifications are intended to achieve an acoustical correlation between testing
the exterior noise of road vehicles in a semi anechoic chamber and outdoor testing
as described in ISO 362‑1.
This document provides all necessary specifications and procedures for indoor testing
to obtain results which are comparable to typical run-to-run variations of measurements
in today’s type approval tests.
This document provides a method designed to meet the requirements of simplicity as
far as they are consistent with the reproducibility of results under the operating
conditions of the vehicle.
NOTE 1 The results obtained by this method give an objective measure of the noise emitted
under the specified conditions of test. It is necessary to consider the fact that
the subjective appraisal of the noise annoyance of different classes of motor vehicles
is not simply related to the indications of a sound measuring system. As annoyance
is strongly related to personal human perception, physiological human conditions,
culture, and environmental conditions, there is a large variation and annoyance is
therefore not useful as a parameter to describe a specific vehicle condition.
NOTE 2 If measurements are carried out in rooms which do not fulfil the requirements stated
i...