1.1   This International Standard specifies methods for measuring the sound pressure levels on a measurement surface enveloping a source, and for calculating the sound power level produced by the source. It gives requirements for the test environment and instrumentation, as well as techniques for obtaining the surface sound pressure level from which the Α-weighted sound power level of the source and octave or one-third octave band sound power levels are calculated. This method may be used to perform acceptance tests.