COMPARING RESULTS OF USING ISO 140-4:1998 TO ISO 16283-1:2014

ISO 140-4:1998 has been replaced by ISO 16283-1:2014. ISO 16283-1 introduces new approaches for source directivity, a limit of 8dB between adjacent 1/3 octave bands within the source room, a means to calculate “level difference”, and distinguishes a Default Procedure and a Low-frequency Procedure for Sound Pressure Level measurement, that are not included in ISO 140-4. For the Default Procedure, ISO 16283-1 introduces the possibility to use a "manually-scanned microphone" method, also not included in ISO 140-4. The main objective of this paper is to compare the results of using the new ISO 16283-1 approaches with results using the old ISO 140-4 approaches. This comparison provides knowledge of the change in results that may occur in the transition from ISO 140-4 to ISO 16283-1, and may be useful to help laboratories in deciding the kind of procedures that are necessary in this transition.