Abstract: The noise of home appliances is relatively lower than that of other kinds of machines, so background noise is one of the most important factors affecting the accuracy of the test. In actual testing, background noise cannot be completely eliminated, so it needs to be measured and processed to obtain the final test result. The international standard IEC 6070.1, IOS 3745 and the Chinese standard GB 6882 for sound power measurements have requirements for background noise. In the two latest versions, in addition to the relative criterion, an absolute criterion has been proposed. Based on the interpretation of the three editions of the standard, the article analyzes and explores the selection conditions of the latest relative and absolute criteria.

Key words: Noise test, Background noise, Environmental background noise, Electrical Noise, Test standard, Relative criterion, Absolute criterion