Fundamental study of measuring error caused by measuring points of sound power level using sound intensity method

摘要

In one of the error factors of the power level by sound intensity method, there is measuring error which originates in measuring points. This measuring points. This measuring error is influenced by properties of source and shape of close curved surface. In our previous paper, it was experimentally discussed that the measuring points need to measure about 24, for some vacuum cleaners. In this report, it was theoretically discussed suing dipole sources. The closed curved surface was set the sphere and the cube. As the results, if it is source with the directivity that the number of lobes are decided by kd, it can be said that the number of 24 points satisfies the measuring accuracy of JIS.