Measurement of the performance of sound level meters using IEC 61672-3:2006

IEC 61672-3:2006 provides the first internationally agreed methods for measuring the performance of individual sound level meters (SLM). Pattern approval tests are specified in IEC 61672-2, but are in practice only performed in countries where legal requirements exist for testing a model of SLM before it may be sold. A calibrated sound calibrator is applied in order to determine the overall sensitivity at a reference level at a single frequency. The indicated sound level with no input signal is noted; this corresponds to the level of self-generated noise in the SLM. The indicated peak C sound level in response to single cycle and half cycle sinusoidal electrical signals is measured and compared with the theoretical ideal response. IEC 61672-3 should be recommended for use in Canada with appropriate guidance on its use with respect to older SLMs.