This standard specifies performance requirements for 3 classes of sound calibrators: class LS (Laboratory Standard), class 1 and class 2. Class LS sound calibrators are normally used only in the laboratory; class 1 and class 2 are considered as sound calibrators for field use. Conformance is demonstrated when a) measured deviations from design goals do not exceed the applicable acceptance limits and b) the uncertainty of measurement does not exceed the corresponding maximum-permitted uncertainty.