Evaluating the uncertainty of laboratory measurements of low-frequency impact noise

Impact noise at low frequencies, specifically the third-octave bands below 100 Hz, is important to occupant reaction and are, therefore, routinely measured in field impact testing. For laboratory impact testing, the situation is less clear. Because the measured levels depend strongly on the specifics of the test chamber, it is expected that the reproducibility of low-frequency impact noise between laboratories to be poor and the translation to field measurements to be difficult. Despite these difficulties, the authors will demonstrate that it is possible to extract useful low frequency information from laboratory testing. The utility of laboratory testing for design of low-frequency impact noise is discussed.