In one embodiment of the present invention, an apparatus for characterizing an acoustic impedance of an engineering component acoustically coupled to an acoustic waveguide includes: a pressure measurement apparatus adapted to be moved and to be disposed to measure pressure signals, the pressure signals being measured at respective ones of a plurality of predetermined locations along the acoustic waveguide; an exciter adapted to excite the acoustic waveguide with an excitation signal; a data collection module adapted to incorporate the pressure signals from the pressure measurement apparatus into a pressure signal set; a transform module adapted to transform the pressure signal set to a frequency domain set; a wave shape identifier adapted to identify a plurality of wave shape parameters from the frequency domain set; and a statistical computer adapted to compute from the frequency domain set a statistical measure for the wave shape parameters, the statistical measure being selected from the group consisting of residual variance, correlation coefficient, F-statistic, p-statistic, and confidence interval.