ABSTRACT
The resemblance in both figures is fairly good. The discrepancy for the fundamental harmonic in the frequency domain is to a considerable extent due to the errors introduced by the Hanning window. The reason for this is that the signal from the 2-microphone method is a pure one-period signal and consequently Fouriertransformed by means of a rectangular window. The signal from the anechoic method, however, consists of a number of periods demanding at least a Hanning window. For the fundamental harmonic in this case the error in magnitude is almost on the maximum level, i.e. 15 %.
