Distortion curves are conventionally plotted under the corresponding excitation frequency of the measured fundamental. Interpretation of results can be misleading due to the influence that the passband shape and amplitude irregularities of the fundamental response have on the distortion responses. By ‘amplitude normalizing’ the distortion responses to the measured fundamental response before plotting them at the excitation frequency, distortion graphs become easier to interpret for diagnostic purposes. In addition, the distortion curves become insensitive to room reflections in the measured responses.
Authors: Steve Temme
Presented at the 94th AES Convention, Berlin, 1993