Individual variability in distortion-product cancellation grows with primary frequency separation

Evidence

The six subjects show behaviour that is similar to that of the subject whose results are outlined in Fig. 14.4. The interquartile ranges of cancellation level and cancellation phase seem to increase with increasing frequency separation of the two primaries. If the individual data sets are compared with the median values, it is clear that the individual differences are caused by a parallel shift upwards or sidewards; the general shape of the curves remains similar for all subjects. Only for the largest frequency separation of the primaries (11/ = 572 Hz) does individually different behaviour appear. Some subjects produce data that are similar to the medians; other subjects show level minima and phase jumps that make averaging a doubtful procedure. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1567