Asymmetric pre- and post-masking durations distort symmetric reversals in FM masking patterns.

Evidence

The two curves “2” and “6” should be identical if premasking and post masking were to behave similarly. Because post masking lasts much longer than premasking, these differences are to be expected. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 547