Post masking outlasts premasking and asymmetrically distorts threshold patterns.

Evidence

Because post masking lasts much longer than premasking, these differences are to be expected. For a modulation frequency of 8 Hz, this effect becomes more pronounced leading to differences of almost 20 dB in masked threshold for the positions indicated by “2” and “6” at lower critical-band rates. The difference is not as large at higher critical-band rates because of the relatively shallow upper slope of the masking pattern. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 547

Categorization

• DEFINE: Clarifies the pre-masking vs post-masking asymmetry as the cause driving the two curves’ divergence.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 547
• XREF: connects to: Postmasking can last up to 200 milliseconds after a masker ends — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 992; Temporal masking depth is less than envelope modulation depth due to postmasking — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1423; Masked threshold shape changes with masker level, becoming more asymmetric at high levels (+2 more)

Broader Connections

• Masking effectiveness depends on masker-signal power, frequency, and timing relationships #expands (0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 461