Frequency-modulated maskers produce two masking peaks where instantaneous frequency crosses the test tone twice

Evidence

At test-tone frequencies of 1200 and 1450 Hz, the pattern shows two peaks for lower modulation frequencies, indicating that the masker’s instantaneous frequency surpasses the frequency of the test-tone burst twice within the period of modulation. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 540

Categorization

• DEFINE: Clarifies the mechanism: a two-peak temporal masking pattern arises precisely when the F-M masker crosses the test-tone frequency twice per modulation cycle.