Slope excitation can transmit low frequencies to high critical-band regions.

Evidence

Another important difference between main excitation and slope excitation is worth noting: main excitation is related to frequency by the frequency to critical-band rate relationship, while slope excitation is related to the main frequency of the main excitation producing the slope excitation. This fact is evident in excitation patterns produced by low-frequency high-level tones … The excitation produced at a critical-band rate as high as 13 Bark (2 kHz) can “vibrate” with a frequency as low as 20 Hz. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 977

Categorization

• DEFINE: Clarifies the distinction between main excitation (frequency mapped via critical-band rate) and slope excitation (tied to the main excitation’s frequency), a key model concept.