The 1400 Hz cut-off equalizes spectral contribution based on the SII importance function

Evidence

Digital finite impulse response filters of 512 coefficients were designed using the host-windowing technique (Abed and Cain 1984 ). High-pass (HP) and low-pass (LP) filters were used on the target or the masker at different attenuations (0 to 65 dB) depending on the experiment. The cut-off frequency was set to 1400 Hz for both HP and LP filters to achieve equal contribution from the pass and stop bands according to the SII band importance function (ANSI 1997 ; Dubno et al. 2005 ). — Dijk, Pim van, Physiology, Psychoacoustics and…, 3547

Categorization

• DEFINE: Defines the SII band importance function as the basis for choosing a filter cut-off frequency around 1400 Hz.
• QUESTION: Why is 1400 Hz chosen as the SII-balanced boundary, and how does this map onto real frequency-band importance for speech intelligibility?