Equivalent rectangular bandwidth

For moderate sound levels and young listeners, Moore & Glasberg (1983) suggest that the bandwidth of human auditory filters can be approximated by the polynomial equation:[1] where   F   is the center frequency of the filter, in kHz, and   ERB( F )   is the bandwidth of the filter in Hz.

The approximation is based on the results of a number of published simultaneous masking experiments and is valid from 0.1–6500Hz.

The approximation is applicable at moderate sound levels and for values of   f   between 100 and 10000Hz.

[1] Using the second order polynomial approximation (Eq.1) for ERB(f) yields: where f is in kHz.

The VOICEBOX speech processing toolbox for MATLAB implements the conversion and its inverse as: where f is in Hz.