AUDFILTBW - Bandwidth of auditory filter

Usage

bw = audfiltbw(fc)

Description

audfiltbw(fc) returns the critical bandwidth of the auditory filter at center frequency fc defined in equivalent rectangular bandwidth. The function uses the relation:

\begin{equation*} bw = 24.7 + \frac{fc}{9.265} \end{equation*}

as estimated in Glasberg and Moore (1990). This function is also used when the original ERB scale ('erb83') is chosen.

audfiltbw(fc,'bark') returns the critical bandwidth at fc according to the Bark scale using the relation:

\begin{equation*} bw = 25 + 75 ( 1+1.4\times10^{-6} fc^2 )^{0.69} \end{equation*}

as estimated by Zwicker and Terhardt (1980).

For the scales 'mel', 'mel1000', 'log10' and 'semitone', no critical bandwidth function is usually given. Following the example of the equivalent rectangular bandwidth (associated with the ERB scale), we use the derivative of the inverse of the scale function F_{Scale}, evaluated at F_{Scale}(fc), i.e.

\begin{equation*} bw = (F_{scale}^{-1})'(F_{scale}(fc)) \end{equation*}

References:

E. Zwicker and E. Terhardt. Analytical expressions for criticalband rate and critical bandwidth as a function of frequency. The Journal of the Acoustical Society of America, 68(5):1523--1525, 1980. [ DOI | http ]

B. R. Glasberg and B. Moore. Derivation of auditory filter shapes from notched-noise data. Hearing Research, 47(1-2):103, 1990.