FREQTOAUD - Converts frequencies (Hz) to auditory scale units.
- aud = freqtoaud(scale,freq);
FREQTOAUD(scale,freq) converts values on frequency scale (measured in Hz) to
values on the selected auditory scale. The value of the parameter
scale determines the auditory scale:
The mel scale is a perceptual scale of pitches judged by
listeners to be equal in distance from one another. The
reference point between this scale and normal frequency
measurement is defined by equating a 1000 Hz tone, 40 dB above
the listener's threshold, with a pitch of 1000 mels.
The mel-scale is defined in Stevens et. al (1937).
distance of 1 on the bark scale is known as a critical
band. The implementation provided in this function is
described in Traunmuller (1990).
A distance of 1 erb is equal to the equivalent rectangular
bandwidth of the auditory filters at that point on the
frequency scale. The scale is normalized such that 0 erbs
corresponds to 0 Hz. The width of the auditory filters were
determined by a notched-noise experiment. The erb scale is
defined in Glasberg and Moore (1990).
This is the original defintion of the erb scale given in
Moore. et al. (1983).
B. Glasberg and B. Moore.
Derivation of auditory filter shapes from notched-noise data.
Hearing Research, 47(1-2):103, 1990.
B. Moore and B. Glasberg.
Suggested formulae for calculating auditory-filter bandwidths and
The Journal of the Acoustical Society of America, 74:750, 1983.
S. Stevens, J. Volkmann, and E. Newman.
A scale for the measurement of the psychological magnitude pitch.
The Journal of the Acoustical Society of America, 8:185, 1937.
Analytical expressions for the tonotopic sensory scale.
The Journal of the Acoustical Society of America, 88:97, 1990.
Subdivision of the audible frequency range into critical bands
The Journal of the Acoustical Society of America,
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