Envelope

aud_space_bw(fmin, fmax[, bw, scale])	Auditory scale points specified by bandwidth.
aud_to_freq(aud[, scale])	Convert auditory units at the auditory scale to frequency (Hz).
gammatone(audio, fs[, fs_inter, fs_target, ...])	Compute the envelope of audio using a gammatone filterbank.
rms(audio, fs[, fs_inter, fs_target])	Compute the envelope of the audio as the root mean square (RMS) of the signal.
erb_space_bw(fmin, fmax[, bw])	Auditory scale points specified by bandwidth.
freq_to_aud(freq[, scale])	Convert frequencies (Hz) to auditory units at the auditory scale.