28 spectral-channel (high-dimensional) envelope representation of the nursery rhyme sentence "Twinkle twinkle little star".

The bottom panel (grey) shows the original sound pressure waveform of the sentence, where the x-axis indicates time and the y-axis indicates signal amplitude. The top panel shows the corresponding high-dimensional set of 40 Hz low-pass filtered Hilbert envelopes. The envelopes for the 28 ERBN-spaced spectral channels are plotted upwards in order of increasing acoustic frequency, where each coloured line indicates a different spectral channel (i.e. blue = low frequency, red = high frequency). The vertical height of each coloured line indicates the amplitude of the envelope at each point in time.