Two stages of bandwidth scaling drives efficient neural coding of natural sounds
Fig 3
Example Fourier and cochlear model spectrogram decompositions for vocalizations and background environmental sounds: (A) Crackling fire, (B) owl vocalization, (C) speech, and (D) running water. Fourier-based spectrograms are shown for three different frequency resolutions (Δf = 30, 120 and 480 Hz). The Fourier spectrograms tend to have higher power and details that are more concentrated at low frequencies, while the cochlear spectrograms have spectro-temporal components and power distributions that are more evenly distributed across frequency. Black (1.6–6.4 kHz), magenta (0.4–1.6 kHz) and red (0.1–0.4 kHz) boxes for speech (C) illustrate a regions of the Fourier or cochlear spectrograms that emphasize the voicing hormonic structure, second formant, and voicing temporal periodicity, respectively.