Cochlear spiral spectrogram — mapping audio to a Fermat spiral

I built a music visualization system in Python that maps audio frequencies onto a Fermat spiral — mimicking the frequency layout of the human cochlea.

The approach:

  • 381 log-spaced frequency bins via FFT (scipy)
    • ISO 226 equal-loudness normalization
      • Chromesthesia color mapping (frequency to hue)
        • 60 FPS rendering with temporal features: melodic trails, rhythm pulses, harmonic auras
      • The fascinating part: harmonic intervals create visually symmetric patterns on the spiral. You can literally see the difference between major and minor chords.
    • I think this could be interesting for the TouchDesigner community — especially for anyone working with audio-reactive visuals. The core algorithm could potentially be ported to a GLSL TOP.
  • Video: https://www.youtube.com/watch?v=66RiYBl7aQY

More examples: youtube.com/@NivDvir-ND