Shepard Tone audio spectrum visualization (constant Q transform)

Moving visualization of the Shepard tone audio spectrum. Audio is from a public domain source released in 2012. The Shepard Tone creates the feeling of constant rising but without ever reaching a destination. It’s often used to create a feeling of suspense. As you can see, multiple rising tones are played, but as the tones reach the high end of the spectrum (right side of the video), they fade out, and other lower tones are added. This visualization was created with ffmpeg’s showcqt filter. FFMpeg’s description of the showcqt filter: “Converts input audio to a video output representing frequency spectrum logarithmically using Brown-Puckette constant Q transform algorithm with direct frequency domain coefficient calculation (but the transform itself is not really constant Q, instead the Q factor is actually variable/clamped), with musical tone scale, from E0 to D#10.“ #showcqt