Running on Concrete

How it's made

Source

alternating running shoes strike a rigid concrete slab at 180, 210 or 240 steps/minute. A 0.7–1.8 ms noise attack models the outsole slap, followed by forefoot loading 22–38 ms later.

Body

broad 100–650 Hz filtered contact noise models sole compression, not a pitched drum. Concrete contributes a dry 0.6–6 kHz slap with no sustained slab modes or room reflections.

Envelope

the main load decays in 45–70 ms; the softer forefoot contact lasts 20–36 ms. Toe release drags for 45–90 ms, ending within 180 ms so the flight phase remains distinct.

Spectrum

the contact low-pass falls from 2.8–6 kHz to 1.1 kHz in 45 ms; friction slides from 3.4 to 1.3 kHz as the toe leaves the ground. Broad filters avoid ringing and tonal squeaks.

Rhythm

12, 14 or 16 contacts fill four seconds, with matched left/right pairs at the loop seam. A fixed cadence preserves fast pace; per-contact force, colour and roll timing vary slightly.

Variation

alternating feet differ by 8% in colour and sit narrowly left/right. Presets vary cadence, outsole hardness, body load and scuff independently. All noise uses named seeded streams.

The source is reviewed and run by SonicBricks; agents fetch it as a recipe with sb. It is not published on this page.