Noise Barrier Diffraction — Acoustic Shadow Map

Roadside and railway noise barriers work by forcing sound to diffract over their top edge, which costs the wave energy in proportion to how much extra distance that detour adds relative to a wavelength. This simulation renders a live 3D "noise map": a grid of bars whose height and colour encode the modelled sound level everywhere around a barrier, computed point-by-point from the Kurze–Anderson insertion-loss formula and its Fresnel number. Drag the barrier height, source frequency, and source/receiver distance sliders to watch the acoustic shadow zone grow, shrink, or vanish entirely once the receiver's line of sight clears the wall — the same trade-offs a noise-control engineer weighs when specifying a barrier height for a given traffic frequency spectrum.