# Maekawa explorer > Explore acoustic diffraction over a barrier: geometry → Fresnel number → Maekawa attenuation. Practice: acustica Field: ambientale Status: Tool Tag: ISO 9613-2, Maekawa, Diffrazione Method, assumptions and limits: Page: --- Interactive demonstrative tool for single-edge (knife-edge) diffraction. From barrier height, source-barrier-receiver distances and frequency it computes the path difference δ, the Fresnel number N and the Maekawa attenuation (analytic approximation of the Maekawa curve, 10log10(3+20N), clamped at 25 dB by the implementation), with a side diagram and an Att(N) curve. Shares the acoustic-physics library with the Acoustic map and the Barrier calculator. This file is a **descriptor**, not the tool's documentation: it says what the tool computes and by what method, in summary. Formulas, assumptions, validity conditions and limits are in the wiki linked above. The tool runs in the browser at the page given.