Acoustic Reflection Dynamics: Why Echoes Amplify in Mountainous Terrain

为什么回声在山谷里更明显

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Echo clarity depends not on raw distance alone, but on the ratio of direct-path attenuation to reflected-path coherence—a ratio optimized in parallel-walled canyons.
Mountain rock faces act as broadband reflectors above 100 Hz, preserving speech intelligibility better than urban concrete, which scatters mid-frequency energy.

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