Similar to light, the reflection of sound depends on the material, surface structure and geometry of the reflector object. Just as mirrors can increase the perceived luminance of a room, acoustic reflectors can increase the perceived loudness of a space substantially and shape the characteristics of the sound.
Urban Architecture is a strong sound reflector. The sonic impact of flat, vertical concrete surfaces or smooth glass facades is often overlooked, and seemingly simple choices of surface materials can make a big difference. On this page, we explain the mechanisms based on examples from urban situations.
In this example from Zurich, the facade of the residential building acts as an acoustic mirror for the passing train, the direct impact and the sonic reflection can clearly be distinguished.
In the second example from Bonn, the used tiling material turns the ceiling of the passage into an effective sound mirror.