Curved surfaces can focus reflected sound and enhance its intensity

Evidence

The intensity levels of the early reflections are affected by both the dis­ tance and the surface from which they are reflected. In general most sur­ faces absorb some of the sound energy and so the reflection is weakened by the absorption. However, it is possible to have surfaces which “focus” the sound, as shown in Figure 6.4, and in these circumstances the intensity level at the listener will be enhanced. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1737

Categorization

• SHARE: Architectural acoustics fact about focusing surfaces — the reason some concert venues have ‘hot spots’ or whisper galleries; a specific engineering-type person would enjoy this.