Where do the shortest reverberation times tend to be?

• A. Open fields and soundproof rehearsal rooms
• B. Cathedrals and large concert halls
• C. The ocean
• D. Busy urban streets

Answer: (A)

Reverberation time is how long it takes for sound to decay after you stop producing it. The shorter this time, the quicker the sound dies away. This happens when there are few boundaries to reflect the sound and when surfaces absorb most of the energy. An open field has almost no walls or ceilings to bounce sound back, so the energy quickly disperses into the air, leading to a very short decay. A soundproof rehearsal room is purposely lined with absorbent materials and sealed from outside noise, so reflections are minimized and the sound dies away rapidly. In contrast, cathedrals and large concert halls have lots of hard, flat surfaces and large volumes, which bounce sound around and extend the decay time. The ocean and busy urban streets involve complex reflections, but they don’t provide the quick, absorption-dominated decay you get in an open field or a well-treated room. So the environments with the shortest reverberation times are open fields and soundproof rehearsal rooms.