NCIDQ IDFX 2025 – 400 Free Practice Questions to Pass the Exam

The phenomenon of prolonged sound bouncing off hard surfaces is known as reverberation. Reverberation occurs when sound waves reflect off surfaces such as walls, floors, and ceilings, creating a complex sound field where multiple echoes happen over time. This results in a sustained sound that can continue even after the original noise source has stopped.

Reverberation is significant in various spaces such as auditoriums, theaters, and lecture halls, where it can enhance or hinder sound quality depending on the desired acoustics.

Absorption refers to the process where materials take in sound energy, reducing reflection and reverberation. Reflection, while related to how sound bounces off surfaces, does not fully capture the extended effect of sound lingering in a space over time. Diffusion involves the scattering of sound in various directions, which can enhance evenness of sound distribution, but does not involve the lingering effect of sound as reverberation does. Thus, reverberation correctly identifies the specific outcome of sound persistence in environments with hard surfaces.