What term describes a buzzing sound created by repeated echoes between two reflective surfaces?

The term that describes a buzzing sound created by repeated echoes between two reflective surfaces is flutter. This phenomenon occurs when sound waves reflect back and forth between surfaces that are positioned closely together, causing a rapid modulation of sound. As the echoes overlap, they can interfere with each other, sometimes amplifying certain frequencies while diminishing others, which results in a characteristic buzzing or fluttering sound.

In environments with parallel reflective surfaces, such as a narrow hallway or an empty room, flutter can become quite pronounced. This effect is especially noticeable with high-frequency sounds, which can create the perception of a continuous buzzing due to the quick succession of reflections. Understanding flutter is important in acoustics, especially in designing spaces for optimal sound quality.

The other terms listed do not capture this specific acoustic effect. For example, a standing wave refers to a wave that remains in a constant position and does not propagate through a medium, which does not involve the same type of repeated echoing. Thus, flutter is the most accurate term for describing the buzzing sound resulting from echoes between reflective surfaces.