Understanding Echo
An echo is a distinct sound reflection that reaches the listener after the direct sound has faded. It occurs when a sound wave hits a distant surface and bounces back, arriving as a separate, delayed repetition of the original sound. For an echo to be perceived as distinct, the reflecting surface must typically be at least 17 meters (56 feet) away from the sound source and listener, allowing a time delay of at least 0.1 seconds.
Understanding Reverberation
Reverberation refers to the persistence of sound in a particular space after the original sound is produced, resulting from multiple reflections bouncing off surfaces within that space. Unlike a single, distinct echo, reverberation involves a complex pattern of overlapping reflections that gradually decay in amplitude, creating a sense of sustained sound rather than individual repetitions.
Key Distinctions
The primary difference lies in their perception and the nature of sound reflections. An echo is perceived as one or more distinct repetitions of the original sound, requiring significant distance to separate the direct and reflected waves. Reverberation, however, is a continuous, decaying wash of overlapping reflections, making individual reflections indistinguishable and creating a 'liveliness' to the sound.
Practical Examples
Imagine shouting in a large, empty canyon; the clear, delayed repetition you hear is a distinct echo. Conversely, the prolonged decay of sound in a concert hall or a large, unfurnished room after someone claps is an example of reverberation, where countless rapid reflections blend together to extend the sound's presence.