Sound
Echo
Noise
Reverberation
- Reverberation: Multiple blended, random reflections of a sound wave after the sound source has ceased vibrating. Also called reverb and reverberant sound.
- Reverberation can be defined as the persistence of sound after it has been produced. A sound formed in a large-sized hall will be reflected from the walls repeatedly until it is decreased to the point where it is not audible. Excessive reverberation is highly unwanted in an auditorium or large-sized hall. To reduce reverberation, the ceiling and walls in the auditorium are typically covered with sound-absorbent materials such as compressed rough plaster and fiberboard.
- Echo: Sound reflections delayed by 35 ms or more that are perceived as discrete repetitions of the direct sound.
- The sound heard after reflection from a rigid surface such as a cliff or a wall is called echo. An echo can be heard if the distance between the source of sound and the reflecting surface is greater than or equal to 17m and the time difference between direct and reflected sound is greater than 0.1s. The echo is used by bats and dolphins to detect obstacles in their way, navigation, etc.
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