echo and reverberationare wave phenomena that are related to thereflectioninsound wavesand with the necessary time interval for the perception of the sound reflected by any obstacle.Reverb is a phenomenon that should be avoided in places where you want to perform musical recordings. The echo, in turn, is used in the animal echolocation.
sound persistence
Sound persistence is the minimum time interval necessary for the human ear to distinguish between sounds emitted by different sound sources.If the sound waves produced by different sources reach thehuman hearing aidin a time shorter than the persistence of sound, the sounds will not be interpreted as coming from different sources, but rather as if they were from a single source.Sound persistence for the human ear corresponds to 0.1 s.
echo
An echo occurs whenever the sound reflected by a certain obstacle returns to the emitter in a time equal to or greater than 0.1 s. Thus, there is a clear separation between the sound produced by the source and the sound reflected by any obstacle.
adopting thespeed of soundin air as being 340 m/s and knowing that the minimum time for the echo to occur is 0.1 s, it is possible to determine the minimum space necessary between the emitter and the obstacle for the phenomenon to occur. From the definition ofaverage speed, we can write:
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The space value must be doubled, once the sound leaves the emitter, goes to the obstacle, undergoes reflection and returns to the source. Therefore, the minimum distance for the echo to occur is:
It is observed that the minimum space required for the echo to occur is 17 m.
reverberation
Reverberation occurs when the time interval of sounds arrival in the heard human is less than 0.1 s. The perceived sensation is the prolongation of the emitted sound. Generally, when spaces such as sports halls are used for concerts or rallies, for example, there are the feeling of a repetition of words, which ends up hindering the interpretation of the messages sent. This phenomenon is a classic example of reverberation. The time between sound emission and reflection by the walls of the room is less than 0.1 s, which makes it difficult to interpret the sound waves.
Music recording studios are designed to avoid reverberation, a factor that can hinder the process of capturing both instruments and voice.
By Joab Silas
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
JUNIOR, Joab Silas da Silva. "What is echo and reverberation?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/fisica/o-que-eco-reverberacao.htm. Accessed on July 27, 2021.