Hearing in Complex Environments

73 Indoor Spaces

Learning Objectives

Understand how echo can help us determine the layout of our environment.

Be able to define the reverberation time.

An echo is the reflection of sound from its original source. When you clap in a hallway, the clap you hear after is the echo. It works similarly to sound localization that would be used to locate a plane in the air. But instead of experiencing the direct interaction between the sound’s source and our ears, we utilize the reflection of the sound against surrounding materials and the delay this causes for the sound to reach us.

Fig. 7.5.1. Echo Chamber. An echo occurs when sound reflects off of an object from the original source. (Credit: Jarod Davis. Provided by: University of Minnesota.  License: CC-BY 4.0)

Echo also helps to determine the relative size of a space and the compositions of the materials within it. This perception is a result of reverberation time: the time it takes for a sound to decay 60 decibels from its original loudness. This is usually measured in terms of amplitude. Different materials can extend reverberation (ex. hardwood, metal) or muffle it (ex. foam, carpet) by absorbing more or less of the sound.

The sensation of echo and use of reverberation can be combined with monaural and binaural cues to create a more complex experiences of our surroundings through detailing sensory information, like hearing a myriad of musical notes in a concert that aren’t actually being played individually.


The image compares the reverb in an echoic room to a more acoustically desirable room. The echoic room has far more reverb so the noise will hang in the air much longer.
Fig 7.5.2. Reverberation time is longer in rooms with hard surfaces. The figure above shows the difference in reverberation time in two different rooms, one more prone to echo. This illustrates the difference between an echo and reverberation pretty well, essentially an echo is one reflection of sound and reverberation is many different reflections of sound. The more a room echoes the longer it will reverberate (which can also hint at the size of the room).
(Provided by: OpenStax. License: CC-BY 4.0.)




Cheryl Olman PSY 3031 Detailed Outline
Provided by: University of Minnesota
Download for free at http://vision.psych.umn.edu/users/caolman/courses/PSY3031/
License of original source: CC Attribution 4.0
Adapted by: Jarod DavisWikipedia, Echo
URL: https://en.wikipedia.org/wiki/Echo
License: CC BY SA 4.0
Adapted by: Jarod Davis

QUIZ by Kafiya Ahmed



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Introduction to Sensation and Perception Copyright © 2022 by Students of PSY 3031 and Edited by Dr. Cheryl Olman is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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