Science · 6 pages · 12 min

How an echo finds a wall

The sound bounces off a hard surface and comes back after a delay.

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From the opening

An echo is a sound that has bounced off a surface and come back to you later. The delay is the travel time out and back, so a farther wall answers later. The opening covers a pressure wave that reflects, why the delay measures distance, and echo versus room reverberation.

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Inside

A pressure wave that reflects
Why the delay measures distance
Echo versus room reverberation
Why soft surfaces stay quiet
Where the idea stops applying
A distinction worth keeping

Sources

Reflection of sound waves from a hard surface
Round-trip delay as a measure of distance

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How an echo finds a wall

From the opening

Inside

Sources

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