Why is an echo weaker than the original sound?

Question

Physics topic

Answer 1

The echo is a reflection of the pressure waves caused by the sound. As such, the waves have lost energy as they pass bump into the trillions of tiny molecules on their way to the wall and on their way back. The loss of energy means the amplitude of the wave is reduced, and the strength of the vibrations in your ear is diminished accordingly.

Answer 2

Energy in sound waves dissipates with distance. With no obstructions the energy level will follow the inverse square law. An echo is sound reflected from some surface or combination of surfaces, usually some distance away (at least 500 ft for a clearly discernible discreet echo). With some reflective shapes, there is very little attenuation of energy, and the echo is nearly as loud as the original sound. In certain special circumstances constructive interference can produce an ever-increasing volume of sound until the source is quieted..

Answer 3

An echo is a signal that has been propagated through the air from
some object whose surface created a reflection of the signal. Whenever a
signal propagates in space, it spreads out with some of the signal going off
in different directions away from the original direction. The signal left on
the original beam is less than the whole beam that started so the energy in
the received beam is always less. For a point source the energy per unit area
drops off as the inverse square of the distance.

Answer 4

'Cause the sound wave loses energy across the distance from its origination to its bounce point, also the surface may absorb sound energy, as well as the return trip loss from it's reflection back to the receiver/ear.
Note the transmission mediums, ie. water, air, etc. also have individual specific characteristics that influence sound attenuation.
An echo can't effectively return the original strength because sound seldom bounces straight and not all of the wave form will be reflected back uncorrupted.

Answer 5

An echo is sound bouncing back to you.

When it bounces back, it dissipates and it doesn't all come back to your ear. It goes in many directions.