Question

What is echo ? What is the minimum distance to hear echo?

Answer 1

Echo....... In audio single processing and acoustics, echo is reflection of sound that arrives at the listener with a delay after the direct sound....
The delay is proportional to the distance of the reflecting from the source the listener...

Answer 2

echo is repeatation of sound from medium to another means like light rays reflect from one medium to another same like echo .the sound waves reflect from one to another medium but in a open space,ex: mountain areas,an empty house.i f like my answer then Mark as brainleist. thank you