What's the science behind audio echo on conference calls?

Question

We've all been on Zoom (or conference call app of your choice) where, due to people being in close proximity, or other reasons, there is harsh audio echo/feedback.What is the science behind this? Why does that occur? We all understand what to do when such echo occurs ("can someone please mute?" "can someone turn off their volume?"), but what actually drives this phenomenon?

PaulHoule · Accepted Answer

It's like any other kind of echohttps://en.wikipedia.org/wiki/EchoThe sound comes out of the speaker. Some goes straight into the microphone, some of it bounces off the walls, the floor, your body, etc. and gets picked up by the microphone. Thushttps://en.wikipedia.org/wiki/Echo_suppression_and_cancellat...is necessary.