how do microphones in a phone not pick up any audio that the speakers put out? if I put a call on speaker mode, how do people on the other end not hear themselves?

Question

how do microphones in a phone not pick up any audio that the speakers put out? if I put a call on speaker mode, how do people on the other end not hear themselves?

In: Technology

Answer 1

The microphone is connected out of phase from the speaker, creating a phenomenon known as  phase cancellation, in which two identical but inverted waveforms summed together will “cancel the other out”