Which of the following correctly describes echo as it relates to acoustic echo cancellations?

The correct answer is D. The sound of the far-end being returned to themselves, caused by the room microphones picking. See the full explanation below for the reasoning.

Question

Options

AThe sound one hears when the far-end is talking and one tries to talk at the same time.
BThe sound of the room reverberation as picked up by the local microphones, amplified and
CThe result of sound bouncing off the walls in the room caused by the person speaking in that
DThe sound of the far-end being returned to themselves, caused by the room microphones picking

How the community answered

(19 responses)

A
11% (2)
B
5% (1)
C
5% (1)
D
79% (15)

Community Discussion

Orla P.Apr 24, 2026

D is your answer. Echo in the context of acoustic echo cancellation is specifically the far-end talker hearing their own voice returned to them, because the room microphones on your end pick up the loudspeaker output and send it back down the line, and AEC exists to suppress exactly that feedback loop before it leaves your site.

Bao N.May 12, 2026

D is right, it is your own voice bouncing back to the far end.

Toby R.May 2, 2026

I kept reading C and almost locked it in because "sound bouncing off walls" felt like the most textbook definition of echo I know, but then I caught that D is specifically about the far-end hearing themselves returned, which is exactly what acoustic echo cancellation is designed to fix, not just room reverb.

Viktor S.May 3, 2026

Toby nailed the distinction, though it is worth hammering home that AEC does not care about your room reverb at all, it is purely there to stop the mic from feeding the speaker signal back to the far end, so calling C even "close" on an AEC question is the kind of half-understanding that gets you killed on the real exam.

Viktor S.Apr 15, 2026

Bit C first, then remembered echo is the far-end hearing themselves.

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