Record a remote interview without headphones and you’ll find out what a feedback loop is almost immediately. Your guest’s voice plays through your speakers, your microphone picks it up, sends it back to them, their microphone picks up the delayed version from their speakers, sends it back to you, and within seconds you’ve got an escalating echo that makes the conversation impossible. If you’ve never heard this happen, that’s because echo cancellation is on by default in your recording software. This is the problem echo cancellation was designed to solve, and in this situation it does help. But it comes with tradeoffs.

How it works

Echo cancellation works by analyzing the audio going to your speakers and removing it from your microphone input in real time. When it works well, it’s invisible. Your guest talks, you hear them through your speakers, but your microphone only picks up your voice. The algorithm constantly adjusts, trying to predict and remove the echo before it loops back. In practice, it never works quite that cleanly.

Tradeoffs

Echo cancellation introduces artifacts. You’ll hear strange warbling when multiple people talk at once, because the algorithm gets confused about what to cancel. Certain frequencies get muddy or disappear entirely. There’s often a subtle but noticeable pumping or breathing effect as the algorithm adjusts to changing audio levels. It also struggles to tell plosives and other consonants apart from echo, so they come out smeared and lose their crispness.

Interviews with lots of crosstalk are the real nightmare. Each echo cancellation algorithm handles it in its own way, but none of them eliminate the artifacts completely.

Some recording platforms and video conferencing tools also bundle echo cancellation with other automatic processing, like noise reduction, reverb removal, and compression. Often you can’t turn these off individually, so you’re stuck with whatever the algorithm decides your audio should sound like.

So what should you do?

I won’t say everyone must use headphones, because for many reasons that’s almost impossible. So use echo cancellation, but only when you need it. If neither of you has headphones, turn it on at both ends. Anyone wearing headphones should turn it off.