How Does Echo Cancellation Work During a Video Conference?

We have all experienced our voice echoing during a video conference call. Through laptops, meeting room speakers or headphones with clients or colleagues. Even if it only occurs for a few seconds, it is extremely disruptive. It may also pause or stop the flow of a meeting until the issue is resolved. Video conferencing is becoming an increasingly essential element of business communication. It is important to understand how to cancel echo in a room. This is possible by using acoustic echo cancellation hardware or software DSP.

Why do you need an echo canceller?

An acoustic echo canceller is needed on both sides of the call during a video meeting to avoid echo. When one of the participants in the conversation begins to speak into their microphone, the signal is transmitted through a bridge, VOIP system or the Internet, which will delay the signal. This signal is then broadcast through the loudspeakers in the listener's room and picked up by their microphone. The delayed signal is then transmitted back to the original speaker's room. This is heard as the echo of their own voice. Like feedback, this is a situation that will derail a meeting.

What does echo cancellation do?

An echo canceller on the listener's side hears both the signal being picked up by the room microphones and the incoming audio that is sent to the room speakers. When it determines that the signal being sent out is the same signal that came in, it electronically cancels it so that the signal does not transmit back to the talker's loudspeakers, thus canceling the echo.

Although the echo canceller on the listener's side benefits the talker, there must be an echo canceller on both sides. This is to prevent either side from experiencing echo to have a full-duplex meeting. If you are hearing the echo of your own voice, it is actually the fault of the person on the other end of the call. They do not have a working echo canceller in their system. They are essentially allowing your voice to come back to you.

Audio Basics for IT Professionals

This topic and other essential audio basics for IT professionals are covered in this webinar. Gino Sigismondi and Chris Lyons from Shure, teach IT professionals how to navigate the blend of analog, digital, wired, and wireless technologies that combine to deliver high-quality sound for meetings and conferences. Special attention will be paid to how audio signals can co-exist with office functions on a corporate network.

Are you wondering how to cancel acoustic echo in your room? At Shure, we offer both hardware and software for acoustic echo cancellation. Our Intellimix P300 DSP offers acoustic echo cancellation as well as a lot of other features such as automix and noise reduction. Also, our software DSP, Intellimix Room, is an alternative for organizations who would prefer to have the audio DSP hosted in-room PC. 

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