The echo is a repetition of the sound that arrives at the listener. If you hear audio echo or audio feedback during your meeting, then this might be caused by:

1. Multiple devices with active audio in the same room;

2. Not using a headset;

Multiple devices with active audio in the same room

If you are in a room where multiple devices connected to the same meeting have their microphone enabled, then some microphones might channel your audio back, hearing it as an echo in the meeting. 

To avoid this, if you encounter yourself in such a situation, make sure that you are not close to the other participants, or one of you has the microphone on mute, while the other one is speaking. 

Not using a headset

When not using a headset, and relying on your PC speakers and microphone, changing the sound settings on your computer can help minimize echo issues. Try the following before that:

• Lower your speaker volume to reduce the echo;
• If your microphone or audio device is near a wall or other reflective surface that does not absorb sound, consider moving the microphone or changing its direction away from the reflective surface to reduce potential echoes;
• If you’re using your webcam’s microphone or your computer speakers, try using a different audio device such as a headset, handset, or standard microphone;
• If possible, try placing the microphone as far away as possible from the computer speakers because the audio output from the speakers may feed into the microphone and produce echoes.
• If you are using a laptop with an integrated sound card that supports Microphone Boost (Noise Suppression/Ambient Noise reduction), disabling Microphone Boost can help you isolate the issue: 

On Windows 

• Click Start, and then click Control Panel.

• In Control Panel, click Hardware and Sound, and then click Sound.

• In the Sound dialog box, on the Recording tab, select your microphone, and then click Properties.

• In the Microphone Properties dialog box, on the Levels tab, uncheck the Microphone Boost (Noise Suppression/Ambient Noise reduction)checkbox (if available);

On Mac

• In System Preferences in your Launchpad, click on the Sound icon;
• In the Input tab select the microphone that you are using;
• Uncheck the Ambient Noise reduction checkbox;

Other Tips:

Generally, if you are hearing echo, it means that there is a device out there that is channeling your audio back.

To isolate the attendee:  

• The host can mute the attendees one at a time;
• The attendee can mute him/herself;

The source of echo can also be from: 

• Speakers that are too loud;
• Echo cancellation has failed (device or performance issue);
• A bad microphone;