When an echo is heard in your conference, it is most often not originating with the one hearing it, but with another caller whose audio is echoing back into the conference through their phone/mic.

PREVENTING: Use the Moderator Controls:
 

• Have your calls set to Q&A mode: It is difficult to control the environment and devices used by your participants and this mode will allow you to better manage the call and resolve issues. When callers need to speak they can unmute their lines with *6 or using the mute button in the online meeting room. 
• If you notice the echo or other disturbance returns when one particular caller unmutes their line, you will know the source of the issue (see below for solutions). 
• More detailed information about how to change the mute mode of your calls and what controls are available to participants, can be found via the FAQs section of the Support Center, or type 'Moderate' in the search box above.

Common Causes:
 

• Poor quality speaker phone
• Microphone and speaker/s are very close to one another
• Multiple connections in one room
• Very sensitive microphones or input volume set too high
• Speaker volume (output) is turned up very high
• Hooked line (Calling back into the conference without properly ending the first call)
• Having a built-in mic plus an attached webcam with a mic 

Resolutions:
 

If you notice an echo or other audio issues when testing, or if you discover that echo is being introduced in the call via a participant’s line, try the following:

• Use a headset: By having the audio from a conference play directly into your ears, this completely eliminates the chance of the speaker output feeding back into your microphone.
• Move the speaker/s and microphone further away from each other: Turning external speakers outward, or pulling speakers in front of a mic can mean getting the mic out of pickup range and eliminate echo.
• Avoid multiple connections in one space: If more than one person is connected to the conference in the same room, or if you are connected to the meeting via phone as well as computer, the output audio from one line will feed back into the microphone of the other connection causing an echo. If you need to have more than one connection, ensure that you keep one line muted using *6 on a phone or the mute function in the online meeting room.
• Adjust the input and output volumes of your device/s: Reducing the mic level by a few notches can stop an echo. Similarly taking the speaker volume down can mean the speakers aren’t loud enough to feed back into the mic and so eliminate echo. 

Less common issues that can occur:
 

• Disconnect hooked lines: On rare occasions, a participant will hang up from the call, however the line will not properly disconnect and so when they call in again, a terrible echo and feedback can be heard. This can happen from time to time, particularly with landlines where the hookswitch is only briefly depressed before redialling. In this case, the best option is to use the online meeting room to disconnect any lines that you can see where someone has called in twice from the same phone number. If you are unsure who it is, then you can also end the call from within your account or as moderator, press *0 from your phone handset and have everyone call in again.
• Disable a second microphone: Some people have more than one microphone connected to their computer - this is common with an external webcam. To ensure that audio is only being received by one of those microphones you will need to disable the built in microphone on the computer. If you need help with this, just reach out to support.
• Close multiple conference room windows: It can sometimes happen that you inadvertently open a second online meeting room window in your browser without realising it. This would introduce two instances of your audio in the call, sometimes causing an echo. In this case, be sure to check all browser windows that you have open and close any duplicates.