How to avoid echoes in a phone conference using Zoom or GotoMeeting

If you've used web conference system such as Zoom or GotoMeeting or similar, you probably have encountered the problem of echoes. Here's three guidelines for a good audio conference:

1. Mute yourself when not speaking.

Train everybody to mute themselves when they're not speaking; this is The Golden Rule for good audio conferences.

2. Use the phone rather than computer for audio.

The phone is built for audio; it's simple and reliable; by contrast, computers and their TCP/IP networks are not designed for voice. Their microphones are near the keyboard and fan, from which they pick up unwanted noise; their speakers are acoustically very close to their microphones; TCP/IP is not designed to carry voice even though we have many VOIP systems. The phone just wins, hands down.
Only use your PC for screen-sharing, not sound.
Only use the computer for voice if you really have to.

3. Only use ONE audio device per room.

Do not have two PC's running audio, or two phones on speaker, in the same room, or you will most likely get bad echoes.

For more in-depth technical solutions to audio and video conferencing, see this article.