I am primarily an Audio systems designer. We are working on a training facility that will use Webex to perform distance learning. This system will be comprised of a PC, large screen (80") display and an audio system for a room of 50 attendees. The facility moderator has a microphone to communicate with the Webinar and with the attendees through the audio system. Does any one have experience with this type of setup and what equipment is necessary to mitigate any echo.