Reducing/eliminating echo?

Hello!

I'm trying the free version of Adobe Connect.  We are a small business and would need multi-person video call ability, which Adobe provides.  Before buying, I wanted to try the free version and did not like the echo I was getting when three people were on a video call.

I tried reducing the echo by following the flash settings.  I also got a headset with a mic to see if that helps.  While it did, there was still an echo.

Can somebody help?  Is the paid version better than the free one? How can we eliminate the echo so we can have up to 8 people on a video call, everybody getting a pretty good A/V quality?

Thanks a lot for your help, it's much appreciated!!