Optimizing Teleconference Audio System Designs
Have you designed a large system for video or audio teleconferencing that looked straightforward and simple on paper, but turned out to be a configuration nightmare after it was wired up? Or perhaps you've even had to re-design the entire system to make it work properly? If you answered yes to either of these questions, help is on the way.
The mute function is applied after the echo cancellers. If it were applied before, the cancellers wouldn't be able to continually adapt to changes in the room. (Note: When using push-to-talk microphones, make certain their control mutes after the echo canceller and noise canceller. Otherwise, echo and noise may be heard for the first few seconds after un-muting while the cancellers are re-converging.) Filtering and AGC functions are also applied after the echo cancellers.
After processing a mic's audio for optimal echo cancellation results, the audio is finally presented to the DSP's mixer function.
Kelly Hannig is a field engineer for ClearOne Communications and provides design review support for consultants and system design engineers as well as support for on-site deployments of ClearOne conferencing products. He can be reached at Kelly.Hannig@ClearOne.com.