MediaPort 200 • Theory of Operation
8
Speakerphones and AEC (Acoustic Echo Cancellation)
When a microphone or microphone mix is connected to the MediaPort and the MediaPort
is connected to a sound system to amplify audio from the far end of the conference, the
MediaPort functions in the same way as a speakerphone. In a conference call, when
the far end talker is amplified in the local room, that signal can be picked up by the local
microphones and sent back to the far end. That audio is delayed and then heard by the far
end talker as an echo of their voice.
This echo is often referred to as “acoustic echo” because it travels through the acoustic
space from the sound system to the microphones. A specific type of processing, called
“acoustic echo cancellation,” or AEC, is used to cancel the echo signal and prevent it from
being sent back to the far end.
Standalone Mode
In the Standalone audio mode, the computer recognizes the MediaPort as a
Speakerphone
. In this mode,
Speakerphone
–
MediaPort
200
is chosen as the audio
device in a soft conferencing application such as Skype for Business and in Windows. When
a speakerphone is the selected audio device, the host conferencing application uses its
built-in AEC to cancel the acoustic echo.
External DSP with AEC Mode
In the External DSP with AEC audio mode, the computer recognizes the MediaPort as
an
Echo Cancelling Speakerphone
. In this mode,
Echo
Cancelling
Speakerphone
–
MediaPort
200
is chosen as the audio device in a soft conferencing application such
as Skype for Business and in Windows. When an echo cancelling speakerphone is
the selected audio device, the soft conferencing application AEC should be turned off
automatically. In this case, an external DSP is connected to the MediaPort Mic/Line input
with the AEC applied in the external DSP processor.
