CHAPTER 2 |
31
INSTALLATION AND CONFIGURATION
Acoustic Echo Canceller
Each studio has an
ACOUSTIC ECHO CANCELLER
available. The two inputs and the output are assigned to Livewire channels
on this page. The output of the AEC is labeled Backfeed because the output of the AEC is what you usually would feed back to
phones. For configuration purposes, you can think of the AEC as a separate functional block outside of other VX functions.
There is no internal connection from/to the AEC and other VX signal paths.
The Acoustic Echo Canceler helps with the problems that occur when you need to have loudspeaker monitoring of calls in the
same room as the microphone feeding the phone. Without a canceler, the received caller audio would be returned to the caller
as an annoying echo. (In the old days, this acoustic coupling would probably cause feedback howl instead of echo, but today’s
mobile phone and VoIP delays have made echo the trouble du jour. The canceler needs two inputs and produces one output. The
MIC INPUT
(From Source) is fed from the studio microphone. This can also be the entire Mix Minus signal. The
REFERENCE
(CRMON)
(From Source) input is the audio that needs to be cancelled. This is audio that is going to the monitor or preview
loudspeaker. The
OUTPUT
(To Source) of the canceler goes to the VX phone feed input(s). Lastly, the
ENABLE AEC
checkbox
does exactly what you would think it does.
Why didn’t we just internally connect the canceler? Because the canceller works best when the reference input is after anything
that is in the phone-to-speaker path, such as the volume control and mute. In a Livewire-equipped studio, it should not be too
difficult to tap the needed signals. The canceler is low-distortion and full-fidelity, so it may be used with wideband codecs.
