ATEIS ECS - Manual (Page 49)

ECS MANUAL
Version EN.1
49
LOCAL ECHO SUPPRESSOR
The local echo suppressor is needed if a microphone is amplified and its signal is sent to a
loudspeaker for a local listening.
In this case two problems may appear. There is a risk of feedback Larsen, when the microphone
receives its own sound highly. The signal will be indefinitely amplified, which result in a high
frequency signal on the loudspeaker, very uncomfortable, called Larsen.
The second problem that may appear is the residuals echo. These echoes are due to the local
reflections.
As the sound in the room is sent to different directions, it reflects in the wall, the ceiling or the
floor. So the sound use different ways between the loudspeaker and the microphone, these ways
have different lengths that result by several little echoes.