Polycom EF2241 User Manual
Page 40
T
ROUBLESHOOTING
V
ORTEX
EF2241
Reference Manual
38
Technical Support: 800.932.2774
M
ATRIX
M
IXER
Don’t hear output
•
Make sure the output is not muted.
•
Check that the input you’re expecting to hear is included in the output that you’re
listening to.
E
CHO
C
ANCELLER
R
EFERENCE
Room Audio
Sounds Choppy
If you hear the local room’s audio from the loudspeakers and it sounds choppy, you
may have included the room’s microphones in the echo canceller reference. The echo
canceller reference should NOT include the local room’s microphones -- it should
only contain the remote end’s audio and program audio. You can still add the local
room’s microphones to the local output with the matrix, but do not add them to the
echo canceller reference. For more specific guidelines on what to include in your
echo canceller reference, see “Build Your Echo Canceller Reference” on page 17.
R
ESIDUAL
E
CHO
You may hear residual echo if system levels are not set properly. Improper level set-
tings anywhere in the audio path can introduce nonlinearities that hamper the opera-
tion of the EF2241. If you hear residual echo, one of the following conditions may be
causing the problem.
Reverberation vs.
Acoustic Echo
Do not confuse the residual echo of remote speech with the reverberation of local
speech. Reverberation of local speech is caused when the speech signal arrives at the
microphone via several paths (the direct path and multiple reflections from surfaces in
the room). This is a local room phenomenon that gives the talker’s voice a hollow or
resonant sound (as heard at the remote end).