Noise Reduction - Shure MXA920 Manual

When possible, optimize the acoustic environment using the following tips:
• Reduce loudspeaker volume
• Position loudspeakers farther from microphones
• Avoid pointing loudspeakers directly at microphone coverage areas
• If the microphone is providing AEC from the automix output, turn off AEC on the processor. Designer's auto route applies
these settings automatically.
Select a Reference Signal for AEC
To apply AEC, provide a far end reference signal. For best results, use the signal that also feeds your local reinforcement sys­
tem.
• P300: Go to Schematic and click any AEC block. Choose the reference source, and the reference source changes for all
AEC blocks.
• MXA710, MXA901, MXA910, MXA920: Route a far-end signal to the AEC Reference In channel.
• IntelliMix Room: Go to Schematic and click an AEC block. Choose the reference source. Each block can use a different
reference source, so set the reference for each AEC block. When stereo audio is on, you can set different left and right
channel reference sources as needed.
Designer's auto route process automatically routes an AEC reference source. However, you should check that Designer choos­
es the reference source you want to use.
Note: Always send an AEC reference signal to microphones with AEC processing, even if you are using a separate DSP for AEC. Designer's auto route fea­
ture automatically creates these routes.
AEC Settings
Reference Meter
ERLE
Reference
Non-Linear Processing

Noise Reduction

Noise reduction significantly reduces the amount of background noise in your signal caused by projectors, HVAC systems, or
other environmental sources. It is a dynamic processor, which calculates the noise floor in the room and removes noise
throughout the entire spectrum with maximum transparency.
Use the reference meter to visually verify the reference signal is present. The reference sig­
nal should not be clipping.
Echo return loss enhancement (ERLE) displays the dB level of signal reduction (the amount
of echo being removed). If the reference source is connected properly, the ERLE meter ac­
tivity generally corresponds to the reference meter.
Indicates which channel is serving as the far end reference signal.
The primary component of the acoustic echo canceller is an adaptive filter. Non­linear pro­
cessing supplements the adaptive filter to remove any residual echo caused by acoustic ir­
regularities or changes in the environment. Use the lowest possible setting that is effective in
your room.
Low: Use in rooms with controlled acoustics and minimal echoes. This setting provides the
most natural sound for full duplex.
Medium: Use in typical rooms as a starting point. If you hear echo artifacts, try using the
high setting.
High: Use to provide the strongest echo reduction in rooms with bad acoustics, or in situa­
tions where the echo path frequently changes.
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