The exact look of the panel will vary if the device is being individually controlled or in a Master Panel. This variance also includes the controls that are included on the Master Panel.
The Limiter Block allows users to configure a limiter for the output of the amplifier to protect the speakers from damage. You have five different choices available to use:
Off
-3 dB
-6 dB
-12 dB
When Off is selected, the limiter is turned off and out of the signal path.
When -3 dB is selected, the limiter keeps the amplifier -3 dB from clip.
When -6 dB is selected, the limiter keeps the amplifier -6 dB from clip.
When -12 dB is selected, the limiter keeps the amplifier -12 dB from clip.
If you are connected to the Internet you can find additional information, including video overviews at:
http://www.crownaudio.com/tutorials/