Surround : Surround Panning and Mixing : LFE Faders in Multichannel Panners : LFE Enable

LFE Enable
Some multichannel plug-ins, including the multichannel Dynamics III Compressor/Limiter, provide LFE Enable. This lets you enable or bypass processing of the LFE channel if present.
 
To process the LFE channel in a multichannel plug-in:
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Click to enable LFE Enable in supporting multichannel plug-ins. LFE Enable is highlighted when LFE processing is enabled, and unhighlighted when LFE processing is bypassed.
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When LFE Enable is unavailable, try using the multi-mono version of the plug-in.