Cisco D9887B Installation And Configuration Manual page 267

Audio Setup
"Custom 0" disregards the Dolby dialog normalization data and runs at a fixed gain.
Choosing "RF" as the compression mode will increase the gain by 11 dB for the
analog outputs, AES digital outputs set to PCM, and any embedded outputs set to
PCM.
If you want to run with no processing, set "User / Custom 1 / L/R / Dynamic
Range" to disabled. This will still allow gain changes called for in the Dolby
metadata.
78-4043743-01 Rev A 243