User manual

MRD 3187B User Manual
Page 125
button to save the selection.
MRD 3187B Audio Explanation
Audio Setup
There are three primary modes of audio down mix operation for the 8733 decoder. These
settings only affect the signal if the digital output is set to “PCM.” It will also affect those
embedded audio channels that are set to a PCM Downmix as well as analog audio.
Note: There are no gain changes if the digital or embedded outputs are set to Raw.
The modes are “Monitor” (the default setting), “Transmission”, and “User.”
The first mode is “Transmission.” It allows no changes by the customer. It is intended to
provide a limited dynamic range signal to drive a set top box or a transmitter. The
“Transmission” mode does respond to dialog normalization data. It provides a gain boost of
11 dB and has compression to prevent the signal from overdriving a modulator. The 11dB
gain boost is applied to the analog outputs, AES digital outputs set to PCM, and any
embedded outputs set to PCM.
Note: It will not affect the gain of digital outputs or embedded outputs set to Raw.
It is intended to provide a similar audio level as a broadcast TV station signal through an RF
modulator. The down mix includes the “center” and “surround” channels if they are present,
and is represented as Lt/Rt. (left total/right total)
The second mode is “Monitor.” It has moderate processing, no gain boost and its down mix
involves left and right channels only (L/R). The compression setting is “Line” mode as the
default, but may be changed to “RF”, “Custom 0” or “Custom 1.” In “Line” mode, the Dolby
dialog normalization data is followed. No other parameters may set by the customer. It is
intended for monitoring of sources with only some peak limiting protection. Selecting “RF”
as the compression setting will add 11 dB of gain and the same processing as the
“Transmission” mode to the analog outputs, AES digital outputs set to PCM, and any
embedded outputs set to PCM. The down mix is L/R (left only/right only)
The third mode available is “User.” It allows all parameters to be set by the operator. The
compression choices are “RF”, “Line Mode”, “Custom 0”, and “Custom 1.” RF and “Line
Mode” essentially duplicate the first two modes of audio down mix described above. The
“Custom 0” and “Custom 1” modes have no audio processing or gain boost. “Custom 1”
does enable gain changes called for by the dialog normalization data. It allows the operator
to enable or disable the dynamic range (peak limiting) and select the channels to down mix
“Lt/Rt”, “L/R”, “Mono L”, and “Mono R”. Mono left or Mono right applies that signal to
both left and right channels of the digital service, left and right channels of the analog
outputs, and left and right channels of any embedded stream set to PCM. “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 11dB 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, then set “User / Custom 1 / L/R / Disabled.” This will
still allow gain changes called for in the Dolby metadata.
Audio Output Settings
The digital audio services may be set to “PCM” (AES) or “Raw” as an output. This applies
to all available sources. The “PCM” setting will pass an AES stream, or automatically down