Gain Structure - Extron electronics MediaPort 200 User Manual

Gain Structure

Proper gain structure is essential to achieving optimal performance from the MediaPort 200
and related equipment. Refer to the Extron white paper,
Systems, for detailed information.
NOTE: To view the white paper, an Extron Insider account is required.
MediaPort 200
Extron Product Configuration Software (PCS) provides a tabbed interface for setting audio
gain and mixing audio levels within the MediaPort 200.
Input tab
Setting proper input gain is fundamental to any audio device, and therefore, the Input
tab is placed first in the Audio Config section of PCS. The MediaPort 200 uses digital
peak meters, referenced to 0 dBFS, or "full scale." The strongest level that can be achieved
without clipping is the optimal signal level, in other words, approaching 0 dBFS yet with
sufficient headroom to never reach 0 dBFS, which is clipping. Clipping a digital audio device
produces immediately audible and undesirable distortion.
In order to achieve this optimal level without clipping, a strong yet safe target signal level
must be established. To derive a dBu equivalent on the MediaPort peak meter referenced to
0 dBFS, the MediaPort max input level of +21 dBu must be considered. Subtracting
17 dB from +21 dBu gives us +4 dBu. Therefore, −17 dBFS on the MediaPort input meters
is the approximate equivalent to +4 dBu.
With −17 dBFS as a target, the average audio signal will be −17 dBFS while varying
approximately ±10 dB above or below that level. That would put the strongest, or "hottest"
signal at about −6 to −8 dBFS. This is a safe level for program or microphone signals.
Mix tab
When input gain is properly set, all listening levels can be set and run‑time operation can
then be performed from the mix tab. Line Inputs and USB Communications levels have a
range of −100 to +12 dB, but it is recommended to avoid going above 0 dB as this may
cause clipping. There may be cases where the extra gain is needed. The Mix tab contains
a Room Volume control, which may be the only control that needs adjustment once other
controls are properly set. See section, Using the Mix Tab
MediaPort 200 Audio Application Tutorial • Gain Structure
Audio Gain Structure for Pro AV
on page 10 in the user guide.
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