Fm Menu Itu-R Bs.412 Processing / Mpx Power Limiting - Omnia .9 Installation & User Manual

FM MENU ITU-R BS.412 PROCESSING / MPX POWER LIMITING

CHAPTER 14 |
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FM Menu ITU-R BS.412 Processing /
MPX Power Limiting
ITU-R BS.412 requires that the average MPX power be limited to a particular standard and measured with a rolling 60-second
integration time. However, since it is impossible to know what lies ahead in terms of content, loudness must be practically
controlled within a much shorter period of time "just in case."
The factory "412" presets included with Omnia.9 are tuned in such a way that significantly less power limiting is needed to
deliver a compliant output compared to other processors. In fact, it is not at all unusual to see no gain reduction on the Power
Limiter meter at all during normal programming and only 2dB - 3dB with very bass-heavy material.
Speaking of bass, managing bass-heavy content presents a special challenge because of the amount of energy typically present
in the lower frequencies. Most of Omnia.9's "412" presets make use of the WB AGC2 or WB AGC3 compressors in "Bass Only"
mode. This allows the initial portion of the bass waveform to be managed by the clipper while the remainder is processed by
the compressor, resulting in much higher levels of bass than would otherwise be possible under the limitations imposed by the
regulations.
To prepare Omnia.9 to operate in compliance with ITU-R BS.412, MPX Power Control must first be enabled in the System >
System Config > Processing Paths menu. Be sure to "Apply Config" after enabling this mode and remember that doing so will
take the unit off-air temporarily.