Orban OPTIMOD 8400 - HD Audio Controls

OPTIMOD-FM INSTALLATION
2-65
HD Audio Controls
Included with each preset in Advanced Control.
Function Control Name Values
HF Shelving Filter
HD Eq Gain 0…–6 dB; 0.5 dB steps
HD Eq Freq 2…– 20 kHz; 1/6-octave steps
Look-Ahead Limiter
HD Limiter Drive 0…+12 dB; 1.0 dB steps
HD Eq Gain
determines the depth of high frequency shelving equalization produced by
the parametric HF shelving equalizer, which will be placed either before or after the digi-
tal-channel look-ahead limiter (depending on the setting of the
HD HF EQ control in the
I/O Setup section).
When placed before the look-ahead limiter, this equalizer is useful for reduc-
ing the audible disparity between the FM and digital-channel outputs. The
digital-channel output receives no high frequency limiting or clipping and
may therefore be as much as 6 dB brighter than the FM output. If you wish
to reduce this difference to smooth out the audible difference between the
two channels during a receiver crossfade, you can apply HF rolloff to the
digital-channel channel by ear. Another reason you might want to do this is
if the digital-channel channel sounds excessively bright after you have opti-
mized the 8400’s tuning for FM.
Yet another reason to use HF rolloff in the digital-channel channel is to re-
duce codec artifacts at the high frequencies—the familiar “watery” sound.
When placed after the look-ahead limiter, the shelving EQ can reduce the ef-
fects of codec overshoot.
The parametric HF shelving equalizer can only produce HF rolloff. It cannot
boost.
HD Eq Freq sets the corner frequency of the parametric HF shelving equalizer.
HD Limiter Dr
sets the drive level to the digital-channel look-ahead limiter.
This control is located in the Clippers screen (Advanced screen 7) in Ad-
vanced Control
.
The factory default is +4.
Because its loudness must match the FM channel, there is no need to over-
process the digital channel. HD “loudness wars” will not only reduce quality
but will also cause unbalanced, obtrusive crossfades between the analog and
digital channels in the radio. To brand your station’s sound, you can choose
the precise coloration you want on the digital channel. You can still take ad-
vantage of all of the artistic choices implicit in stereo enhancer, equalization,
and multiband compression/limiting settings. Yet you do not need to use ex-
cessive peak limiting, which can only reduce quality.