Orban OPTIMOD 6200, Operating Manual

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OPTIMOD OPERATION
3-37
100%, they permit less and less dynamic LF and HF program-adaptive
boost. If you feel that the dynamic re-equalization is not producing enough
brightness when the program material lacks high frequencies, you should
turn the
BAND 3>4
and
BAND 4>5 COUPLING
closer to 0%. Similarly, if
weak bass is not sufficiently boosted, turn the BAND 2>1 COUPLING
closer to 0%.
J)
Set the amount of peak limiting with the
FINAL LIMT
control.
In general, the less peak limiting you use, the better sounding the result will
be. However, if your client demands a “loud” CD, the 6200’s look-ahead
peak limiter is a very powerful tool for achieving this with minimum distor-
tion or other side effects. Nevertheless, be aware that this function is not like
some familiar “look-ahead” limiters. The release time is in the order of a few
milliseconds and is not user adjustable. The purpose of the limiter is only to
limit peaks that pass through the earlier compressors because of their finite
attack times. Functionally it is used like a peak clipper, but it has vastly re-
duced modulation distortion by comparison to a clipper, whether “soft knee”
or “hard knee.”
K) Adjust the BASS CLIP control to complement the amount of final limiting.
For most mastering applications, you can set it at “0dB,” which essentially
defeats it. However, if you hear pumping or distortion in the look-ahead lim-
iter caused by heavy bass transients, you can reduce this effect by setting the
BASS CLIP to a lower level. (The BASS CLIP control is calibrated in “dB
below the final limiter threshold.”)
L) Save your preset in one of 32 user locations.
Press
ESCAPE
until you see the “home screen.” It will say “on air:
XXXXX.” The soft key to the far right will be labeled
SAVE PRESET
. Press
it and follow the on-screen instructions. (Once you have created one “mas-
tering” preset, you can edit it to create others and save them in different
locations.)
M)
For a 44.1kHz output sample rate, set the digital output level to –0.5dBfs; this will
prevent overshoots caused by sample rate conversion. For a 48kHz output sample
rate, set the digital output level to –0.1dBfs.
At 44.1kHz, the output samples are not exactly the same ones that the look-
ahead limiter controlled at the internal 48kHz sample rate, so slight over-
shoot can occur. At 48kHz output sample rate, overshoot will be less than
0.1dB.
Limitations in Mastering Applications
The 6200 was designed for the digital broadcast market (DAB, DTV, and webcasting),
and therefore has some limitations in mastering applications. The main one is lack of
individual compressor threshold controls (except on band #5) and ratio controls. The
compressors always operate with very high ratios. While this doesn’t give the usual
“squashed” sound associated with high ratios in many compressors, it nevertheless re-
moves long-term dynamic contrasts. For this reason, we suspect that most program mate-
rial will work best with 5dB or less gain reduction so that dynamic contrasts will not be
severely changed.