Operating instructions

OPTIMOD-AM DIGITAL OPERATION
3-53
duction in band 5. Higher settings produce more HF limiting. A setting of “–18” pro-
vides a good trade-off between brightness and distortion at high frequencies.
Limiter Attack
controls allow you to set the limiter attack anywhere from 0 to
100% of normal in the Five-Band compressor / limiters. Because the limiter and com-
pressor characteristics interact, you will usually get best audible results when you set
these controls in the range of 70% to 100%. Below 70%, you will usually hear
pumping because the compressor function is trying to generate some of the gain
reduction that the faster limiting function would have otherwise produced. If you
hear pumping in a band and you still wish to adjust the limiter attack to a low set-
ting, you can sometimes ameliorate or eliminate the pumping by slowing down the
compressor attack time in that band.
Delta Release
controls are differential controls. They allow you to vary the release
time in any band of the Five-Band compressor/limiter by setting an offset between
the M
ULTIBAND RELEASE setting and the actual release time you achieve in a given
band. For example, if you set the M
ULTIBAND RELEASE control to medium-fast and the
B
AND 3 DELTA GR control to –2, then the band 3 release time will be the same as if
you had set the M
ULTIBAND RELEASE control to medium and set the BAND 3 DELTA GR
control to 0. Thus, your settings automatically track any changes you make in the
M
ULTIBAND RELEASE control. In our example, the release time in band 3 will always be
two “click stops” slower than the setting of the M
ULTIBAND RELEASE control.
If your setting of a given D
ELTA RELEASE control would otherwise create a release
slower than “slow” or faster than “fast” (the two end-stops of the M
ULTIBAND
RELEASE control), the band in question will instead set its release time at the appro-
priate end-stop.
This control is particularly useful in B5, allowing B5 to function as a fast de-esser
while the other bands use slower release times.
Band 1-5 MaxDeltGR
See page 3-59.
B1/B2 Xover
(Band 1 to Band 2 Crossover Frequency) sets the crossover frequency
between bands 1 and 2 to either 100 Hz or 200 Hz. It affects the bass texture signifi-
cantly, and the best way to understand the differences between the two crossover
frequencies is to listen.
Lookahead
activates or defeats the look-ahead functionality in the AM multiband
compressor/limiter. Defeating look-ahead improves transient impact at the expense
of distortion, particularly on speech. To mitigate this tradeoff, a selectable “auto”
mode turns look-ahead on for speech material and off for music, using an automatic
speech/music detector. Switching is seamless and click-free because we change the
delay in the compressor control sidechains; this is not a way to reduce the 9400’s
throughput delay.
Choices are L
OOKAHEAD IN, OUT, and AUTO.
Speech is detected if (1) the input is mono, and (2) there are syllabic
pauses at least once every 1.5 seconds. Speech with a stereo music back-
ground will usually be detected as “music,” or the detector may switch