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3-50
OPERATION
ORBAN MODEL 1101
Obviously, the correct setting will be different for a sporting event than for classical
music. It may be wise to define several presets with different settings of the MB
control and to recall the preset that complements the program ma-
D
E
OWN
XPANDER
terial of the moment.
Note also that it is virtually impossible to achieve undetectable dynamic noise reduc-
tion of program material that is extremely noisy to begin with, because the program
never masks the noise. It is probably wiser to defeat the dynamic noise reduction
with this sort of material (traffic reports from helicopters and the like) to avoid ob-
jectionable side effects. You must let your ears guide you.
Band 5 is particularly critical for noise reduction because much of the Downward
Expander's utility lies in hiss reduction. Hiss has most of its energy in band 5, while
program material typically has less energy in this band, so the B5 D
E
OWN
XPANDER
control's setting is critical to removing hiss while minimizing removal of desired pro-
gram energy.
Starting in V2.1, the Downward Expander's dynamic frequency response is no longer
constrained to being strictly lowpass—Band 5 is now uncoupled from the lower
bands, so the band 5 downward expander can produce less gain reduction than
other bands. This can help prevent loss of desired high frequency material in the
program. Moreover, the lowest threshold setting has been lowered from –6 to –18
dB. This allows the Downward Expander to operate more subtly on material that is
only moderately noisy, like many old music recordings.
B3>B4 CPL ("Band 3>4 Coupling") control determines the extent to which the gain
of band 4 (centered at 3.7 kHz) and 5 (above 6.2 kHz) are determined by and follows
the gain of band 3 (centered at 1 kHz). Set towards 100% (fully coupled) this control
reduces the amount of dynamic upper midrange boost, preventing unnatural upper
midrange boost. The gain of band 5 is further affected by the B4>B5 CPL control.
Excessive HF energy is one cause of audibly objectionable artifacts in low bitrate co-
decs. The B3>B4 C
B4>B5 C
controls can be very useful in reducing such arti-
PL AND
PL
facts—setting them for large amounts of coupling will minimize OPTIMOD-PC's abil-
ity to dynamically increase high frequency energy.
B4>B5 CPL ("Band 4>5 Coupling") controls the extent to which the gain of band 5
(6.2 kHz and above) is determined by and follows the gain of band 4.
The sum of the high frequency limiter control signal and the output of the B4>B5
CPL
determines the gain reduction in band 5. The B4>B5 CPL control re-
CONTROL
ceives the independent left and right band 4 gain control signal. Range is 0 to 100%
coupling.
B3>B2 CPL and B2>B3 CPL controls determine the extent to which the gains of
bands 2 and 3 track each other.
When combined with the other coupling controls, these controls can adjust the five-
band processing to be anything from fully independent operation to quasi-
wideband processing.
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