Orban OPTIMOD-FM 8600Si Operating Manual Download Page 234

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3-68

OPERATION

ORBAN MODEL 8600Si

gain reduction in each band responds to level changes at the input to a given band’s
compressor for music and speech respectively, following the 8600Si’s automatic
speech/music detector. These controls are risky and difficult to adjust appropriately.
They affect the sound of the processor in many subtle ways. The main trade-off is
“punch” (achieved with slower attack times) versus distortion and/or pumping pro-
duced in the clipping system (because slower attack times increase overshoots that
must be eliminated in the clipping system). The results are strongly program-
dependent and must be verified with listening tests to a wide variety of program
material.

Because there are separate controls for music and speech (page 3-70), you can set
attack times faster for speech (to minimize clipping distortion) and slower for music
(to maximize punch and transient definition).

The

TTACK

time controls are calibrated in arbitrary units that very approximately

correspond to milliseconds. Higher numbers correspond to slower attacks.

The look-ahead delay times in bands 3, 4, and 5 automatically track the
setting of the

TTACK

time controls to minimize overshoot for any attack

time setting.

Only the five-band MX presets have Band 5

TTACK

controls for the FM

analog processing. In the 8500-style presets, the band 4 and band 5 com-
pressors share one compression sidechain, although their associated clip-
pers and downward expanders operate independently.

MB Limit Thr

(available in 8500-style presets only) sets the threshold of the clipping

distortion controller with reference to the threshold of the final clipper, in dB.

For best clipping distortion control, most effective setting for this control
is “0 dB” for almost all program material. However, the loudest and most
intense-sounding 8500-style presets rely on considerable clipping to
achieve their loudness and brightness. For these presets, we found it nec-
essary to set the

IMIT

control substantially higher than “0” to

permit more clipping depth. In some cases, this results in substantially ob-
jectionable distortion artifacts with isolated program material. However,
this is the price to be paid for this extreme level of on-air loudness.

For the

NEWS-TALK

and

SPORTS

presets, we set the

IMIT

con-

trol slightly below “0.” This ensures the cleanest possible speech quality
at the cost of highest loudness. If you want higher loudness in these pre-
sets, you can edit them to increase the setting of the

IMIT

con-

trol.

If you set this control too low, (and/or set the

LIPPING

control too

high) the first artifact that you are likely to notice is intermodulation dis-
tortion between vocals and bass. Be aware of this possibility when you
are adjusting this control, because the effect sometimes becomes clearer
once you are accustomed to listening for it. Headphone listening will
usually increase the audibility of this artifact.

This control does not affect the HD processing chain.

Max Dist Ctrl;

Speech Max Dist Ctrl

(available in 8500-style presets only) limit the

maximum amount of final clipper drive reduction (in dB) that the 8600Si’s clipping
distortion controller can apply in Music and Speech modes respectively, preventing