Orban OPTIMOD-FM 8500S Operating Manual page 224

3-60
OPERATION
overload, but unlike the MB B
quency response when a given band is below threshold and is thus pro-
ducing no gain reduction.
On/Mute switches allow you to listen to any band (or any combination of bands) in-
dependently. This is a feature designed for intermediate or advanced users and de-
velopers when they are creating new 8500S presets. The mute control for a given
band affects both the FM and HD processing because it mutes the input of compres-
sor in that band. This prevents the muted compressor's sidechain from producing a
gain reduction signal that could couple into unmuted bands through the various
band-coupling controls.
Please note that a single band will interact with the back-end clipping system quite
differently than will that band when combined with all of the other bands. There-
fore, do not assume that you can tune each band independently and have it sound
the same when the clipping system is processing all bands simultaneously.
Compression Threshold; Speech Compression Threshold controls set the com-
pression threshold for music and speech in each band (following the 8500S's auto-
matic speech/music discriminator), in units of dB below the final clipper threshold.
We recommend making small changes around the factory settings to avoid changing
the range over which the MB C
the spectral balance of the processing above threshold, but are also risky because
they can significantly affect the amount of distortion produced by the back-end
clipping system.
You can use these controls to set independent frequency balances for music and
speech (page 3-63).
B1-B4 Attack (Time); Speech B1-B4 Attack controls set the speed with which the
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 8500S'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 3-63), you can set
attack times faster for speech (to minimize clipping distortion) and slower for music
(to maximize punch and transient definition).
The A time controls are calibrated in arbitrary units that very approximately
TTACK
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 A
time setting.
controls, does not affect the fre-
M
AND IX
control operates. These controls will affect
LIPPING
time controls to minimize overshoot for any attack
TTACK
ORBAN MODEL 8500S