Processing Parameters
20
'ATTACK'
Controls the attack rate of the AGC, The time the AGC takes to respond to an increase of
input level. The attack time can be varied between 1 and 10 which corresponds to 100mS to 30S on
a semi-exponential scale.
'DECAY'
Controls the release/decay rate of the AGC, the time the AGC takes to respond to a
decrease of input level. The DECAY time can be varied between 1 and 10 which corresponds to
100mS to 30S on a semi-exponential scale.
'GATE THRESHOLD'
The gate function prevents 'suck-up' of noise during periods of silence or low
level audio. The level can be adjusted to turn on when the input drops to a level from -20dB to -40dB.
The gate can also be switched off or forced on. The gate when turned on will cause the gain reduc-
tion to move towards the level set by the RTR LEVEL control and to move towards that level at the
rate set by the RTR speed control.
'RTR LEVEL'
The return to rest level sets where the gain reduction will move towards under GATED
conditions. The RTR LEVEL can be set to -4dB, -8dB, -12dB, -16dB or -20dB. There is also an AUTO
setting which continuously modifies the RTR LEVEL based upon a rolling average of the last 30 sec-
onds of gain reduction prior to the GATED condition occurring.
'RTR SPEED
' The return to rest speed modifies the attack and decay rates under gated conditions.
The rate can be slowed down by factors of 1, 2, 4, 8, 16 and 32. This control can leave the rate
unmodified (setting of 1) or slow it down to the point of being frozen (32)
'WINDOW GATING'
A separate gating control from the silence gate, the window gate slows down
the attack and decay rates when the audio waveforms level has not moved outside of a pre-defined
window, set by the window gating control. The window can be set between 1 and 6dB or the gate
function can be disabled by setting the control to OFF. The window gating prevents unnecessary gain
control when the audio waveform is already well defined or having a low peak to average ratio. The
window gating also allows faster rates to be used without the audible effects normally associated with
the faster rates.
The multi-band AGC bands can be individually disabled by setting the RTR LEVEL to a fixed level,
usually -12dB and setting the 'GATE THRESHOLD' to ON. This creates unity gain through the AGC
when the bands drive control is set to 0 dB. The multi-band AGC can be used as a linear phase EQ
stage whose curve is set by the RTR LEVEL controls
'GATING TYPE
' This control allows the user to select whether each of the multi-band AGC’s silence
gates work individually or on a ‘one gates all’ basis. Make sure you know what you are doing before
selecting the combined ‘one gates all’ option as it can cause strange effects to occur if the individual
bands gating thresholds are not set appropriately. You would normally turn off the B1 and B4 gates if
selecting this option to avoid gating in the absence of bass or high frequencies. If in doubt ask BW or
leave this control set to the individual option
'B1<2 COUPLING
' This coupling control determines the percentage of B2’s gain control path that is fed
to B1’s gain control path.
'B3<2 COUPLING
' This coupling control determines the percentage of B2’s gain control path that is fed
to B3’s gain control path.
'B2<3 COUPLING
' This coupling control determines the percentage of B3’s gain control path that is fed
to B2’s gain control path.
'B4<3 COUPLING
' This coupling control determines the percentage of B3’s gain control path that is fed
to B4’s gain control path.
The band coupling controls can restrict the ability of the bands to wander excessively, destroying the
original spectral balance of the input program material. Lower couplings allow more re-equalisation to be
performed for a more consistent tonal balance. 30% is a good compromise.
'L/R COUPLING
' This coupling control determines the percentage that the left and right channels are
linked. 0% is completely uncoupled and equates to a dual mono processing architecture. 100% coupling
ensures the stereo balance of the input program material is maintained. Less coupling can widen the
stereo image for a ‘FAT’ sound.
