Rane DC 24 Users Guide [RaneNote 130] - Manual (Page 4)

DC 24 Users Guide-4
VISUALIZING ALL THIS
Figure 1 shows a couple of different configurations,
depending on the positions of the Crossover / Dual / Combine
switches that truly make the DC 24 a multi-function unit. It
can be a two way crossover, with independent processing on
the low and high outputs. The outputs can be summed with
the Separate/Combine switch, and the Crossover can be
switched in (see rear panel above), so that processing the low
and highs separately can take place in a mono or send/return
application. Even though the outputs are summed at Channel
Compressed
Output Range
No Processing
Output Range
Expanded
Output
Range
Input Range
to Expand
No Processing
Input Range
Input Range
to Compress
-70 -60 -50 -40 -30 -20 -10 0 +10 +20 +30
-80
-70
-60
-50
-40
-30
-20
-10
0
+10
+20
+30
R
at
io
1
:1
O
utp
ut Le
ve
l =
In
pu
t L
eve
l
Expander Threshold
All signal decreases less than this setting
are made bigger by the ratio amount.
Expander Ratio
Determines this slope. The output change
is more than the input change by the
ratio amount. For example, a 5 dB input
decrease produces a 10 dB output
decrease for a 2:1 ratio setting.
Compressor Threshold
All signal increases greater
than this setting are made
smaller by the ratio amount.
Compressor Ratio
Determines this slope. The output
change is less than the input change
by the ratio amount. For example, a
10 dB input increase produces only a
5 dB output increase for a 2:1 ratio setting.
Limiter Ratio
At least 10:1, meaning a
10 dB increase in input level
results in no more than a 1 dB
increase in output level.
Limiter Threshold
All input signal changes greater
than this setting, produce no
significant output increase.
Output Signal Level dBu
Input Signal Level dBu
Gate Threshold
All signal changes
less than this setting
essentially produce
zero output, i.e., the
output is muted.
2-WAY CROSSOVER MODE COMBINE MODE
CHANNEL 1
INPUT
CROSSOVER CROSSOVER
CH. 1
CH. 2
CH. 1
CH. 1
CH. 2
CH. 2
LOW OUT
LOW OUT
COMBINED OUT
HIGH OUT
SUM
OUTPUTS CH 2 TRIM
CH 2 HIGH /
COMBINE OUT CH 2
IN
CROSSOVER
ENGAGE CLASS 2 EQUIPMENT
CH 1 /
CROSSOVER IN
CH 1 /
LOW OUT
DC 24
+4 dBu COMBINE SEPARATE -10 dBV
TIP=SEND
RING=RETURN TIP=SEND
RING=RETURN
INPUTS AND OUTPUTS
TIP=#2=POSITIVE
RING=#3=NEGATIVE
SLEEVE=#1=SIGNAL GROUND
CH 1
SIDE CHAIN
CH 2
SIDE CHAIN
MADE IN U.S.A.
RANE CORP.
N108
+4 dBu -10 dBV
CH 1 TRIM
600mA
POWER
Front Panel DUAL / SLAVE switch
Figure 1. Results of the Separate / Combine and Dual switches in Crossover Mode.
with each other to develop a dynamic curve. The solid black
line shows the curve produced when the controls are set as
shown.
In this example, the gate/expander circuit works on the
quiet parts, and the compressor and limiter work on the louder
parts. The gate/expander can range from just turning down
the quiet parts a little to a lot. The compressor and limiter are
a lot more flexible when used separately at different thresh-
olds, even though they have the same job of keeping the loud
stuff under control. Got it?
2's output, Channel 1 is still outputting
the lows which might be valuable to a
bass player running a full range along
with a bass bin (see Figure 1).
Figure 2 shows how the gate/
expander, compressor, and limiter all
can work together on the same pro-
gram material in a single channel. The
vertical axis is the output level, and the
horizontal axis is the input level. When
all Ratios are set at 1:1, the input and
output of the circuit are the same as
illustrated by the straight diagonal line
running at 45° across the graph. Each
of the Threshold controls acts like a
“hinge point”, activating gain reduction
only when the input signal reaches the
level set by this control. The Ratio
controls how much of an “angle” the
hinge will bend, or more realistically
how much gain reduction will occur
once the threshold is reached. Graphi-
cally, the ratio can swing this hinge
from 45° (no processing) to almost 90°
(full ratio). It is also possible, by
adjusting the Thresholds, to have each
of these circuits overlap and interact
Figure 2. Compressor / Limiter / Gate Input to Output Graph