Specifications
Manual-6
Making Connections
e C4 features auto balanced/unbalanced XLR and ¼" TRS 
input and output jacks, permitting connection to virtually any 
mixing console. Side-chain inputs are also auto balanced/unbal-
anced, on ¼" TRS only. Dynamics processors typically connect 
using a mixing console’s insert points (send/return), although 
they can be used in-line, such as when compressing or limiting 
an overall mix, for example.
MIC INPUT
INSERT SEND
INSERT RETURN
INSERT SEND
INSERT RETURN
INSERT SEND
INSERT RETURN
INSERT SEND
INSERT RETURN
INSTRUMENT IN
SUB GROUP 1
SUB GROUP 2
CH 1 SIDE-CHAIN
CH 1 INPUT
CH 1 OUTPUT
CH 2 OUTPUT
CH 2 INPUT
CH 2 SIDE-CHAIN
CH 3 SIDE-CHAIN
CH 3 INPUT
CH 3 OUTPUT
MASTER
STEREO LINK
SLAVE
CH 4 SIDE-CHAIN
CH 4 INPUT
CH 4 OUTPUT
MIXER
C4
BASS
MIC
Figure 11. Connection to a mixing console.
MIC INPUT
INSERT SEND
INSERT RETURN
CH 1 SIDE-CHAIN
GRAPHIC EQ
CH 1 INPUT
CH 1 OUTPUT
MIXER
C4
6
–
4
2
1
±6
4
0
1
2
+
6
100
2
4
8
6
ME 30B
40031.525 40 6350 10080 160125250200315 12.5k1k630500800 1.6k1.25k 2k 3.15k2.5k 5k4k 8k6.3k 10k20k16k
MASTER CONTROL
POWEROL LEVELRANGEBYPASS
±12
12
–
8
5
2
8
0
2
5
MICROGRAPHIC
EQUALIZER
+
12
Figure 12. Using an external equalizer in the side-chain.
Front Panel Controls
Each channel of the C4 features the following meters and con-
trols:
Side-chain and Gain Reduction Meters
8-3 -1 12 42-6-12118
dBrReduction dB
TH
is triple-function meter displays the side-chain level, threshold 
indication and amount of gain reduction being applied. It allows 
you to see at a glance exactly what the compressor is doing at all 
times.
Side-chain Level Display
In Compressor mode, the oating meter displays the side-chain 
level relative to the reshold (dBr), making it easy to gauge how 
close the signal is to the onset of compression. e dBr indicators 
light from left to right as the signal approaches the threshold. At 
threshold, the yellow TH indicator is lit. Above threshold the 
TH indicator remains lit and gain reduction occurs. Side-chain 
meter ballistics follow the rms detector time constant of 30 ms.
In Dynamic EQ mode, the side-chain meter displays the 
relative dierence between the broadband program material and 
the bandpass signal dened by the PEQ, as compared to the set 
reshold.
Example: With THRESHOLD set to -15 dB, the TH indica-
tor lights when the sibilant portion of the program material is 15 
dB below the broadband program material. If the sibilants are 
18 dB below the broadband material, then the –3 dBr indicator 
is lit.
Gain Reduction Display
e Gain Reduction meter displays the amount of gain correc-
tion presently applied to the signal, lighting from right to left as 
the amount of gain reduction increases. In Compressor mode, 
this meter display the amount of gain correction being applied 
to the broadband program material. In De-ess mode. this meter 
shows the amount of gain correction being applied to the dy-
namic EQ (DEQ) in the main signal chain. is meter does not 
reect any gain reduction occurring due to limiting.
Gain Reduction meter ballistics follow the actual gain cor-
rection value as determined by the THRESHOLD, RATIO, 
ATTACK, RELEASE and KNEE controls. Gain reduction may 
be indicated when the reshold indicator is o, as attack and 
decay rates may dictate continued gain reduction even when the 
rms level is below threshold.
1-CONDUCTOR SHIELDED CABLE
1-CONDUCTOR SHIELDED CABLE
T = SEND
R = RETURN
S = SHIELD
++
SEND
RETURN
++
SHIELD SHIELD
SHIELD
Send/Return Cable Wiring (Insert Cable)










