Manual-6
Duck Mode
Ducking reduces the level of a signal by a certain amount (the
depth) when the side-chain key signal exceeds a set threshold.
Ducking is useful for voiceover and instrument solo applications.
Example uses
• Automatically duck music when an announcement is made.
Connect the music signal to the main input, connect a signal
from the announcement microphone to the side-chain key
input. When the announcer speaks, the key input exceeds the
set threshold, and music is automatically turned down.
• Automatically duck the bass by a few dB every time the kick
drum is hit. Connect the bass to the main input, connect a
signal from the kick drum to the side-chain key input. Use a
relatively shallow depth.
Figure 5: Ducker
Kick Drum Attack Example
e pictures below show the aect of attack time on the leading
edge of a kick drum. e blue trace shows the Gate input signal.
e yellow trace shows the Gate output signal. e time dier-
ence between the two signals represents the total propagation
delay through the Gate. e Gate reshold is set to about 80%
of the peak value. e Gate Depth is 20 dB.
e rst complete cycle of the kick drum denes its sound, as
subsequent cycles are considerably lower in amplitude. e kick
drum’s sound is signicantly changed if the gate can not accu-
rately capture the rst cycle. Look ahead without ramping often
causes an audible click at fast attack and moderate to extreme
depth settings. Only look ahead pre-ramping – as done in the
G4 – accurately reproduces the 1
st
cycle of a kick drum without
adding excessive delay or signicantly altering the leading edge.
107405
©Rane Corporation 10802 47th Ave. W., Mukilteo WA 98275-5000 USA TEL 425-355-6000 FAX 425-347-7757 WEB www.rane.com
e above graph shows the operation of the Ducker. A
Ducker works the opposite of a Gate. e signal is attenuated
when the side-chain key input goes above threshold. In the above
example, the dashed-line green trace shows the signal being
ducked. e solid-line red trace shows the external key input.
e threshold is set at –20 dBu. When the key input goes above
-20 dBu, the main signal is ducked by an amount set by the
depth control, in this case around 45 dB.
Note: All applications of ducking use the external side-chain key
input.
1m
20
10m
100m
1
5
V
-80
+20
-70
-60
-50
-40
-30
-20
-10
0
+10
-60 +20-55-50 -45-40 -35-30 -25-20 -15-10 -5 0+5 +10 +15
SIDE-CHAIN INPUT
DUCKED SIGNAL
INPUT dBu
O
U
T
P
U
T
d
B
u
The rst gure shows the response with a 0 ms attack time. The lead-
ing edge is dened by the look-ahead ramping. Note the leading edge
of the output is almost identical to the input signal.
The second gure shows the response with a 1 ms attack.
The slower rise time softens the sound of the leading edge.
