Rane Music Pedal G4 用户手册

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. 

•  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

The pictures below show the affect of attack time on the leading 

edge of a kick drum. The blue trace shows the Gate input signal. 

The yellow trace shows the Gate output signal. The time differ-

ence between the two signals represents the total propagation 

delay through the Gate. The Gate Threshold is set to about 80% 

of the peak value. The Gate Depth is 20 dB.

The first complete cycle of the kick drum defines its sound, as 

subsequent cycles are considerably lower in amplitude. The kick 

drum’s sound is significantly changed if the gate can not accu-

rately capture the first 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 significantly 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

The above graph shows the operation of the Ducker. A 

Ducker works the opposite of a Gate. The 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. The solid-line red trace shows the external key input. 

The 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.

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

INPUT dBu

O

U

T

P

U

T

 

d

B

u

The first figure shows the response with a 0 ms attack time. The lead-

ing edge is defined by the look-ahead ramping. Note the leading edge 

of the output is almost identical to the input signal. 

The second figure shows the response with a 1 ms attack.

The slower rise time softens the sound of the leading edge.