Rane Music Pedal G4 User Manual

Manual-4

The G4 has 3 modes: Gate, Ducker or downward Expander.

Side-chain Detector
The side-chain detector compares a  reference signal, commonly 

referred to as the key signal, to the Threshold in order to deter-

mine the response of the Gate/Ducker/Expander. This reference 

signal may be a version of the main input (Internal side-chain) 

or another signal altogether (using the External side-chain 

inputs).

Two types of detection are used in the G4:

•   Peak detection is used in Gate and Duck modes to accurately 

capture and reproduce transients.

•   True rms detection with a fixed 35 ms averaging time con-

stant is used in Expand mode. 

The look ahead detector works as follows: the main signal is 

delayed, while the side-chain signal is not delayed. This delay is 

extremely short (a few millionths of a second) and can’t be heard. 

The G4 examines the signal in advance and determine the ap-

propriate response before an event (see Figures 2 and 3). This 

action allows the Gate and Ducker to turn on before a transient 

occurs. Pre-ramping the signal allows the main signal to be 

gated-on as the signal reaches the threshold.

Look ahead pre-ramping serves two purposes: 

•   Leading edge wave shape is preserved above 1 kHz (see 

Figure 2). 

•   It is possible to tighten up the sound of frequencies below 

1 kHz without the annoying click resulting from deep gate 

depth, high threshold and instantaneous attack settings (see 

Figure 3).

Gate Mode
A Gate operates by turning a signal down a fixed number of 

dB (known as depth) when the key signal drops below a set 

threshold.

Figure 1 shows the waveform and envelope of a gated signal. 

The leading edge of the envelope is the attack time (0 to 250 

ms). The hold time (0 to 3 seconds) determines how long the 

gate remains open after the signal goes below the set threshold. 

The release rate (25 ms to 2 seconds) determines how rapidly 

the Gate closes after the hold time has expired.

The attack setting is equal to 3 time constants, or the time 

it takes to reach 95% of the final value. Because the attack is a 

time constant, it takes the same period of time to reach 95 % 

of final value regardless of the Gate depth. This means the Gate 

will open in the same period of time from a depth of 80 dB or 

6 dB.

The minimum hold time is 25 ms and is based on two 

parameters:

•   The peak detector uses instantaneous attack and a fixed  

25 ms hold. This prevents cycle-to-cycle “chatter” at low 

frequencies. 

•   The hold time after detection is adjustable from 0 ms to 3 

seconds, giving a minimum hold time of 25 ms and a maxi-

mum hold time of 3.025 seconds.

The release rate is in dB/sec. The front panel setting refers 

to the length of time it takes to ramp 10 dB. If the release rate is 

set to 250 ms, then it takes: 250 ms to ramp 10 dB, 125 ms to 

ramp 5 dB and 2 seconds to ramp 80 dB.

1. To reduce microphone bleed, handling noise, electrical hum 

or incidental back ground noise. Microphones continue to 

pick up extraneous noise even when the intended signal is 

not present. A Gate effectively closes the microphone in the 

absence of the expected signal. Side-chain filters further help 

identify intended versus extraneous content by limiting the 

frequency response to the frequencies of interest. 

•   Clean up bleed between drum microphones

•   Automatically gate speech microphones on/off

•   Silence noisy guitar amps between songs.

2. To modify the sound of an instrument. To soften the sound, 

use a longer attack, lower threshold and/or reduced depth. To 

tighten up the sound, use a shorter attack, higher threshold 

and/or increased depth.

•   Fast attack settings tighten the sound of a drum or percus-

sion instrument.

•   Short hold and fast release times give that ultra-cool 80’s Phil 

Collins drum sound. 

3. To synchronize two sounds. Use the external side-chain 

inputs to key one input based on an a secondary input. 

•   Attach a piezo transducer to a drum and use it as an external 

side-chain input to accurately gate the drum mic on and off.

Figure 1: Gate Envelope