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Chapter 4 Dynamics processors 99
Use Noise Gate
In most situations, setting the Reduction slider to the lowest possible value ensures that sounds
below the Threshold value are completely suppressed. Setting Reduction to a higher value
attenuates low-level sounds but still allows them to pass. You can also use Reduction to boost
the signal by up to 20 dB, which is useful for ducking eects.
The Attack, Hold, and Release knobs modify the dynamic response of Noise Gate. If you want
the gate to open extremely quickly for percussive signals such as drums, set the Attack knob to
a lower value. For sounds with a slow attack phase, such as string pads, set Attack to a higher
value. Similarly, when working with signals that fade out gradually or that have longer reverb
tails, set a higher Release knob value that allows the signal to fade out naturally.
The Hold knob determines the minimum amount of time that the gate stays open. You can use
the Hold knob to prevent abrupt level changes—known as chattering—caused by rapid opening
or closing of the gate.
The Hysteresis slider provides another option for preventing chattering, without needing to
dene a minimum Hold time. Use it to set the range between the threshold values that open
and close the gate. This is useful when the signal level hovers around the Threshold level, causing
Noise Gate to switch on and o repeatedly, and producing the undesirable chattering eect. The
Hysteresis slider essentially sets the gate to open at the Threshold level and remain open until
the level drops below another, lower, level. As long as the dierence between these two values
is large enough to accommodate the uctuating level of the incoming signal, Noise Gate can
function without creating chatter. This value is always negative. Generally, −6 dB is a good place
to start.
In some situations, you may nd that the level of the signal you want to keep and the level of the
noise signal are close, making it dicult to separate them. For example, when you are recording
a drum kit and using Noise Gate to isolate the sound of the snare drum, the hi-hat may also open
the gate in many cases. To remedy this, use the side-chain controls to isolate the desired trigger
signal with the High Cut and Low Cut lters.
Important: The side-chain signal is used only as a detector/trigger in this situation. The lters are
used to isolate particular trigger signals in the side-chain source, but they have no inuence on
the actual gated signal—the audio being routed through Noise Gate.
Use the side-chain lters
1 Click the Monitor button to hear how the High Cut and Low Cut lters will aect the incoming
trigger signal.
2 Drag the High Cut slider to set the upper frequency.
Trigger signals above this are ltered.
3 Drag the Low Cut slider to set the lower frequency.
Trigger signals below this are ltered.
The lters allow only very high (loud) signal peaks to pass. In the drum kit example above, you
could remove the hi-hat signal, which is higher in frequency, with the High Cut lter and allow
the snare signal to pass. Turn o monitoring to set a suitable Threshold level more easily.