dbx Pro 4800, 4820 manual Noise Gate, Gate On/Off switch, Max Attenuation fader

Section 6 Detailed Parameters DriveRack®

6.16 - Noise Gate

The DriveRack 4800 and 4820 provide a Noise Gate Insert that can be placed in both the Input and/or the Output section. A Noise Gate is used to remove unwanted low-level noise in a system. The basic premise behind a Noise Gate is that gain reduction or Gating will be applied to the channel unless there is a signal that is above some Threshold.

Gate On/Off switch

This turns the Gate on and off.

Threshold fader

This sets the Threshold level. If there is any signal above the Threshold, the Gate is Open, while a signal that is lower than the Threshold is attenuated. Beware of setting the Threshold too high as it can cut off the tail end of signals as they fade out (the sustain of a guitar note, a held piano chord, a reverb tail, etc.). The Threshold is adjustable between -70 and 0 dBFS.

Ratio fader

This control determines how much the signal will be attenuated once it drops below the Threshold. This ratio works opposite from that of the compressor or limiter. If a Ratio of 1:4 is selected, a signal that is 1dB below the threshold will be reduced in gain so that it becomes 4dB below the threshold. The Ratio is adjustable between 1:1 and 1:15.

Max Attenuation fader

The Maximum attenuation sets the bottom limit for gain reduction that the Gate will apply. It is adjustable between 0 to INF dB. 0 dB attenuation means that even though the Gate is “closed” there is no gain reduc- tion. INF applies an infinite amount of gain reduction (in the digital domain this is done by multiplying the signal by 0), resulting in no output.

Attack fader

The Attack parameter sets the speed at which the Gate opens once the Threshold has been crossed. It is recommended that very fast attack times be used to catch the fronts of transient signals. The Attack para- meter is adjustable between 0.1 to 200 mSec.

Hold fader

The Hold control sets the amount of time the gate is held open after the signal passes below the Threshold point. It is adjustable between 0 to 500 mSec.

Release fader

The Release sets the rate at which the gate “closes” or attenuates once the end of the Hold time is reached. Release can be adjusted between 360 and 5 dB/Sec.

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58 DriveRack® 4800/4820 User Manual