Noise Gate Visualizer

To begin, take a peek at the Noise Gate Visualizer, which illustrates what a detector do in determining whether it should allow a sound into your mix. Using this widget is interactive, you can play around with it and even make changes using your computer keyboard instead of your mouse (for quick adjustment). The visualizer demonstrate how a noise gate work and reveals how settings like timing, hysteresis, and threshold impact your signal.

Note the big oscilloscope-like display in the middle, displaying the detector history. The cyan line is the open threshold. Drag it up and down to adjust the level where the gate opens. Below that is a dotted amber line showing the close threshold (taking into account hysteresis). As long as the incoming signal remains below the cyan line, the gate will remain closed. Once it crosses over the cyan line, the gate opens. If it then drop back below the amber line, the gate begins preparing to close (assuming it holds there long enough for hold time).

How to Use the Noise Gate Visualizer

The test signal selector is on the right. There are three options: Snare Drum in Noisy Booth; Sustained Guitar with Background Hum; Vocal Phrase with Breath Noise. These each give you a different signal profile and noise floor that you can feed into the gate and observe its response. Pressing one of the buttons loads the relevant simulation and allows you to listen to it as well as watch the gate respond to realistic scenarios.

Use the controls below the source selector to adjust the gate’s behavior. To start with, there’s an open threshold slider that set the main trigger level. Then there’s the hysteresis gap slider which creates a difference between the open and close thresholds; thereby stopping the gate from constantly chattering if the signal is hovering near the threshold. Finally, you have attack, hold, and release sliders that control the envelope timing. Attack is the speed at which the gate opens. Hold is how long the gate stays open once the signal falls away. Release is how smoothly the gain return to zero.

Click Feed the detector to turn on the simulation. It will play through the test signal you chose over and over again. You can change parameters while this is happening, so it’s live. To run just one event under controlled conditions, click Audit one gate cycle. This will go through your pre-set list of levels until it hits all the threshold crossings, and let you see how the gate makes its decisions free from a constant noise floor.

Finally there’s a master volume slider (output level) and below that the floor census tool. To use it, click Measure the low-level bed which will sample the lowest levels in the currently running test signal. After measuring, you’ll be able to click Set open line 6 dB above, which will set the open threshold slightly above the measured noise floor with one click. This helps you start setting up quickly.

If you want to do it all mouse-free, you can use keyboard shortcuts. To adjust the open threshold with the up and down arrows, focus on the oscilloscope display. Use G to turn the detector feed on/off. Use A to perform an audit for one gate cycle. Use N to measure the noise floor, which will apply the recommended threshold using M. Hit escape to halt any current processing and quiet the sidechain.

Set the hysteresis to zero on the vocal source. You may notice the gate ‘chattering’ as the breath noise hovers around the threshold point. Raise the hysteresis to 8, 12dB and note that the gate now becomes stable. The vocal phrase benefits from a longer hold to preserve the endings of words, whereas the snare drum, with its fast attack and short release, serves as a contrast. Experiment with these timings to see how the natural decay of each instrument is shaped by the timing parameters.

When you’re not sure where to begin with the threshold, use the floor census feature. Let the widget look at the noise bed and give you the suggested margin. Then tweak it up or down yourself to taste. Open it a little more if you would like to capture some of the quieter details, raise it if you’re still hearing the background noise. You can see exactly when the signal goes over those critical lines on the scope’s display.

At the very top there’s also the How to play button which opens up an expanded version of the how-to guide to explain further what each control does and what conventions are used in this particular visualizer. So if you’re curious about exactly how the floor estimation algorithm works or just need a reminder of what the hold timer do, give it a read. There’s also the fullscreen button that expands the widget for a cleaner look at the oscilloscope itself, which can come in handy when fine-tuning your threshold position.

Play around with every setting slowly and see what it does on both the visual as well as audio side of things. To really get into using noise gates properly in mixing you want to know not only how each affects the other but also the threshold in relation to attack, hold and release. Begin with the defaults, then tweak one knob at a time so that you can focus on each individual change and have a feel for the tool before long.

You should of seen it by now. Actualy, use G to turn the detector feed on/off. Use A to perform an audit for one gate cycle. Use N to measure the noise floor, which will apply the recommended threshold using M. Hit escape to halt any current processing and quiet the sidechain.

All this luxurius settings can be confusing. Setting it up based off these rules is better then guessing. Just make sure you don’t miss the moddern features of the gate. It can absorbs some of the hiss if you do it right. Use the two adult-sized sofa for your studio setup to feel comfortabley.