Today we’re talking about Gates!
This one is a fairly easy topic because we are already familiar with what gates do. They are intuitive in the sense that we use them in everyday life to keep things from getting in or getting out of a specific area. Think of a gated community. The gate of a gated community allows members of the community to enter, and it keeps those who are not members out. A baby gate prevents a baby from passing, but an adult can walk right over it.
A Gate is used to allow audio levels over a specific threshold to pass, and prevent audio below that threshold from making it through. Pretty simple right? In the compressor lesson we covered what a threshold is (the dB level at which the tool becomes active/ inactive). We also covered attack and release as well (how much time is given for the tool to start working, and how long the tool stays active ). Lucky for us, a Gate uses almost the exact same controls! You’ll begin to see a common theme with controls in the audio world the more you explore the more commonalities you’ll find between all the tools.
A lot of these controls should already look familiar to you if you’ve allowed along in the series so far. Ratio, threshold, attack, release, knee, and lookahead were all discussed in compressors and limiters. Not to worry though because their concept is exactly the same. The tool may have changed but the functions of the knobs have not!
The new settings we’ll be covering with the Gate is Range and Hold.
Range - Is the amount of level in dB the audio will be reduced once the level drops below the threshold.
Hold - is like a mix between attack and release. Once the audio passes above the threshold, Attack is how long it takes for the gate to be all the way open. Once the audio falls back below the threshold, Hold will act as a short delay in time to keep the gate open before release begins to close the gate.
Attack is how long it takes for the gate to open.
Hold is how long the gate stays open before it begins to shut.
Release is how long it takes the gate to fully close.
Range is how much the audio is turns down once the gate is fully closed
MOST gates do not actually have a ratio setting. So we won't get too far into why this specific gate does. The most important and universal gate settings are the ones I covered above. An expander is the opposite of a gate and for this we need a ratio. We’ll save the expanders for another day.
Applied example:
Our current settings for the gate below are as follows:
Threshold = -34dB
Attack = 50ms
Release = 50ms
Hold = 2ms
Range = 100dB
As you can see in the above image our threshold is set to -34dB.
While our audio is sitting at a solid -35.8dB
If we were to add 2dB more gain, this will cause our audio signal to breach the -34dB threshold thus opening the gate. You can now see that the audio is now above the threshold and is bright blue and visible
Audio is now at -33.8dB
This is the whole use case for a gate. Now what are some good examples as to when to apply a gate you may ask?
Let's say you were recording vocals and when the vocalist wasn't singing you could hear the floor noise or hissing of the mic. Adding a gate at the beginning of your recording chain will duck out all the unwanted noise.
As a matter of fact, when I record the youtube videos for each of these lessons I use a gate to prevent unwanted background noise from getting into the audio signal. Neighbors driving by with loud trucks, my ceiling fan that has an annoying squeak to it, my AC, heck I can even do laundry while I record a video but you wouldn't know the difference because the gate is keeping all the unwanted noise from activating the microphone.
Remember though if your microphone can hear it, it can still bleed into your recording. Your voice is loud enough to open the gate, but the sounds happening in the background are still there and the gate is now open. If the gate is open all audible sounds will be recorded.
Keeping this in mind, the proximity effect plays a big role here. Since I am closer to the microphone I am inherently louder than the background noise. Just because i am louder doesn't mean there isn't background noise, it just means the background noise is harder to hear. It will still make it into the recording if the microphone can hear it.
A gate is a safety net for the inbetweens when you aren't actively singing or speaking. A gate is for in between your words and when there is noise that picks up in between the quiet parts.
Another example
We have all the same settings as the first example but this time we have a Range of 10dB
Since our range is only 10dB, when the audio falls below the threshold, the Gate will only reduce the volume by 10dB. That being said, and remembering that our threshold is set to -34dB and our audio signal is at -35.8dB, We can see in the images that since our audio is below the threshold it has been effectively reduced by 10dB, the exact range that we selected!
If you want the audio turned down a little bit then use a smaller range setting. If you want the audio to drop to science when the gate is closed, use a larger range setting.
As an experiment with gates and their utility. Try plugging in your microphone and without talking, turn the volume up enough that you can hear your room, maybe hear what's going on in the room next to you or hear the AC running. Then, apply a gate and hear how it gets rid of the background noise until something loud enough breaks the threshold and opens the gate letting all the audio through again. (This would be heard best with closed back headphones.)
This lesson is pretty short and sweet because gates are super easy to use and really only have one purpose, to prevent unwanted floor/ background noise from getting into our recordings!