Compression is a way to detect and manage loudness peaks in audio recordings. Learn how we can use this tool to process voice recordings in Fairlight, in DaVinci Resolve, with this tutorial.
For example, imagine you're dealing with a mostly quiet piece of dialogue with a few parts where the conversation gets a little over-loud. You'd want to raise the overall level of the tracks to make the voice more present in the mix, however doing this without any other adjustments would cause the louder parts to peak, reducing the overall quality of your recording. This is where you'd want to use a compressor.
Another way of looking at compression is that you're reducing the dynamic range of your signal to create more presence in the mix, and/or to smooth out the different levels in a recording.
To access the compressor you'll need to open up the Dynamics panel by double clicking Dynamics located in the mixer. You'll notice right away that this section includes a limiter and expander/gate. All of the sub-sections in dynamics are designed to manage audio levels, but in this tutorial we'll just be going over the basics of the compressor.
How to Compress Audio
Once you turn on the compressor, you'll see two lines appear in the graph. The green/yellow diagonal line represents the audio signal and the vertical blue line, the threshold. This means the compressor will kick in anytime the single passes that intersection.
Moving to down you'll see that the default for threshold is -15db. This is a good level to start with. On the right, you'll see a Ratio knob. This controls how much the signal will be reduced by once it hits the threshold. 2:1 or 3:1 are good starting places for dialogue, and using too much will end up with your audio sounding artificially pushed down.
The way to understand ratio and its relationship to threshold is easy. If you set your ratio at 2:1 and your threshold at -15db, you're saying for every 2db over your threshold, you'll be reducing it by half.
Below this you'll see Attack, Hold, and Release.
- Attack is how quickly the compressor acts once hitting the threshold.
- Hold is long the compressor stays on for after the signal is back below the threshold.
- Release is the time it takes to go back to the signal being uncompressed.
Fairlight does a great job with these default settings. That being saying said, you should play around with the all the features to really get used to what each one does and how they affect the sound.
Managing Levels with Gain Reduction, Gain Make up and Output.
Next to the graph, you'll see three bars of gain reduction, and the meter in the middle is dedicated to the compressor. This measure the amount of compression applied to your clip. If you were to playback your audio and monitor the level with the Gain Reduction Meter, it should be, for the most, inactive. This is because while you have louder aspects of a recording it's in comparison to the quiet parts, and only until you raise the output by adjusting the Gain Make Up will the louder parts start to peak.
The next step is to increase the overall volume of the track using the Gain Make Up tool. The compressor makes it possible to manage the audio that peaks by reducing any audio that goes above our set threshold of -15db. Start by adjusting this to -5db and listen back. This is generally good starting point for a moderate recording. Remember to use your ears, they're your best friend and will give you just as much or more feedback as your graphs and meters.
Lastly, with the use of the Output meter, you can get a clear visual representation of the strength of the signal at any given time. You'll want to have your dialogue to sit around -6db to -15db, though most YouTubers aim for -12-db. This is because YouTube likes to go ahead and normalize audio on your behalf, so that from video to video the viewer won't have to adjust your volume.
Using the compressor to adjust the levels of your dialogue is a great way to manage your sound. It's important to mention that while these tips are great starting point, all audio recordings aren't created equal. By getting familiar with the compressor, you'll have a better understanding of what adjustments are needed no matter the audio.
Creating a Dynamics Preset
If your recording setup never changes much, a preset can save you some time. Doing this in Fairlight is really easy, even though the menu looks more complicated than it actually is. Along the toolbar at the top, select Fairlight and open Presets Library, you'll be greeted with this menu (figure 3).
Since we're creating a compression preset, under Filter by, select Dynamics Presets. Next, choose which channel you want to save the changes from-in this case, I'm choosing Audio 1. The last thing to do is hit Save Now and choose a name for your preset, any name will do. I try saving presets with names that I'll understand at a later date, In this example. I've used "General Compression".
Free Video Courses: Follow Envato Tuts+ on YouTube
Tuts+ has a fantastic YouTube channel covering all things digital media. In this free course on Fairlight you'll learn how to process voice recordings.
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