Vocal compression has been made out to be an intimidating monster that lurks in effects racks. This monster brings fear, confusion, and dread to one of the most crucial aspects of your mixdown.
What if defeating that monster isn’t as hard as most often perceived?
By translating technical jargon into an easy-to-digest universal language, this simplified explanation will empower you with an understanding of vocal compression:
- What is vocal compression?
- What does it do?
- How and when do you do it?
(Plus, we’ll share some hardware and software to get you started.)
With this knowledge, you can conquer the monster and make considerable improvements to both the sound and feel of your vocal tracks and how they sit in the final mix.
What is vocal compression?
First, the technical definition.
Compression is an effect that reduces dynamic range.
Now, the simple definition.
Compression can reduce the gap between loud points and soft points. A compressor is like having a psychic engineer that knows when to increase and decrease at just the right time and in just the right way.
How does Compression Work?
Compression is made possible by the input of parameters. The compressor then automatically makes adjustments based on those parameters.
If we limit the louds, the mix as a whole can be brought up, thus making the softer parts louder without making the louder parts clip.
Why should compression be used?
No singer can maintain a consistent volume.
- They might sway or have an improper distance from the microphone.
- They also may alternate between a soft voice and a loud voice.
Compression will ensure that those softer parts don’t get lost in the mix.
Compression can also increase transient sounds, such as subtle breathing, which can really emphasize the power of a strong chorus line.
When should compression be used?
Vocal compression should be used any time there is a drastic change in volume.
Understanding Compression Functions
To better understand how to use compression, it is important to know what each and every knob does and the impact of each adjustment as it is made.
Unlike other effects, compressors are not as forgiving to those who approach it by making random and drastic knob tweeks.
Input Gain is the amount of the signal that is allowed to reach the compressor.
The threshold acts as a ceiling. Anything above the threshold will be compressed. This is how you balance out the louder parts of your vocal tracks with the softer parts.
The way to determine the threshold would be to start it out as high as it goes and then begin decreasing the threshold until you can begin to hear compression taking place. Applying too much of a threshold will result in a squeezed or restricted sound.
This ratio can be a little tricky at first. Remember that as with most things in music, it really is all about experimentation. The ratio will determine the input-to-output gain (in decibels or dB).
This is how you close/open the gap, or ratio, between the loudest parts and soft parts.
- 4:1 ratio: For every 4dB input increase there will be a 1dB output increase.
- 2:1 ratio: For every 2dB input increase there will be a 1dB output increase.
The attack will determine the speed at which the compressor engages to adjust the threshold.
If you set a smaller window of attack, you will hear breathing between phrases. Transient sounds such as this give more energy and a sensation of louder volume.
If you set a larger window of attack, the sound will be more abrupt. There will be no gradual increase. A higher attack is more suitable for a punchy kick drum.
The release will determine how fast the signal is restored to its original state once it has fallen below the threshold.
Dirty Knees, Look at these
The option of hard knee and soft knee refer visually to a curve.
A soft knee will give a more gradual and soft compression that can be pretty hard for most people to pick up on. Using a soft knee allows compression to occur before the threshold is reached, as to ease into it.
With a hard knee, similar to the attack, this will be more abrupt.
Selecting a Compressor
So which compressor is right for you?
Sorry guys, there isn’t an easy answer for that. The best way to find out is to try as many as you can in order to find the one(s) that work best for your situation.
If you are looking for a hardware compressor that is budget-friendly, the Behringer Composer Pro-XL MDX2600 is a dual-channel compressor/limiter/expander. It offers you the control to add a little old school tube warmth, has a De-Esser and other features that eliminate the need for multiple pieces of gear.
For those that want to go all out, one of the best compressors for vocals is the Distresser from Empirical Labs. You will find this compressor in most professional recording studios. And why not? It offers built-in harmonic enhancement, filtering, coloring, and amazing frequency response. While this is definitely not for beginners, once you become comfortable with the basics and decide you want more control, the Distresser will fulfill all of your wildest compression dreams.
From the makers of the Serum plugin synth, OTT is a free re-creation of a popular aggressive multiband upwards/downwards compressor. With an easy-to-understand interface, OTT also allows you to visualize the incoming and outgoing signal once it has been compressed. OTT is a free plugin that is available for both Windows and Mac O/S.
Quick Tricks & Fast Tips
- Use compression on vocals during mixdown only. Recording vocals with a live compressor does not allow room for editing the applied effect.
- Do not isolate the vocal and apply compression. You want to make adjustments based on how it fits in the mix with the rest of the track.
- Good compression shouldn’t be detected. If the vocals sound squeezed and limited, you’ve over-compressed. This is caused by the attack time being too fast.
- A tonal compressor, with a slow attack, will help smooth your vocals without losing the transients.
- A dynamic compressor, with a fast attack, will help control high peaks in volume.
How to compress Vocals: Final Thoughts
When you have drastic volume changes in your vocal tracks, it will no doubt affect the dynamics. Similar to watching TV, when the show goes to a commercial and it is drastically louder than the show itself, you instantly scramble for the remote to turn down the volume. It is annoying and disruptive. The same goes with music.
By closing the volume gap you can now hear the softer parts without being blown away by the louder parts. This makes for a much more enjoyable listening experience.
Give it a try, experiment, and in no time you will be able to approach vocal compression with confidence and your end result will be dynamically enjoyable.
If you have any questions about how to compress vocals, comment below!