How to Compress Vocals

How to Compress Vocals

When compressing vocals try various settings including soft and hard-knee to find what works best for the recording you have. Also, try both saturation and compression, as well as a combination of the two to see if the character of the saturation fits the vocal well.

Basics of Compression

Real quick let’s cover some compression basics – your ratio is the input to output relationship -so 2:1 means that for every 2dB of input you’ll get 1dB of output.  This relationship begins once the signal crosses the threshold, and how quickly before this compression begins is the attack time.

Once the signal falls back below the threshold, the release time determines how long for which compression continues.

Lastly, the range will be the total amount of compression that can occur – so if set to 5dB, I can only ever achieve 5dB of attenuation.

Soft vs. Hard Knee

When compressing your vocal, you’ll want to decide on either a hard knee or soft-knee setting – a soft-knee results in more gradual compression that becomes more aggressive the louder the signal.  Hard knee is more like an on or off switch for the compression.

Soft knee settings have a more classic sound, somewhat like analog equipment.  Hard-knee settings sound more modern and should be used for more modern genres.

Attack and Release Settings

When compressing the vocal, the attack and release settings do a lot to the timbre of the vocal – for example, a long attack will cause less compression while letting transients pass through unaffected.   A short release causes the level to go back to normal quicker, causing retention to details.

For vocals, I like to use a quick attack and moderate release – this lets me capture the majority of the vocal, but while retaining some detail due to the release time.

Internal Side Chain

If you want a certain aspect of your vocal to cut through your compression, use the internal side chain to attenuate that part of the signal. Granted this frequency will still be compressed when attenuation occurs, but it will no longer be able to trigger the compression.

So say I want the vocals’ high frequencies to be a bit more present, I can use a low-pass internal sidechain filter to accomplish this.

External Side Chained Mix

You can use an external side chain to trigger your vocals compression – meaning a different signal from an external source is read by the compressor.  When it comes to vocals, I can place a compressor on a source that’s competing with the vocal, like the mix bus.

Then I’ll use the vocal as the external side chain, in turn compressing the mix bus whenever the vocal is present – causing it to cut through.

Saturation vs. Compression

When compressing your vocal, you may be trying to decide between saturation or compression – saturation is soft-knee compression combined with harmonic distortion, whereas compression is just compression.  Saturation results in a fuller, slightly louder sound due to the harmonics, but compression gives you more compression options.

Try both to see which one sounds better on your vocals, and also combine the 2 to find a good balance between them.

Crisp Parallel Compression

If you want your compression to result in a crisp sounding vocal, you’ll need to use parallel compression on the high frequencies – to do this set up a bus or aux send.  On the auxiliary track attenuate up to about 5kHz with an HP filter, then heavily compress the signal.

Use the auxiliary’s channel fader to blend this heavily compressed high-frequency range back in with your original vocal.

Thick Mid Vocal

The same concept used for creating a crisp vocal can be used to make a full mid-range – in this case, use both high and low pass filters to isolate the mid-range and then compress heavily.  Again, blend this compressed signal back in with the original vocal.

I like to use optical compression for this since I find that it blends the signal in a really pleasant way.

Vocal Rider than Compression

If you want a lot of control over your vocal’s dynamics, but you don’t want to resort to aggressive compression, combine a vocal rider with compression.  The vocal rider more or less automates the level of the vocal within a fixed range, controlling the dynamics without affecting the vocal’s peaks.

Then the compression compresses the already controlled signal, resulting in less of a need to aggressively compress.

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