Vocals are the focal point moreso with rap than arguably any other genre. The entire song revolves around that vocal and, as such, rap vocals are meant to be at the forefront of the mix. We can keep that vocal on top of the beat and instrumental through compression, so let’s talk how to compress rap vocals.
How to Compress Rap Vocals
By virtue of how they’re recorded, rap vocals typically don’t have nearly as much dynamic range as a more melodic vocal part. This is because they’re generally delivered within a more limited range, so less air, force, and movement is necessary during the delivery.
Because of this, we don’t need to be as aggressive with the compression settings to get good results, though your individual performance may vary. Let’s get into the best settings for how to compress rap vocals.
Before we begin with threshold, let me reiterate the importance of gain staging ahead of sending your vocal (or any audio) into any plugins/processing. An average vocal level of -18dB is ideal for getting the best results from the compressor or any other type of processing. This yields a better sound from the plugin (in many cases with plugins modeled after analog gear) and keeps the levels of your overall mix well below clipping which leads to a better sounding mix and master.
I put together a complete gain staging cheat sheet, so refer to that for more information.
Here’s a snapshot of the best settings for how to compress rap vocals:
These settings work extremely well in how to compress rap vocals for presence in the mix but let’s go through each one parameter by parameter to better explain where we’re setting it and why we’re setting it there.
Threshold
The threshold is the level the vocal must reach before compression begins.
Setting the threshold at roughly the quietest practical vocal part (but above breaths and background noise) compresses the entire range which helps to keep that vocal up front.
Admittedly the peaks will get brought down more aggressively, but when we pair this kind of threshold point with an aggressive ratio, it helps to keep that rap vocal constant so no words or syllables or lost but without sounding robotic.
Ratio
With most vocals, the first compressor in the vocal chain is the one I’m using to get a hold of the most extreme peaks and bring a sense of cohesion to the vocal.
As such, the first compressor I’m using (see how many compressors to use on vocals) has the most aggressive ratio.
Specifically, when compressing rap vocals I like an 8:1 ratio. This means for every 8dB the vocal exceeds the threshold at any point in time, they get reduced to an output of 1:
Admittedly this is an aggressive ratio, but again, this is to control any extreme peaks present on certain words, phrases, etc. while still keeping some semblance of dynamic range.
You’ll very likely see a gain reduction of over 10dB on the most extreme peaks in the vocal, but this will depend on your specific vocal.
I’ll typically follow this initial up with a second compressor, something like an optical compressor like the Waves CLA-2A which doesn’t even have a ratio setting. Instead you just set the input to achieve an additional 2-3dB at most of gain reduction (on the second compressor).
But I digress and that’s all to say on the optional second compressor, let’s get back to how to compress rap vocals with that main/initial compressor by covering the knee.
Knee
The compressor’s knee determines how strictly that threshold is enforced.
A softer knee bends that threshold point so that a lighter ratio of compression is enforced as the vocal approaches the threshold.
This gradual and dynamic ratio yields more natural results particularly with audio with more complicated dynamics like a vocal. This is measured in decibels and the exact range of decibels your compressor features will vary (my go-to, FabFilter Pro-Q has a knee which ranges from 0-72+dB).
Regardless, you’ll want to opt for a softer knee (higher in decibels) with your vocal so you’ll get less “all or nothing” compression which is more common with a hard threshold.
Attack
Attack determines how quickly compression engages once that threshold is exceeded (admittedly the attack and knee work together here).
If you set the attack too short/fast, the compression instantly engages and the transients which are typically part of those peaks get snapped down. Transients are the high frequency initial sounds we hear with any sound (see what are transients for more information).
On vocals, the transients are the sharp percussiveness on certain consonants which pokes through and helps that vocal assert itself in the mix.
Therefore, to preserve those transients and keep the vocal nice and clear in the mix, an attack time of 1-3ms is enough to allow those transients to assert themselves for that split second before the compression brings the rest of the peak down..
If the vocal isn’t poking through as much as you’d like here, try adding a small boost around 4k on your vocals EQ as I covered in my tutorial on how to EQ hip hop vocals.
Release
50ms is a good release time when compressing rap vocals.
This is how long it takes that compression to disengage and the vocal to go back to its initial state once the level drops below the threshold.
Setting this too long results in an awkward in between state, but setting this too fast can result in a pumping effect which we generally don’t want on vocals.
Basically the rule of thumb is to generally not let the listener hear the compressor working, so to avoid compression artifacts on a vocal, 50ms works well.
Gain
An important parameter we oftentimes forget about or set incorrectly is the output or make up gain.
Manually set this to match the average -18dB post compression, the same as you had coming in. Essentially the level should sound roughly the same with the compressor on or off if you set the output gain correctly. This gets the vocal’s level in its best shape for whatever the next set of processing is (like that second compressor, if necessary).
That’s it on how to compress rap vocals effectively. With those settings, your rap vocal should be sitting much better in your mix with a lot more power, control, and cohesion behind it. If you’re still losing a word here or there or it’s still feeling a little weak, try following it up with a second compressor. That second compressor can be an opto/optical style like I mentioned earlier or a second instance of the first compressor you used.
In the latter’s case, I’d recommend using a much lighter ratio as this second compressor is meant to simply smooth out the remaining peaks and achieve a more constant level, not squash them into an audio sausage.
If compression alone isn’t keeping your rap vocal where you want it, check out my tips for achieving an up front vocal to ensure that vocal stays in the front of the mix where it belongs.