When mixing vocals there is a lot of tools you can use. In this article I'm going to talk about: EQ, De-Essing, Compression, Harmonic Enhancement, Reverb & Delay.
Step 1: EQ & De-Essing
First of all you're going to want to listen to the recorded vocal for frequencies you can cut out.
For example a boxy sounding vocal (300-500Hz) or a vocal with a strong nasal sound (Around 1Khz)
If you hear harsh "Esses" in the vocal you can apply a de-esser to cut those and smoothen the vocal out.
After you "cleaned" the vocal from the unwanted frequencies you can boost certain areas like 2-4Khz for clarity in the vocals, or 8-10Khz for an "Air" freshness in the vocal.
Step 2: Compression
A recorded vocal can have a lot of dynamics. Some loud parts and some soft parts. What you want to do with a compressor is to reduce the peaks, and raise the low parts of the vocal to make it one solid vocal.
A good starting point for compressing (rap)vocals is a ratio of 4:1, attack around 5ms and a release around 50-100ms. When mixing singing vocals you can use slower attack / release.
These are only starting points so make sure you adjust the settings to whatever your project needs.
After setting the starting-points you can compress, depending on the vocal and how it was recorded you can decide how much you compress.
3-6Db gain reduction is usually good for a rap vocal, but again, use your ears and listen to what 2db of gain reduction does to the vocal, and what 4db does etc. Also make sure you use the makeup gain to boost the volume by the amount you reduced by compressing it (4db gain reduction = 4db boost after) this allows you to hear the difference clearly when bypassing the compressor.
Step 3: Harmonic enhancement
You can use harmonic enhancement to fatten the vocal up. Harmonic enhancement basically mimics the characteristics of tube hardware etc.
If your vocal didn't get recorded with a high-end preamp, you can use harmonic enhancement to fatten the vocal and get a solid lead vocal.
However, make sure you don't overuse harmonic enhancement on vocals, a very slight amount can be enough, too much and your vocals will sound harsh, especially on high volumes.
Step 4: Reverb & Delay
After you've processed the vocal to make it sound clean and fat, it will probably sound dry and will not blend in with the other elements of the track properly. A slight reverb and/or delay can make a vocal blend in and sound smoother.
If you have trouble finding the right reverb time try this formula: 60 / Bpm = reverb-time
If you want the reverb to be longer you just multiply that by 2, do you want it to be shorter than divide it by 2. These reverb-times will be perfectly synced with the instrumental and will make the overall mix sound better.
A slight reverb and delay will also help widening the vocals. Try using a stereo enhancer on the reverb or delay, or cut the high end of the delay to give it more depth. Small things like that can make a big difference in the mix.
Keep in mind that these are only starting points, there is no magic formula that you can apply to get a certain mix, every song is different and every song might need something else.
Written by Roy "R-skillz" Wehbe
Producer, Mixing & Mastering Engineer.