You do not need twenty plugins to make a rap vocal sit right. You need a repeatable chain, applied in the right order, with the recording done well enough that the chain has something to work with.
Fix the source first
Cut breaths that distract, tighten obvious timing drift, and comp the best syllables from your takes before you touch an equalizer. Editing is unglamorous and it does more for a vocal than any plugin.
Step one: subtractive equalization
High-pass around eighty to one hundred hertz to remove rumble. Find the frequency where the vocal sounds boxy, usually between two hundred and four hundred hertz, and cut it two or three decibels with a wide band. If there is a resonant ring, sweep a narrow boost to find it, then cut it. Do not add brightness yet.
Step two: compression in two stages
One compressor doing twelve decibels of gain reduction sounds squashed. Two doing four to six each sounds controlled. Set the first with a fast attack and medium release to catch peaks, and the second slower to level the overall performance. If the vocal starts sounding lifeless, you are compressing too hard rather than too often.
Step three: de-essing
Rap delivery is consonant-heavy, and the brightness you add later will exaggerate every S. Place a de-esser after compression, target the five to eight kilohertz region, and reduce only until the sibilance stops jumping out. Over-de-essing gives you a lisp that cannot be undone.
Step four: additive equalization
Now add air with a high shelf above eight kilohertz and, if the voice is thin, a small presence boost around two to three kilohertz. Additive moves after compression change the character; the same boost before compression just makes the compressor react to it.
Step five: saturation for density
Light saturation or tape emulation adds harmonics that let the vocal cut through a busy beat without raising the fader. This is usually what people are chasing when they say a vocal sounds “expensive.”
Step six: time-based effects on sends
Use sends, not inserts, so you can control the wet level independently. A short room reverb glues the vocal to the beat, a slap delay of eighty to one hundred twenty milliseconds adds width, and a longer plate suits hooks. Filter the low end out of your reverb return so it does not muddy the mix.
Ad-libs, doubles, and the hook
Double the hook and pan the doubles wide, keep the doubles four to six decibels below the lead, and process ad-libs more aggressively than the lead so they read as a separate layer. This contrast between verse and hook is what makes a chorus feel like it arrives.
Reference and commit
Pull up a commercial track in the same subgenre, match perceived loudness, and compare. Then print the chain and move on. A finished song with a good-enough vocal beats a perfect vocal on a song nobody hears.