It’s time to talk about how to get a professional vocal sound, using plug-ins in Pro Tools. With so many options, it’s hard to know what’s necessary, and what’s excess. It’s important to experiment and try new things when you’re recording a song, but there are a few basic tools you’ll want to get familiar with, so you can employ them like old friends when the moment calls for it.

Compression

You’re almost always going to want a compressor running on your vocal track. There’s a good reason for this: by nature, vocals are dynamic, meaning they go up and down in volume and intensity. This can be a problem when your vocals are sitting on top of instruments, which tend to stay within a reliable volume range. It makes your quiet parts hard to hear, and your loud parts jarring. Compression solves this, by keeping things consistent throughout.
It’s also important to keep Compression at the top of your chain. You’ll find that putting your Compressor under another plug-in will often render the upper effect nearly unnoticeable.

EQ
Equalization is leveling the low, mid, and high frequencies of a sound. Bringing the highs up will make for an “airier” sound, and bringing up the lows will increase the “rumbling” sounds. In Pro Tools, your EQ settings have presets, such as “Snare” or “Piano”. These are a great starting place, but slide each of the faders back and forth while you’re playing a sound, sweeping the range to find the best sound to your ear.
You can put the EQ anywhere in the chain, but you’ll hear a difference in each order. Play around with it, to see what works best.

Reverb
Reverberations are the reflections of a sound, bouncing off of surfaces. This is often mistakenly referred to as ‘echo’, in everyday applications. When you yell in a cave (which you probably do at least once a week, right?),  you’re hearing the sound reverberating off of the walls, the ceilings, and the floor.
This phenomenon can be used to great effect in sound recording, particularly on vocals. Don’t overdo it, though, unless you’re trying to make a point. Subtle reverb is more effective because it can be almost imperceptible in the mix. (This might be a good time to mention that subtlety is almost always the key to a great mix. Nothing should be too obvious or overloaded. This goes for reverb, echo, distortion, chorus, etc. Imagine that you’re trying to hide its presence.)
On most versions of Pro Tools, you’ll have to run a Dither plug-in first, to activate a reverb plug-in. This effect uses white noise to filter out excess noise on your track before reverb is applied.

Light Distortion
Let’s not get crazy here. This isn’t death metal (or is it?)! When I say distortion, I just mean a light tape saturation effect, which can be achieved with a tape simulator effect (such as the Tapehead plug-in). This will further separate your vocals from the instrumental mix, and keep them from sounding too bland or overly clear.
After you get the hang of these, try out some other effects plug-ins! Delay and echo make for great vocal sounds, and modulation effects like chorus and flanging can make for an interesting bridge or background vocal sound. These are just your basic colors. Learn the rules, so you can start breaking them!