Ad-libbing is having to make things up on the fly, in the middle of a performance, in real time, right in front of everybody with lot of opportunities to stumble or get tongue-tied, freeze up, go blank, on stage or in the studio .
That’s exactly why most professionals don’t, and you shouldn’t either.
The “skill” is a nice one to have, but it’s importance is way over-rated. It’s way more important to nail that song without any mistakes, than it is to be really good at making stuff up on the fly. At the end of the day nobody knows or cares if you’re making it up or if you wrote it all down a week ago.
Adlibs are needed more on slower tracks like trap beats. But it really depends on the artist and the direction of the song. They add a great amount of flavor and energy to a track if done right. If not, they can easily take away and distract from the music and the feeling.
There’s a difference between
1. Back Ground Vocals:
Used randomly through a song to enhance the lead vocals, usually in a rhyme.
2. Double Vocals:
Singing the exact performance through an entire song.
Rand words, notes or noises. They do not copy the exact pitch, cadence or even same words as the lead vocal.
An adlib is extra words or phrases that done fall directly into the harmony, timing and pitch of the main vocal.
Like a trumpet player going on a quick solo or fill.
Background vocals are harmonies and phrases that accent the main vocal. They aren’t meant to stand out. Like a group of singers on a chorus behind the lead vocalist.
They can be slightly different but shouldn’t be noticed much.
Sometimes a cleaner vocal fits the style of your track better than doubling adlibs do.
(Adlibs that explain the punchline are corny. Let the listener catch it. Don’t assume everybody’s slow. Leave some lyrics to be found years later when somebody listens to it for the 30th time and finally has an “ah ha” moment.)
But…there is no right or wrong way about it. Its all down to your personal taste.