The mastering process is the final and most delicate step on the whole production.
Here we take a time to analyse the mixes to find the weakest spots and reinforce them.
If there are annoying frequencies, they are removed and some other will be boosted.
A multiband compression can be needed to achieve a complete enhancing of the whole mix.
The limiter and stereo width shall bring most of the final work and lift up the gain of the recording.