Choosing equalizer and compression plug-ins for mastering is a matter of personal taste. Think about how you want your finished recording to sound. Do you want it to be warm or glossy? Do you want it to be louder than other recordings? Use these criteria in tandem with past recording experience to select which plug-ins to use. It's a safe bet to select an EQ with at least five frequency bands and a good multiband compressor with at least four frequency bands. These allow you to isolate and alter specific musical frequencies without affecting other frequency levels in the mix.
Using a pair of monitors and your computer, open your digital audio workstation and listen to the final mix you're going to master. Does the guitar have too much high end? Are the drums too loud? Do the vocals change volume from verse to chorus? Write down all of your observations. Using the same pair of monitors, listen to a track by one of your favorite artists. Pay close attention to how the instruments and vocals sounds, and think about how to achieve those same results using EQ and compression. Listening to a track you enjoy often spurs ideas for correcting your own tracks.
Using the new track function of your recording program, create a master track within your final mix. Now place your EQ in the top-most insert slot of the master track. Underneath it, place your multiband compression plug-in. Play the song to make sure the mix is traveling through the master track. If it is not, make sure your inputs and outputs are routed correctly.
Using your observations from Step 2, apply EQ and multiband compression to your final mix. You shouldn't have to apply a lot of either effect. If you do, return to your final mix and adjust the EQ or dynamics instrument by instrument. Overcompensating for a poor mix in the mastering phase often muddies, rather than clarifies, a recording. If you're having trouble achieving a desired sound, try using the factory presets created by a plug-in's manufacturer. These presets give you clues for operating a mastering plug-in more effectively.
To create a mastered audio file, render the file to your hard drive using the bounce function within your DAW. You can also send your DAW's output channels to a CD, tape or DAT recorder to create a physical copy. You're now ready to present your finished recording to the public.