Explanation: It's tempting to think that mixing is the end of the process. Mastering can easily be overlooked, but it must not.
Even a good mix is not optimized for CD burning or radio play. As a simple experiment, rip the audio of your model song and open it in a wave editor. Then, open up the waveform of your song. You will most likely see that the model song looks somewhat like a block, while yours looks somewhat like a very craggy mountain range. That is because of mastering.
There are two areas you will focus on in mastering: Equalization and compression. Equalization will let to make final adjustments to your mix. You may need to boost the low frequencies, for example. Or, your mix may need more brilliance, so you will boost higher frequencies. Comparing to your model song will guide you.
Compression is keeping your volumes within a certain range. This is especially important for radio play, where a smooth level mix will sound better. As with the mixing process, be gentle and natural in your choice of compression.
Other things to do in mastering include normalizing and applying fades. Normalizing, done after compression, is the final stage in audio CD mastering. It brings the song up to the normal volume levels for CD burning. It analyzes the loudest part, and adjust the volume of the whole song accordingly. That's why you should compress first, because compression affects the levels of the song. Normalizing it should bring into its final level.
Fades include fading in at the beginning, and fading out at the end. You want to make sure that the moment before the music plays has true silence. You may choose to fade the music in, or have a quick fade right before the music starts so that any background noise and static on the track that precedes the music will not be heard. The same rule applies fade out at the end.
Some technicians will apply effects to an entire mix. One studio owner swore to me that putting a small amount of chorus will help any song. Others will cringe at that idea. Listen to your model song, experiment. It's all about getting a great sound.
Next 16. Burn the CD.