Mastering can seem to some like an unknown black art, but, in reality it is just another part of audio production. Using a carful mix of compression, limiting, noise reduction and other processes, a track that has been mastered well can make it stand out from the crowd.

Here is a simple example of a mastered track;

Before

Here is the wave view before the track is mastered after having been mixed down. Notice how quiet but neat the wave body looks - this is perfect for mastering.

After

Now the track has been mastered. Notice how big the sound is, but that there is still room for the track to 'breathe'. This is becoming ever more important, as these days so many tracks are pushed to hard, volume wise, and you end up with a track that sounds over-compressed - or worse, distorted.