Mastering is the final creative step in audio production. Simply put, creating the part (such as a CD-R master disc, or correctly encoded digital audio file) necessary for manufacturers or digital music distributors to make duplicates or replicas of the work.
 
Mastering allows the enhancement of your final mixes through the personal use of equalization, compression and other processes, so that the audio work will sound the best it possibly can, allowing more impact and emotion in the work.
 
A mastering engineer will pre-gap and create a flow between the tracks. Also, the engineer will limit all of the tacks in the work so that the listener does not have to increase or decrease the volume while listening to the work. Mastering allows your work to translate on to the widest range of playback systems.
 
Jay Frigoletto, a mastering engineer in Boston who’s credits include Black Eyed Peas, INXS, X-Men 2 soundtrack says: “Mastering is more than a fresh set of impartial ears, although this is certainly one advantage. It's the experience of the ears in mastering, which is different from mixing. The best mix engineers still get all of their work mastered.” He continues: “It is NOT simply putting an EQ and a limiter on the mix bus so your CD is loud and bright.”
 
John Scripp of Massive Mastering in Chicago explains: “A lot of people mistakenly think that mastering is all about ’making it really loud’. While the mastering phase is the ‘right time’ for such things, it's pretty low on the list of priorities. The first is to bring out the best qualities and minimize the worst qualities of the recordings.”
 
Every mastering engineer has his or her own sound. The best engineers ask for feedback and ask for examples of what you would like your work to sound like so they have something to compare your work to.  Every piece of music is unique and requires a specific approach to the mastering process.
 
Here’s a possible list of the steps involved in mastering:
 
1 Noise reduction
2 Compression to archive desired gain (loudness)
3 Stereo widening
4 Addition of harmonics
5 Smoothing out the frequency curve using a frequency analyzer and a parametric or passive graphic EQ
6 Limiting
 
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