A mastering engineer's job is to look at the entirety of an audio recording and make sure it has a uniform style and sound before it goes into final production. The job typically requires a degree in audio, a studio with the proper acoustics, and a fair amount of sound editing software and hardware. Though often used as quality control for the final cut of a musical album, a mastering engineer is also part of the creation of movie soundtracks, voice recordings, and other forms of audio.
In order to be successful, a mastering engineer will need to be dedicated to reaching a high level of audio-editing mastery. He will need to study for many years to acquire this knowledge—many engineers have a degree in audio or acoustic engineering. There is a multitude of specific skills needed to shape a recording into a finished whole. The many aspects of a recorded track that will need to be edited include overall quality of sound, the addition or subtraction of certain sound elements, and the track arrangement.
For example, a major part of editing an audio track is making sure the final product can be played on many different kinds of devices without distortion. Certain instruments or vocals may be louder than others, bringing attention to different parts of a song than were intended. There may be clicks, pops, and other flaws in the recording. A mastering engineer cleans up these defects to reach an uniform sound where all elements of the track are at the same volume.
An audio engineer also is responsible for inserting sound effects and technical cuts that are impossible to put into a live recording. For instance, an audio engineer may cause one song to fade out or blend into another. They can also add sound effects, such as gunshots, which would be difficult to recreate in a studio setting.
Finally, an audio engineer is responsible for the final mix of tracks on a compact disc, or CD. They may change the order of songs, or cut some all together. In this way, they are much like the editor of a novel, changing the order of paragraphs in a story or cutting certain chapters to preserve brevity and theme.
A mastering engineer uses several kinds of equipment for his work. For example, a Real Time Analyzer (RTA) displays the spectrum frequencies of the different elements of an audio recording. Many kinds of software can be used to perform the same tasks, but some experts say the results are inferior to those achieved through using hardware. Another feature of a mastering engineer's arsenal is a studio with the proper acoustics.