When releasing a vinyl record, the mastering engineer cuts grooves in a disc called a lacquer. Metal stampers are made as a reverse of the lacquer. In other words, the stampers have ridges instead of grooves in order to “press" record copies. How many lacquers are created and how many steps are taken in the process depends on how many records are going to be pressed. Mastering engineers became known for their ability to make final enhancements to the music mixes, while also executing the technical requirements.
Nowadays, the majority of mastering engineers will probably never cut a lacquer for vinyl record pressing. Instead, their craft lies in mastering for digital release formats. They are expected to elevate the quality of the mixes and make sure the technical requirements of the format are met. If the mixes have too much low end (low frequencies), the mastering engineer may clean them up a bit, or he may add stereo processing to create more depth. Finally, in an area that has drawn controversy, the mastering engineer makes the final product sound as loud as other modern day commercial releases. Some say the loudness issue has gone too far, resulting in “loudness wars" that sacrifice the integrity of the music.
Mastering is the final stage of music production. Afterwards, the finished “master" is ready to be manufactured, configured for downloads, or utilized for its intended use.
(Image courtesy WikiCommons, Masterplus)