Mastering is a form of audio post-production which is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device called a master recording
Tom Coyne (music engineer)
…Thomas J. Coyne (December 10, 1954 – April 12, 2017) was an American mastering engineer. Coyne was born in Elizabeth, New Jersey, and grew up in nearby Union, where he graduated from Roselle Catholic High School in 1972…
Magnetic tape was commonly used to create master copies.
Optimum Digital Levels with respect to the Full Digital Scale (dBFSD)
A common mastering processor for dynamic range compression
Mastering engineer Doug Sax with four disc cutting lathes