
Once mastering engineers have completed their work, they transfer the audio tracks to a data storage device-the master, the source from which all duplicate copies will be made. The mastering process involves listening critically to the album or track through state-of-the-art monitors in an acoustically pristine room, followed by adjusting the sound in a variety of incremental ways: using compression, equalization, and other tools to make the recording sound more vibrant, more visceral, more musical-however that may be defined by the producer or artist. The work of a mastering engineer requires extensive training and practice in record production, audio technology, and-critically-the ear, a mastering engineer’s most valuable tool.

Broadly speaking, the mastering engineer ’s task is to ensure that an album is sonically cohesive and impactful, and that it will play well in any format and through any medium: as a 140-gram vinyl, digital mp3, CD, or internet stream and played through earbuds, laptop speakers, loudspeakers in a shopping mall, or movie theater surround sound. Mastering is an often misunderstood and crucial process in the life cycle of a recording or album, the final creative step before release when its overall dynamic and spectral balance is sculpted and polished.
