What the heck IS mastering, anyway?
I’m glad you asked…
Mastering is the final artistic and technical production step a record goes through before a song or album is sent to the manufacturing plant or distributed to the world of streaming.
Here’s an album… ready to see the world…
Mastering involves these five mandatory (in my opinion) steps which are done to the mixed two-track (stereo) material:
Cleaning up beginnings and endings of songs with edits and/or fades.
Establishing the spacing between tracks that feels good. Spaces are still important to those of us who consume albums. For folks who jump song to song on Spotify… not so much!
Balancing the relative levels between songs, so song A doesn’t feel loud or soft compared to song B or C… Generally this is based on the lead vocal or amount of midrange power, and is done by ear.
Generating the metadata information for artist, album and track titles, track start and ends, and, ideally, ISRC codes. It’s good practice to embed as this info in the manufactured cds, and to gather it together to supply to your aggregator (the company that will serve your files up to the on-line music world). I have never seen an aggregator actually use the metadata I’ve embedded in the files I’ve submitted to them, but I can generate a log that will at least supply to them the same info that is on the cd. ISRC (International Standard Recording Code) is a unique identifier for each piece of music that helps keep you (and the people who pay you) track of your work as it wanders around the interwebs. Visit http://www.usisrc.org for more info.
Preparing the “parts” for the cd plant and/or the aggregator. The plant gets a DDP fileset, a fairly bulletproof package of files that contains all the data needed to manufacture the physical discs. Aggregators all tend to want 16bit 44.1kHz wav files, so I supply those as well. I also make 320kbps MP3 files because those are the easiest to send to reviewers or share with folks via Dropbox or Google Drive. I’m happy to supply any files people need, FLACs, 24bit wav, and others are easy to generate, and if I have your cover art I’ll embed that in whatever files will take it.
The upper screenshot shows the tracks for an album loaded in, spaced, and leveled relative to each other. Yes, I do this work in Nuendo! In the lower image I have two different processing paths going on. Tracks 1, 2, 3, 6 and 7 sounded good with the same processing, but the other tracks needed a different approach. You can also see a little fade up on track six to help the transition between tracks five and six. This is pretty common and can make a huge difference when listening to the album in sequence.
Mastering can (and usually does) also involve some creative use of additional 2 track processing like compression, limiting, eq or a host of other processes. Removing extraneous noises, clicks, pops and the like are also things that are frequently done when mastering. If you can keep extraneous noises out of the mixes, so much the better. Sonic micro-mangement can also be done; raising and lowering or eq-ing sections of music, or even individual notes to get the best from a piece. Sometimes a little stereo adjustment can center up a track and make it feel more powerful, or add spaciousness to a track that wants to float just a little more. Sometimes a reverb tail can help the end of a song vanish into silence in the perfect way. Each song and album seems to ask for what it wants and my job is to know and trust my tools and ears enough that I can get out of the way and just help the music be what it seems to want to be.
The last audio step for every master is a VERY detailed listen using Izotope RX, where I can remove little anomalies that take me out of the music. An extremely powerful tool that can cause all kinds of damage or invisibly remove little glitches. I love this tool and even after a decade or more using it constantly I am still amazed at the magic it can do when directed properly!