Audio Mastering basic overview

What is Mastering?
Mastering is the final step in the creation of an album before duplication. Mastering is all about the big picture, how the collection of songs works together as an album, and getting the album to sound good on most systems, from HI-FIs to iPods. Mixing is taking a bunch of tracks and making it sound great, Mastering is taking those great mixes and making them even better. It’s the final step of sonic correction and sonic enhancement.

It’s just about loudness right?
There’s a misconception that mastering is just about making a recording loud, that’s just one of the processes involved. Compression, Equalization, Harmonic Exciting and Stereo Widening are often part of the mastering process as well.

Mastering at home
Before you attempt to master at home there are a few requirements.

• Room treatment – If you haven’t take the effort to get your studio sounding as good as it can acoustically you can can't completely trust what you're hearing.
• Monitors – as important as having a great sounding room, you need accurate monitors, you can not master on computer speakers or headphones.
• Experience – Complete understanding of your tools is essential, if you aren’t 200% sure how to properly use a multi-band harmonic exciter, it might be better to leave this to a professional.

Watch out!
Most professionals agree, Mastering your own music is a bad idea. It’s very common for bands to record and mix themselves then send the mixes to a mastering engineer. Why? Partly because of the requirements of mastering, but more because of the emotional attachment you have to your own music. When you’ve just spent a few months recording and mixing, you lose perspective, you can’t see the forest for the trees. If you must master your own music, don’t listen to the songs for few days or weeks, hopefully you will have a different perspective when you do finally listen again. And hopefully you won’t want to go back and remix it all over again.

Seriously, just tell me how.
OK, now with all those warnings out of the way, here is a general strategy and workflow for mastering music.

1. Import files - Your stereo mixdown of each song should be at the same  format as the original files. If you recorded at 24 bit and 48kHz, you export your mix at 24/48k. Bring all the files into a new session with the same settings as the files (24/48).
2. References - It's a good idea to bring in a few other high quality audio mastered songs in a similar style as a target for the sound you're trying to achieve. You can also choose different styles and focus on different aspects, the low end of song A, the brightness of song B, the width of song C etc. Each reference file goes on a separate track and routed so they will not be going to your effects chain, go directly to your interface outputs if possible.
3. Limiting - A brickwall limiter will bring up the level to the modern production standard, depending on how hard it's working your mix balances will change. This is something to be aware of and why I recommend having the limiter on fairly early in the mastering process. Start with a fairly conservative level.
4. EQ - Insert a high quality EQ plugin before the limiter.Start with really gentle settings for sweetening the sound: -1dB at 300Hz; +1dB at 5kHz on the high shelf. If you have a few songs to master in this project I recommend having an EQ for each song to correct problems and even out the frequency balances between songs.
5. Mix bus compression - You may need to use some compression to get the elements of the mix to 'glue' a little better if there's too much separation between instruments. A stereo compressor pushing back a little all the time is a great way to achieve that. Moderate attack and release and a few dB of gain reduction will help smooth things out before hitting the limiter.
6. Fades and sequencing - This is a good time to check the beginnings and ends of each song and make sure they fade in nicely and there's no noise or excess time. If you have multiple songs in the project check that each song flows well into the next, try different song orders etc.
7. Next steps - If you haven't taken a break yet, take a some time to rest your ears. When you come back you should intuitively know what's still a problem and if not leave it alone. It's easy to go to far with mastering.
8. Exporting - If there is a Dither option in the limiter, switch it on. Render/bounce your mastered song with the highest quality settings

 Hopefully this article has been useful to you, if you have any comments or questions about the tools or techniques please leave a comment.