Mastering is often seen as a dark and mysterious art. This is particularly true among junior producers and engineers who want to learn how do do it themselves. There’s a lot of different advice floating around these internets, some of it conflicting. It can be difficult to know if you’re taking the right approach. It can be difficult to know how you can improve.
Short of hiring a teacher or mentor, the best thing to do is be clear about what you’re trying to achieve. And that means understanding the purpose of mastering.
I’ve written quite a lot about mastering here on this blog. Put simply mastering is the process that takes a stereo mixdown that sounds great in the studio and turns it into a stereo audio file that’s appropriate for distribution.
So the question is: how do you know if a stereo audio file is appropriate for distribution?
I approach this in two parts: characteristics of the audio and characteristics of the format.
For the audio to be appropriate for distribution, the two primary factors to consider are tone and level. Fortunately it’s fairly easy to know what to aim for – simply listen to other commercial recordings (in your acoustically treated, calibrated monitoring environment). To adjust your mixdown so that the audio is more appropriate for distribution, your principle tools will be a good equaliser for adjusting tone and a good limiter for controlling crest factor (which gives you freedom in adjusting level).
For the format to be appropriate for distribution, you need to know what how the release will be distributed. For CD duplication, you’ll probably need to author a master disc. For replication, you might need a DDP image. For online distribution, a linear CD-resolution audio file might be sufficient. Or a higher-than-CD-resolution file might be more appropriate. To create these formats you’ll need appropriate authoring tools. Professional CD authoring software is probably necessary if you want to master for CD. For online distribution, a render from your audio software (at the correct resolution and format) might be sufficient. Apple’s mastering tools for their ‘Mastered For iTunes’ program might also be relevant to your interests.