Every now and again it’s good to take a look around the internet and see what others are putting together. MusicTech has put together an excellent article regarding the highly nuanced world of mastering sound post-production. As anyone that has dabbled with music production should know, it can be simple, subtle changes that take a great musical composition and transcend them into a special auditory experience.
The following are some excerpts from a wonderful article written by Adam Crute, a freelance engineer and media producer.
What is Mastering?
From the point of view of the songwriter/producer, mastering is perceived as a final stage of spit-and-polish that gives solidity and coherence to a mix, as well as being a process that balances and unifies the perceived volume and tonality of the individual components in an album – or montage, as we’ll be calling them – of recordings.
If you look at things from the perspective of a disc pressing plant, then mastering is the process of turning supplied audio content, often referred to as the pre-master, into a final glass (or wax) master disc from which CDs or vinyl records can be mass produced. By contrast, a film or television audio post-production engineer will have a very different take on things, seeing mastering as a process of creating correctly formatted output soundtracks that are required for distribution: mono, stereo, Dolby Digital 5.1, DTS Master HD and so-on. In generic terms, however, mastering can be thought of as preparing material for the next stage in the production process.
On Topping and Tailing:
Mastering is the place to define the start and end points of an audio file, by ‘topping and tailing’ excess noise or silence. Never trim audio right up to the moment sound starts and/or ends. Always leave around 50ms before the music starts, and apply a fade up across this span. If the music has an abrupt finish then do the same at the end, but leave a longer tail (100ms perhaps). If the music has a natural fade out, adjust this with your own fade, ending where you feel the track should end. Alternatively, to retain the natural fade, start a fade-out of up to 500ms starting at the point that the music is barely audible.
On Reading Waveforms:
The waveforms drawn by your DAW convey a lot of useful information for mastering. The solid core of the waveform indicates with the average, or RMS, signal level, whilst the spikes above and below the waveform show the peaks. Once you know this you can judge the music’s crest factor without separate metering. If the peaks extend a long way above the core of the waveform then you have a high crest factor, whereas peaks that only extend a short amount above the core would have a low crest factor. Waveforms where the peaks barely extend – if at all – are heavily compressed and limited.
Check out the whole articles on making the most of mastering.