Automation in Mastering: Volume and Beyond
Friday December 30, 2016. 04:57 PM , from Audiotuts+
In this tutorial I'll show you how to enhance completed mixes through applying various automation techniques when mastering. I'll look at the potential pros and cons of the techniques and why you might want to employ one technique over another.Automation can be described as movement of a parameter, for example, a fader during the music. These movements can be programmed (step time) or performed (real-time). The workstation has the ability to recall these movements on playback.Automating VolumeVolume changes to an overall mix can help add more energy and excitement to a track. These changes can be gradual or sudden. A sudden increase can help uplift a chorus whilst a gradual change can intensify a build up.Before I look at automating volume it’s important to understand how you measure it. Below are two ways of calculating it—peak and RMS.Peak volume: How far the measurement is away or over the celling (0.0dB)RMS: The average volume over a window of timeThe brain normally uses the RMS, or root mean square, value in judging how loud it perceives the music to be. The average volume can be controlled from a parameter called threshold/gain which is common to a limiter. Increasing the RMS value will make it sound louder but at a cost of a lesser dynamic range.Try uplifting the chorus sections of a piece of music by making the chorus a little louder then the verses. Be subtle as to not lose too much of the dynamic as discussed in the previous paragraph. I don't normally automate the threshold more then 1dB to 1.5dB.Bridge sections often work well for the opposite, reducing the threshold to the extent that no peak reduction is occurring. This results in giving the chorus section an even bigger impression.Automating Peak VolumeAutomating the peak volume is often used for fades. You can automate the peak volume from a fader.For fades, the limiter needs to be pre-fader. If your fading you need to control the limiter, rather then fader controlling the effect it has on the limiter. For example, if the limiter was post-fader, and you pulled down the volume on the fader, the amount of volume going into the limiter would decrease. The limiter would come to a point where it’s not attenuating, because now it has no peaks to reduce. This would result in a less consistent dynamic range on the fade out.Stereo Width AutomationAutomating the stereo width of a song can make a section feel more epic. However, too much stereo widening during mastering can cause phasing, resulting in a thinner sound.Try automating the stereo width by attenuating the sides for a verse (pic 1) and boosting for a chorus (pic 2). This will give an increased sense of width with a reduced risk of phasing.As a general rule I don't boost the sides more then 0.5db. Another tip is to use a tool that gives you control over the stereo width of a band rather then the entire frequency range. This will help retain a more stable master.Verse: 0.5db cut in the high midsChorus: 0.5db boost in the high midsAutomating a CompressorIt’s not usual to automate a compressor in mastering, in particular the attack time, helping to create variety and movement within a master.Changing to a slower attack time for a chorus often works well in making the section sound more upfront, resulting in a more three-dimensional master.Automation in Noise RestorationRestoration is the process of removing artefacts like hiss, crackle and hum from the audio. It’s often better to remove artefacts before mastering, creating a better starting point which to work with.Noise is the result of a poor signal to noise ratio most evident during its quieter parts, for example, the start and end of the audio.The problem with restoration tools is that they are not intelligent enough to focus on the noise only, often removing fundamental frequencies in the more busy sections of music.With this in mind, automating a restoration plug-in to engage only on the more sparse sections—as noise is only a problem if you can hear it—can be a better option in retaining the quality of the audio throughout.Automating a De-EsserA de-esser’s main role is to reduce vocal sibilance, syllables like the harshness of words beginning with S and T, often living in the upper mid-range. A de-esser, however, can’t recognise the difference between a harsh S or T and that of a hash high-hat for example.Again, engaging the plug-in only when the sibilance occurs will help retain the quality of the audio.Automating ReverbUsing reverb in mastering is most often used in a corrective process rather then a creative.Occasions arise when a mastering engineer receives a track with the tail end subjectively cut too short. This is where automated reverb can help.Automating the reverb from dry to wet in time with the fade can help smooth or prolong the fade, giving a more professional master.ConclusionIn this tutorial I looked at automating the loudness, width and depth to help create a more exciting, epic and three-dimensional master. In addition, I covered corrective automation whilst helping to perverse the quality of the audio.Some or all of the techniques discussed can be applied to a single master.