The Mastering Chain
Mastering is often the final process of producing a record, after mixing the individual stems. By definition, it’s “the sculpting of an audio file so that it sounds it’s best on the widest variety of playback systems.”
To achieve this, a mastering chain of plugins all work in a specific order, performing subtle but concise enhancements with clear sonic goals.
This shouldn’t be used for correction but some anomalies could be made apparent during the chain. It’s advisable to fix these back in the stem mix.
An important step before you start: When rendering your final stem mix, make sure there are at least 6 decibels of headroom above the loudest peaks (meaning just turn down the master gain before exporting, until the peaks are at -6 db.)
Also always remove any effects, limiters and other dynamics processors from the master bus. You want to render a raw, clean and high quality stereo audio WAV or AIFF, exported at least 48 kHz sample rate and 24 bit audio.
Note: Insert an analyzer plugin like T-Racks Metering to read the audio and acoustic imaging as you make your edits, and to track the Master’s overall loudness.
Here are the plugins and settings I use for my mastering chain:
WAVES Renaissance EQ
Set a sharp High-Pass Filter at 20 Hz and Low-Pass Filter at 17-19 kHz.
The average adult can only hear frequencies up to about 17 kHz and feel sub bass frequencies to roughly 20 Hz, so there is no reason to have the ones outside of that range in your mix. Also, plugins still register them even though they’re imperceptible to us. Cutting them out allows the mastering chain to work only on the perceivable audio spectrum.
2. WAVES SSL G-Master Buss Compressor
Compression in mastering is used mainly to glue the track together to sound more cohesive. Don’t abuse this one though, too much compression will squeeze all the dynamics out of your mix.
Ratio – 4:1 (For every 4 decibels going in, 1 comes out)
Threshold – Start at around 8 db and adjust until you see anywhere from 1 to 3 db of attenuation. More than 3 db might be too much.
Attack/Release – I usually keep a faster attack at 3 ms and set the release to 0.3 ms.
3. T-Racks Quad Imaging
I choose to use multi-band imaging mainly because I like to keep the bass and sub bass frequencies in mono while adding width to the mids and highs.
This step is pretty simple. There aren’t too many controls to understand so just experiment with different imaging plugins and hear what works best for your sonic preferences and mix goals.
4. WAVES “Vitamin” Sonic Enhancer
This is where you could put an EQ like the T/Racks Linear Phase or SSL G-EQ, but I like the warmth and multi-band tone shaping capabilities of Vitamin. It has 5 bands and for mastering I generally give the LO and LO/MID a small boost for some thunder, along with the MID/HI and HI to polish the clarity, leaving the MID as it was.
At the bottom of each band control, you can even further adjust the imaging.
You can explore the other parameters for additional shaping for your track, just be sure there’s intent behind each edit.
5. WAVES Linear Phase Multi-Band Compressor
I slap this on after any EQ and Imaging to add color and balance across the spectrum. There is a factory preset I use as a template – Multi Electro Mastering. From there I make necessary adjustments based on my experience with audio and the specific goals for the track I’m mastering.
This plugin has a really dope feature. Once you add it to your chain, let the song play from start to finish. It will read the track and let you know the highest peak for each separate band in the audio.
Once it displays the exact peak values for you (in the picture above it’s the number displayed at the bottom of controls for each band, next to the “bypass” buttons: -16.9, -9.1, -14.5 ect.) Set the threshold for each band to match the number that is displayed.
For these next steps, switch the MAKEUP from “manual” to “auto”. You’ll find this on the right side under Trim and Dither. To the left of that, you’ll see a column of identical MASTER buttons with arrows pointing up/down, each controlling all 5 bands at once and corresponding with the Threshold, Gain, Range, Attack and Release.
Using the master adjustment buttons:
Range – The preset’s range starts a little too broad for me. Chisel it down to -8.0 for a more transparent effect.
Attack – The default value is 20.00 ms for the LOW band. I bring the master up until it’s around 40.00. The other 4 bands will have different cascading values as you make the adjustment. You can leave these alone or change them individually, up to you.
Threshold – Drop the Thresholds down until you see moderate activity with the yellow line in the main display. Focus on the LOW and L/MID. Since we switched the Makeup from manual to auto, the gain for all 5 bands will automatically increase as you bring the master threshold down.
Release – Slowly increase the master release time until you see the yellow line on the LOW and L/MID bands stabilize. I’ve found that a value of 1300 – 1500 works well for the 4 higher bands, then increasing the LOW a bit more to about 2000.
Once these steps are complete you should hear some color in the harmonics and a balanced spectrum. You can continue making adjustments to individual bands but try not to over do it.
6. T-Racks Classic Clipper
Now that you have the dynamics all dialed in, the spectrum is balanced and your mix is cohesive, it’s time to bring the volume up to commercial standards with this step and the next.
There are just 3 controls on this – Gain, Slope and Output.
I turn the slope all the way to the right for a sharp clip on the peaks only at the loudest sections of the song. I set the output to -3.0 db and slowly bring the gain up to around 6 or 7 db, until you see only about 0.5 db of clipping. Adding this plugin here will help prevent the limiter in the next step from working too hard.
7. T-Racks Brickwall Limiter
This step and the clipper before is why it’s important to leave that 6 db of headroom on the raw file. If you try to master a file that is already peaking at Zero (0.0), there won’t be much room for changes like rounding off the lows or chiseling the highs.
Any decibels above 0.0 will result in unwanted distortion and harsh vibes all around, so this brickwall limiter, with the help of that headroom and compression, will bring your polished and mastered audio up in volume so that it can compete with industry releases. Here are the settings I use to start..
Output Ceiling: -0.2 or -0.1
Release: About 40 ms
Attack: 2 ms
Style: Clean
Raise the input until you see around 1.5 to 2 db of gain reduction and the RMS Level is around -11.
Note: The “RMS” stands for Root/Mean/Square, and is the average loudness of a track. Most commercial songs are mastered to a loudness of between -12 to -9.
The ceiling and input are the only two that should be adhered to, but definitely experiment with the others!
At this point you should be hearing a sample of what your final master might sound like, ready to be rendered and prepped for release. This process is definitely more nuanced than this post, but you can use this info as a starting point. Experiment with different plugins, analyze your changes with a Metering plugin and always let your ears make the final decisions.
Also, compare every change with the original mix to be sure that the changes you’re making actually sound better. Ear fatigue can settle in and give the illusion of a positive adjustment.
It’s important to know though that if you have the budget, always send your songs out to a mastering engineer if you want them to sound their best. They have state of the art equipment, perfectly treated rooms, years of training, and a subjective set of ears for this specific purpose.
Otherwise, find your wave and ride it to the end of time.