How To EQ During Mastering
Sonically Transforming Your Mix Into The Final Master
In this blog post, I’m going to discuss how I sonically shape a mix during mastering. I’ll be diving into the EQing process itself but also how the rest of the mastering chain can affect the frequency balance. I hope you find a few tips that will enable you to improve the sound of your music.
Get In The Zone
Before I make a start on mastering, I like to get in the sonic zone. I listen to a brilliantly produced track with similar instrumentation to the song I’ll be mastering. This for me is a crucial step to achieve a successful final result. Skipping my warm up would be comparable to a footballer stepping onto the field without stretching; he won’t perform to the best of his ability!
Once my ears are in tune, I’ll begin listening critically to the track I’m mastering. I’m listening to hear what I do and don’t like about the track in its current state. My brain is searching for ideas on how to improve the sound. I believe it’s important to have an idea in my mind of where I want to take the track sonically, rather than just aimlessly changing the sound until I eventually find something that works.
Fix It In The Mix
A question to ask at the beginning of the session is: ‘Are there any issues with the mix that I CAN’T fix with mastering?’. What one can do with a single stereo file is very limited compared to stems. A problematic example would be If the vocal was sounding muffled but the hi-hat was sounding piercing in the same frequency range. An EQ boost might help the vocal but the hi-hat presence would also increase relatively. A quick alteration in the mix will be far more effective than trying to make the best out of a bad situation in the mastering.
Begin With The End In Mind
If I’m happy that I can get a great result from the mix, I’ll run it through my favourite mastering chain starting point. The chain starts out with very subtle settings that I will tweak and adjust to suit the needs of the track. I load my whole default chain rather than adding a plugin one by one because I believe the plugins interplay with each other to create the perfect final sound. If I focused just on the first EQ then added a compressor, the compressor might level out my EQ work and be a backwards step from what I was trying to do. I might also push some frequencies in the EQ only to find out that they become harsh when the limiter is added.
Here Is What My Chain Looks Like (unbranded)
Set The Level
My first step is to get the loudness of the track to around where I want it to be, this might be -9 integrated LUFS for a CD or -16 LUFS for streaming as specified in the AES guidelines for streaming loudness. You can read more about how I do this in this blog post. Once this is done I can proceed with shaping the track.
Now We’re Ready To Sonically Shape The Music
The first sound shaping tool in my mastering chain is the parametric EQ. It’s a surgical and transparent EQ that I use to manipulate the balance of the frequencies. Fab filter Pro Q2 is already loaded up in my chain in the natural phase setting (linear phase is not a higher quality setting sonically speaking, it’s just different). Below is a list of possible changes I would choose to make with the parametric EQ during mastering.
- Low Cut. If the track is feeling too bass heavy I might have a gentle cut anywhere up to 50Hz and a mild 6dB slope. A steep slope/high Q can phase the low end and even make it distort. The low cut will give me extra headroom to work with and tighten up the remaining bass.
- Low Mid Cut 150-350Hz. I’ll make this cut If the track is feeling boxy and needs a bit more clarity; as a mix often does.
- Playing With The Vocal (1kHz-5kHz). This is where I roll out the M/S (mid/side) processing. The lead vocal is almost always centred in the mix in mono. This means I can set the EQ band to ‘M’ meaning ‘mid/mono’ and make the boosts or cuts to get the vocal sitting perfectly.
- Reducing Stereo Low Frequencies (anything below 200Hz). Again, this is where M/S is put to use. Low frequencies wide in the stereo field can make a mix sound muddy and loose. I might engage a low shelf on the sides to tighten up the balance. (This might be a re-mix situation if the stereo low-end info is too much!)
There is a general ‘rule’ repeated by many mastering engineers that states that one shouldn't make boosts or cuts greater than 3dB. If you find yourself wanting to make these kinds of changes, then it’s more than likely that the track needs to be re-mixed. Another fact to consider is that a low-end boost has a secondary effect of dulling the high-end. Though the high frequencies haven't been reduced, the human ear perceives them as having less presence due to the increase in low frequencies. Another ‘rule’ is to keep the Q’s wide rather than pushing or cutting resonant frequencies. These ‘rules’ are a good starting point and more often than not I stick to them… but don’t be afraid to break the rules if it will have a positive effect on the music.
Shaping With Multi-band Compression
The multi-band compressor sits just after the parametric EQ in my chain and can have dramatic sonic shaping qualities on a master. For starters, the different bands can be boosted and cut in the same way as an EQ. The compression/expansion will also have an effect on the overall tonal balance. Below is a list of things to keep in mind when using a multi-band compressor to shape a master.
- Dynamic Phase is by far the most transparent setting and is, therefore, the most suitable for mastering.
- Compression will reduce the volume of the frequencies in a band. Compensate with a gain boost if you need to.
- Expansion will increase the volume of the frequencies in a band. Compensate with a gain reduction if you need to.
- The ratio of all the bands should be very similar. Aggressive compression in one band and light compression in another can lead to an unbalanced sound. The ratios should also be lower than 2:1, otherwise you’ll find yourself sucking the life out of the music.
At this point, my master is really starting to take its shape. Following the multi-band compressor, I’ll dive into the limiter, main compressor and exciter settings. These plugins are often the culprits for bringing about too much unwanted distortion. They also add the most volume to the master which also has an effect on the perceived balance. Louder music sounds fuller in the bass and more present in the high frequencies than a track with EXACTLY the same balance but a few decibels quieter. Getting the correct loudness of the master will help me balance the frequencies fairly against the reference tracks. The limiter and compressor can also have a flattening effect on the EQ curves of the parametric EQ and the tonal balance of the multi-band compressor. I’ll use my metering plugin to make sure the master is at the loudness I want it to be without compromising the dynamic range or true peak. Once I’ve set the limiter, compressor and exciter I might tweak the settings of the EQ and multi-band compressor to compensate any differences in frequency balance.
Adding Character With An Analogue Emulation EQ
In my workflow, this is the final stage of shaping the master. Everything else is in place and sounding great. I’ll head over to my analogue emulation EQ (usually the UAD Manley Massive Passive) and make a start on the final tweaks. For me, this stage is to enhance the character of the track. Below is a list of possible changes I would choose to make with the analogue emulation EQ during mastering.
- Low-end warmth can be achieved with a soft boost below 100Hz. I’m cautious to not overdo this as low end takes up a lot of headroom and can cause some distortion if too much is added at this point.
- A low-mid boost can add a touch of body to the track giving it a fuller sound. Again, caution is needed as too much of a boost in the 200-500Hz region will reduce clarity.
- High mid presence can bring out the vocals, add some attitude to the snare and give the track an overall sublet boost in clarity. If a track needs it, I’ll boost around 3-7kHz.
- Glistening top end sparkle is best achieved with an analogue EQ in my opinion. It can give high frequencies a really crisp feel without being overly crunchy or harsh.
The tools available to us mastering engineers are plentiful and powerful! The skill is having the musical discretion to know what to improve in the mix and what to leave as it is. The mastering process can be a journey of discovery into a completely revitalised mix. It can also a be a lesson in asserting self-control, not EQing for the sake of it and doing what’s best for the music.