These are all things that are sometimes introduced through the recording, production and mixing stages when making a record but are unwanted on the final release.

How do these things come about?

They can sprout from a number of areas during the record making process;

  • Prominent room modes in a recording space

  • Positioning and selection of microphones

  • Monitoring environment and the decisions that result during the mixing process.

But most commonly during the recording and production stages tracks are pieced together with a creative mind set, so often technical things like resonances in a room that may build up on a recording are overlooked. This is very forgivable as creative and unique recordings are the aim of the game. When producing, dividing attention between the technicalities and the creative task at hand can sometimes hinder the musical quality of the production.

This is why in mastering, the rooms accuracy and the two auditory organs on the side of an engineers head play a very important role to clean and polish the final product.

A practice commonly employed during a mastering session is corrective equalisation (sometimes referred to as surgical EQ). A dry explanation is that with a parametric or dynamic equaliser, a narrow bandwidth (high Q value) with a bell shape is placed over a ringing frequency and is attenuated.

Before commencing to look at how I approach corrective EQ it is always important to know that these are processes that I have developed and work for me. Everybody is different, and it is important when learning and exploring these tools to know that there are no rules, as long as you get results. I strongly encourage anyone whether they’re mixing, tracking, producing or just mucking around in their DAW to work freely and explore different styles of EQ, different applications and methods to find something that you feel comfortable with. By developing your own workflow you feel comfortable with, your creativity and results will improve ten-fold.

However this post is more intended to discuss and show you a little more on how I approach this task. Enjoy.

In my working process, corrective EQ is applied for a few reasons;

1) No masters should ever be released with unintended ringing, resonances, humming, muddy low end or sibilance distracting a listener from the musical content.

2) Ringing and resonant frequencies can sometimes trigger the gain-reduction on compressors instead of the instruments transients, making the compression work against the music. By dipping these frequencies it allows me to produce more dynamic and loud masters without the mixes feel like they're being overworked by compression.

3) The most subtle of corrections can begin to open up a mix clearing up surrounding elements.

4) At times can create some definition and separation between the bass and kick drum when needed.

I only approach this process with a digital equaliser. Why? Because the digital realm facilitates much more accurate and narrow bandwidths commonly not found with analog equipment. Additionally, the switched/stepped potentiometers on my analog equipment don’t offer me variable control over the frequency band I’m dipping. The frequency points on my analog equipment are pre-determined. This is why all my corrective EQ is done digitally.

2 notches dealing with some ringing in a floor tom and woofy tones from a bass guitar.

Moving onto the actual application of equalising. In the chain, I typically sit two corrective EQs; one before my D-A conversion before it is compressed in the analog realm and another straight after my A-D conversion before it gets digitally compressed and limited. The reason for the two is I only ever attenuate a little bit off each equaliser at a time and I don’t want to start effecting the tone of other instruments that share that same space by taking out a big chunk with a single EQ dipping 3db or more. This is very important because this is surgical, not creative. My goal is just to get rid of unwanted ringing or other noises and not begin to alter the tone of corresponding instruments in the given frequency range. When getting into the nitty gritty of a mix I make sure that nothing i'm doing surgically is effecting the intentions and tone of the mix.

Furthermore, all the corrective work is going on before it gets compressed in the analog domain as well as before it is limited in the digital domain. This is for the reason previously stated, that I don’t want ringing/resonances effecting the compressors/limiters.

Digital equalisers I use for corrective/surgical purposes:
- Brainworx hybrid
- Brainworx dyn-EQ
- Brainworx digital-V2
- FabFilter pro-Q

This is an overview on one way I employ corrective EQ and why it is an important part of my process. There are a lot of other techniques and methods in how I work with corrective equalisation in mind when mastering, but I wanted to keep this post as short to the point as possible, and I am intending to write more on the topic in the future.

In my next instalment, I’ll be discussing creative equalisation, techniques and its role in the mastering process.