EQing is one of the toughest concepts to grasp in mixing, so I’ll try to make it as simple as possible. The EQ can do a lot of different things. It can cut out low end for a less defined sound, it can cut out high end to make something sit more in the background, it can also do just about anything else in terms of blending sounds together.
There are 4 different approaches I tend to take with the EQ.
1 is the Creative approach. I use the creative approach when I’m looking to turn a sound into something a little different. This could mean cutting out all of the low end and boosting the highs to create something a little more novel in the background, like ear candy.
2 is the Spatial approach. I use the spatial approach when I’m trying to make space in a mix. Sometimes when there are a lot of sounds on top of one another, the mix can get cluttered. In order to make this listenable for the listener I will typically group all of the conflicting channels and add an EQ with a semi-wide frequency dip to lower the volume of the sounds containing the clutter. I will then take one of the sounds from that group, remove it from the group and place a counter boost over the same semi-wide frequency band, essentially boosting in the one sound what I removed in others. This enables that one sound within the cluttered group to stand out. It’s always nice to have a couple stand out elements instead of a bunch of fighting elements. We need contrast in our mixes in order to achieve clarity. The spatial approach helps us create space for the one or two sounds of our choosing. We could also create space by using filters (another type of EQ). Filters are high cut and low cut EQ’s essentially repackaged and sold as an additional product. The same can be done in an EQ. A filter can help us put a sound in the background by filtering out highs. Remove mud by filtering out lows. We can also add spatial movement by automating them.
3 is the Clean-up approach. For this approach we want to clean up the vocal. We can dip frequencies that we don’t like, we can boost frequencies we do like. As a typical rule of thumb, we should aim to decrease muddiness and always look to cut before boosting frequencies. If we start boosting frequencies recklessly our sound becomes unbalanced. Striving to achieve balance in your mixes is a top priority. Especially with vocals.
4 is the Balance approach. Balance is making a sound feel whole within a mix. If there is not enough low, people will say it sounds thin, if there is not enough high, people will say it sounds dull. Balance is the perfect sweet spot between the two. We want to make sure when finding balance we are doing it within the context of the mix, never on solo. This is because we are going to be listening to the mix altogether when it’s finished. Having balanced vocals is the first thing the listener will hear once the vocal comes into your song. The more cluttered your song is, the more room for error you may have with having an unbalanced vocal, the other aspects of the song can fill in the gaps. In rap/hiphop you typically have no room for error as the beats are typically minimal. Achieving balance can be relatively subjective. You can typically hear it when you hear it. When first starting out it will take some messing around with the EQ to figure out how to get that balanced fullness many radio songs have. Use your gut when analyzing and try suppressing EQ bands before boosting.
When mixing vocals, all of these techniques are important.
Unless we are doing something experimental, we will want lead vocals to sit in the center as the main prominent feature in our songs. Make sure the vocal is dominating the upper mid-range of the EQ spectrum. Typically adding a little high boost around this upper midrange can help the vocal “pop” a little more. I know I mentioned before cut before boosting. This is assuming your vocal is already balanced. We should aim to cut some of the low end completely out of the vocal to let the bass sit (under 80hz) and EQ dip some of the frequencies around 250hz if the frequencies sound like they’re conflicting with other aspects of the song.