EQ is without a doubt the most powerful tool you have in your arsenal. Understanding how to maximize this power is the key to gaining wider mixes and masters with lots of clarity. 1. Low Mid Clean Up
The most obvious spot to jump to when looking to get some clarity is in the low mids, typically around 250-500hz. In this region a lot of boxiness can creep up on a song and create a dull mix lacking any real definition. If I identify that there may be an issue in the lower mid region, the first thing I'm going to try is simply scooping out the offending area, often grabbing a slightly wider bell shape to bring this area down until I hear an improvement being careful not to go too far and lose some body to the music as well. The key is when using a somewhat wider bell centered in the low mid frequency range, you end up getting a slight cut in the bass region as well as the midrange region as well, which is sometimes a welcome addition. You may find that you now made things a little cleaner but lack a little bit of beef on the low end now. Doing a small boost before the cut can counter this, beefing up the low mids of the snare, extending down into the kick and bass, all while letting the low mid cut keep things from getting out of hand.
Example 1: Supplement a low mid cut for a small bass boost to regain some lost punch
2. The Midrange Shelf
A long time "secret weapon" if you will of mine has been to utilize almost a half tilt shelf in the form of a 2.5khz shelf. While this seems awfully drastic and low by most standard for a shelf, you do end up opening the midrange creating an explosion of clarity. This trick must be used with extreme care though as a lot of problem areas in the highs and upper mids can be deeply exposed for this, not making it well suited for everything. The shelf can end up extending gently down to around 700hz as well allowing vocals to come forward in a mix as well when this is needed
On few occasions I have used a 2.5khz shelf cut with a 5khz shelf boost. This ends up creating a curve that softens the 1-7khz range on material that is harsh around there, while also creating a very soft top end boost.
Example 2: a 2.5khz and 5khz shelf cut/boost for controlling harshness yet adding brightness
3. All about that Bass
Bass and Sub range can often be culprits to mixes that lack clarity and allow the music to move. Low end information eats up a lot of room in mixes and can also be a determining factor in how loud a song will end up being before distortion and negative artifacts become audible enough to take away from the song itself. Soloing your low end and determining what is useable info and just not mud robbing you of clarity is vital. There is also a delicate balance here of removing too much to make your tune thin as well. One thing I like to employee when needed is low end shelving over using HPF, often in M/S (Mid Side). I also will sometimes go for a "resonant bump" at times too, raising the amplitude right before shelving down, creating a bit more punch while thinning out potential mud and rumble. In some mixes the side channels can also have excessive low sub info and depending on the genre and mix itself, may not be a welcome addition (use discretion here). Gently sloping the sides down is a good way to alleviate some of this without using a hard cut of a HPF.
Example 3: Low end shelves to clean up rumble
This concludes 3 Eq tricks in mastering for mix clarity and hopefully helps bring you closer to better mixes as well as shedding some light into some mastering scenarios and fixes that can be used. Be sure to subscribe as well as reach out for you mastering needs!