Using Equalization in Mixing
I find a lot of times equalization in combination with dynamics control and saturation can be used to sweeten a mix, and mixing is many times simply a matter of make things fit together nicely with Equalization.
Equalization or EQ is often thought of in a subtractive sense in the mix, and its usually about more cutting than boosting. That’s because, a lot of high pass filtering typically is used to clean up the low end of channels, so that the instruments with a lot of low end like kick drum and bass frequencies can really come through un garbled and clean, because they are not being combined with a lot of low frequency garbage from things like the vocals, guitar, or snare drum.
Common EQ problems can be anything from too much mid range in drums to excess sibilance and high end in the vocals . What sounds good for one type of music, might sound kind of dumb in another mix. There are infinite choices of frequencies, and infinite ways to boost or cut them. Its a matter of taste and feel and experience. But more on that later.
High Pass is your Friend
High pass filtering can start at any where from 80 or 100, to 120 Hz or so on most analog mixing boards. On digital systems its often anything you want, and you can control the slope and see a graphic representation of the sound. Look for one main low frequency (the resonant frequency) to pop up as a large hill in the low end. Just below that you can usually see a bunch of garbage that can be cut to make the sound cleaner. Experiment with high pass filtering to determine what sounds nice. You can get drastic with it and high pass well up into the 250Hz-500Hz mid-range sort of frequencies on things like high hat or tambourine (tambourine will often have nothing below 5k or so). Crazy!
Too much high pass filtering and your sound is going to sound thin. Like a tinny sort of tin can noise. A thin atmospheric high frequency top with no beef no meat down at the bottom.
High pass filtering when used properly can clear up vocals and bring a sense of clarity and separation to the mix. By saving the low end for tracks with more bass, we can make the mix seem more natural sounding and blend together nicely.
High passing the guitars a bit in a mix can leave more room for bass to live down in the bottom. High passing snare drum can leave more room for the kick to live in the bottom of the drum kit sound, and so forth.
Sometimes the vocals will have some pops in the low frequencies if an insufficient amount of windscreen or pop filter was used. This can be “dumped” off the low end to make the vocals sound more even. If the compressor is pumping….. its probably from low end frequencies… So dumping them may yield a more natural compression response.
Mid range frequencies are either boosted or cut with a sweep able frequency band, and a Q control( on parametric EQs) and a gain knob to either boost or cut the selected frequency. Q control is the narrowness, or the wideness of the affected frequency band. A tight Q is a narrow spike, and a wide Q is more of a rounded hill shape. By adjusting the frequency and Q control you can reduce or boost different frequency bands in the mid range frequencies. A tight spike can be used to pull out a weird ringing in the snare, or a wide boost can fatten a thin sounding vocal. Be careful with very narrow or sharp boosts. A 3 or 4 db boost is a small boost. 10 or 15db cut or boost is usually crazyland but I mean don’t be afraid to get crazy with it sometimes and experiment. Sometimes a huge cut can provide a stark contrast, but usually subtle moves are best at first. It’s a matter of taste. Too much scooping in the mids can make a vocal sound unnatural. Eventually you’ll hear what you want to boost or cut, and begin to search around for the right frequency by rolling the frequency around to find right where the “bad” sound is or where to boost. A common technique is to tighten the Q a bit and slowly sweep the frequency of the EQ until you find the one you are hearing, then either cut, or boost it up or down with the gain.
Low pass and High end boosts mess with the upper frequency ranges of the sound. Up there at the top is where the tambourine lives… oh Yeah you betcha. and the high hat too. Also up there is where you hear the SSSSSes and the Ts the SSSSibilenCCCCCeee of words and the contestantS of wordSS. Too little and your vocals will sound muffled and underwater … too much and they will sound harsh and piercing. Sometimes the very top is referred to as the “air” band. The very tippy top by 10k and 12k and above. This is the airy heavenly frequencies that thou shalt not boost too much or yer mix is gonna sound like nails on a chalkboard on a bright system. Get a bright pair of speakers and test your sounds out on them. The human ear naturally adapts to high frequency punishment. Ever get “concert head” from a loud concert and step out side to realize you’re practically deaf? Sometimes mixes with too much high end are called “cocaine bright” cause in the 80s when they were putting all the shit up their noses for fun, their ears would get really worn out because the loud bright speakers that were popular at the time and engineers strove for more sparkly shiney airy mixes until disco fever melted a hot hot fire on the dance floor and everyone screamed “Party” and then George HW Bush was president then all the sudden Bill Clinton was president and well … the 80s were over… and we moved on stylistically. So the moral of the story is check your mixes for too much high frequency stuff, or boost away and don’t get too crazy you party animals!
Multi Band Compressors
A multi band compressor is useful for taming the sharp piercing frequencies of vocals or drums. This is also sometimes called de-essing. By smashing the high frequencies down with a frequency dependent compressor, we let the lows escape unscathed, and reduce the sharp stabbing frequencies up top.
The high frequencies are where the human ear most hears “loudness” around 5k our so are usually the most piercing and loud frequencies. Sometimes its useful to boost around 2.5k or 5k to give more high frequency “presence” This is the biting highs that help an electric guitar bite through the mix, or the snap that the snare or high hat might have.
Usually the drums are sort of scooped in the middle for many modern types of music. Knowing when to scoop and when to not pull the mid range out, and how much, and where, is a big part of mixing drums. Although there’s no “right” way to do it, there are several common types of sounds that can be achieved. Listen to some reference material from the genre you are working. Ask the band what their influences are, and who they are into. Sometimes we cant make you into your favorite band, but maybe we can get close, or make choices that are similar to the mix choices in their music.
Kick drums vary from flat and midrangey, to booming and bold. When you think midrangey kick drum think Beatles kick drum sound. Its sort of boxy and not as low as a “modern” kick drum sound. A good key that you’re dealing with this type of kick is that there isn’t anything below 100hz. Don’t sweat it! Your mix can have that classic 60s sound, or that punchy 70s feel to it. Cool!
On the other side of the spectrum you have the massive low end frequency explosion of a modern kick, that’s meant to rock the house. This is meant to deliver an explosion of heart stopping bass in the sub 100hz range. So you can go boost crazy…..well almost. Make sure you listen to your mixes on a sub-woofer system with decent power to see if the low end is out of control. It might sound dope….but some kid with a 1000 watt stereo in his car’s head is going to explode and its gonna sound like garbage. But tighten that shit up with a multi band ex-pander in the low end and use to compression to tame back the wild sub busting earth quaking frequencies to reasonable level and it will sound real nice oh yeah!
On the top end of the kick there is the attack, which is anywhere from 1.5k to say 5k or 10k on the top end. This is the snapping initial spike you hear and can see in a waveform of a kick drum. How much attack and where is a matter of taste. Some metal music has tons of high frequency “ice pick” frequencies to punish the listener with snapping highs. You can use a multi band expander to suck down the crap you don’t like that is keeping the sound from being clear and transparent attack.
Some types of music don’t even have realistic kick drum sounds. 808s and other types of synth kicks are commonplace. Each has its own character. Whats important is to have a decent listening room where you can hear if the bass is too much, see if the top end is cutting, or is too piercing, and remember its all a matter of taste and there are no rules.
Mixing snare drum is usually about pulling crappy mid range frequencies. A lot of albums have been made with a Shure SM57 on Snare, but love it or hate it, most drums usually have a boxy mid range that can be pulled. Listen to the mix and identify a place between the main fundamental low end, and the top cracking attack of the snare and pull a wide mid-range scoop out of it. A reduction around 500hz is sometimes nice. 250hz pull can be nice too. oh Geez let me tell you 400 hz can be a nice one to pull out of drums too. Try it out and see what you think!
Most drums have a ring to them unless they’re really dead sounding. Sometimes a bad ringing in the snare drum can be irritating in the mix, so you can cut it a bit with a sharp pull and sweep it around until you find the offending ring.
Another common technique is to boost the low end fundamental “mountain” you can see at the bottom on a graphic analyzer of the sound. This will give the snare an amount of low end punch in the mix.
Sometimes a sloppy snare can be cleaned up with a little bit of high frequency expansion. Or a slight boost in the high end to give it crack and attack. A lot will depend on how the drum was tuned and what type of drum heads were used, as well as the drum and dampening of the head. Snare drums vary from dry and flat to ringy and with many harmonics that are ringing everywhere all over. Sometimes a piece of tape or cloth or similar dampening material is placed on the drum to tighten up the ringing. Cool!
High hat and toms are often next. With high hat occupying the upper registers and toms ringing out in mid range somewhere. Again, its a matter of taste. Mid range cuts and fundamental low end boosts, or high frequency attack boosts are common. Play with the EQ in the mix and find what works best for the kit you’re recording and determine how to craft a nice blend of elements together in a pleasing way.
Overheads room Mics
Overheads and Room mic capture the room ambiance and Cymbals and the echo of the drums in the room. Overheads are commonly high passed to varying degrees, and room mics add a “slop” room-rock type ambiance to the sound. Don’t be afraid to completely ditch the room mics or overheads or Hat mic or whatever if some elements just aren’t necessary in the mix. Some mixes lend themselves to the main drum sound from the overheads, and more of the body from the close mics, or maybe more of a room tone, or a tight modern sound. Feel out different options and explore whats the best decision and talk about it. Different people like different things… and that’s ok.. its music, not an absolute correct way or wrong answer, like in math or science. Its human expression and you can do it however you want!
Guitar and Bass
Guitar and Bass are often the widest frequency bands in a mix. An electric guitar often produces a wall of sound between 100Hz and 8k or so which can be high passed or low passed what ever suits the MIX best. All guitar and bass sounds are greatly dependent on the instruments and equipment used to produce them, so to a certain extent, it is what it is. You’re not going to EQ a guitar or bass sound into something totally different than what it was and have no weirdness going on, it can only be what it is… so get it right sounding out of the amp, get it right sounding out of the speakers when tracking, and tweak it in the mix to get it right sounding for the songs you’re doing.
Some guitars lend themselves to harsh push up at the top for a lot of grating abrasive crunch and distortion. Its important that not too much is boosted up there, or it could sound harsh or unbalanced. Other times Bass guitar will have a broad rich mid-range. Adding distortion or saturation to these can fatten or thicken the middle for a juicier tone.
Sometimes contrasting tones are useful. For example you could have a harsh attack from a kick inside mic, and a fat bottom of a kick outside mic. Blended together, awesome. When samples are overlay-ed drums, a fat sample, or a snapping attack can be simultaneously blended in an artistic way way make a cool result.
Frequency masking is where one frequency covers up something in the same frequency range. A good example is too loud guitars. Imagine a loud bar scene. The rock star guitar player turns his amp up to 11 and rocks out. The loud guitars wipe out the vocals and everyone complains. The poor grumpy sound guy is pulling his hair out trying to get the vocals louder and louder to no avail because the strong guitar frequency masking the vocal. On a smaller scale, synthesizer or cymbal sounds can wash out other sounds. Cutting or pulling down those frequencies will tend to open up the mix and make things cleaner and more focused. By choosing contrasting bright and dark, distant and close sounds, an interesting combination of sounds can be made. An exciting mix blends the different elements together into a one of a kind sonic picture with each element having effective impact in the mix.
Sometimes EQ can be used as an effect to make a section sound like a megaphone or a thin whisper sound, or underwater drum sound at the beginning of a song. The possibilities are endless.
EQ for Artistic Effect
Making the stylistic decisions and determining what the right frequency balance and sound is good for each element can be boggling at first but don’t be too worried. There’s nothing wrong with leaving an EQ flat for a sound that is OK as is, and you don’t have to EQ mix the same. Doing whats necessary for your own satisfaction with the mix, the clients satisfaction, and ultimately the listeners satisfaction are all important, and finding a balance between those different opinions and preferences is going to be different for every project.. So lets talk about it, and when you’re making stylistic EQ decisions at any stage, try out different things, and don’t be afraid to undo something you don’t like that you did and either do nothing, or do something a little differently.