Targeting your efforts
As promised, we’ve provided a breakdown of the frequency spectrum to help you get your head around which sounds live where. If you’re ever stumped, this guide can help you drill down to the offending (or lean) frequency to help you make a more effective adjustment. Below are guidelines, not steadfast rules, and your own auditory input is what makes this process all the more personal and enjoyable. And that’s really the point: Have fun!
Sub-bass: 20Hz to 50Hz
While humans can technically hear down to the depths of this register, most of these frequencies are less cerebral and more gut. Somewhere in the middle of this register is where your subwoofer will make that eerie sound of deep space in sci-fi movies, and these frequencies can add some serious, unearthly power. However, you would very rarely want to add more of this sound, and taking away from here can help give the music more overall clarity.
Bass: 50Hz to 200Hz
The majority of the time, a stalwart hip-hop groove will start at or around 60Hz. The foundational, big-hitting lower register that spouts forth from your subwoofer rests in this domain, including the heavy punch of the kick drum, and even lower tom drums and bass guitar. Moving up toward the 200Hz line begins to affect the very lowest boom of acoustic guitars, piano, vocals, lower brass, and strings. If the music is too darn heavy, or not heavy enough down low, a bit of an adjustment here will help.
Upper bass to lower midrange: 200Hz to 800Hz
Rising above 200Hz starts to deal with the lighter side of the low end. This region is where the meatier body of an instrument hangs out. Adding EQ volume around the middle of this spectrum can add a bit of oomph to richer tones, including the lower end of vocals, deeper notes from synthesizers, low brass and piano, and some of the golden tones from the bottom of an acoustic guitar. Lowering the level a bit here can clear up some space, and open up the sound. Moving to the 800Hz region, you’ll start to affect the body of instruments, lending more weight with addition, or lightening the load with subtraction.
Midrange: 800Hz to 2kHz
This area is a touchy one that can change the sound quickly. Putting on the brakes in this region can take away the brittle sound of instruments. Adding some juice, especially toward the top end, can give things a metallic touch, and can wear down your ears quickly if pushed.
Upper mids: 2kHz to 4kHz
As mentioned above, this register is where your ears aim a lot of their focus. Adding or subtracting here can raise or lower the snap of higher instrumentation quickly. Sounds like the pop of snare, and the brash blare of a trumpet can all be affected here. Adding a little push here can give more clarity to vocal consonances, as well as acoustic and electric guitar and piano.
Presence/sibilance register: 4kHz to 7kHz
This is commonly referred to as the presence zone and leads into the highest range of pitches produced by most natural instruments. Boosting the lower end of this scale can make the music sound more forward, as if pushed a little closer to your ears. Backing it off can open the sound and push instruments away for more depth. The upper end of this region is also responsible for the sharp hissing “s” of vocals, known as sibilance. If sharp consonants are popping out at you like the bite of a snake, cutting a few dB from around 5kHz to 7kHz can solve the issue, and save you some pain and suffering.
Brilliance/sparkle register: 7kHz to 12kHz
Raising or decreasing the level at the lower end of this register can help bring some vibrancy and clarity, adding a tighter attack and a more pure sound. If things are a little too sharp or causing some pain after listening for too long, lowering the bottom end of this register can help out quite a bit. Toward the top is where things start to space out into less tangible definition, moving away from what you can hear and more toward what you can feel. That shimmering resonance at the tip of a cymbal crash floats around in the regions of this space.
Open air: 12kHz to 16kHz
Once you get up here, things really become more subjective. The bottom registers continue to affect the higher overtones of instrumentation, and synth effects from electronic music can pop around in that region as well. Moving further up, it becomes more about creating a spacier, more open sound. There are very few points in which you’d want to affect the sound much around 14kHz or above — many older listeners won’t be able to even hear these sounds. If you want to boost a bit of space in the belfries of the music, you can add some level here. Too much, however, will make things start to sound synthetic.
Update: This post is updated regularly for relevancy.