The EQ Guide
| 20-40hz | Edge of human range of unwanted rumble often complete removed. |
| 40-80hz | Sub-bass or "feel" of bass. Can add low end kick or over power mix. Is not produced by small speakers.. |
| 80-250hz | Bass 100-200hz can be boosted to add fullness or cut to reduce boomy sounds. |
| 250-600hz | Fullness or some vocals and percussion. The cardboard box sound of kick drum is around 300-400hz. |
| 600-4khz | Midrange all to easy to add mudd. 800hz is where the "cheap" sound comes from. 2k-4khz is where the attack of most percussion and some other instruments reside. |
| 4-6khz | The "presence" range that determines how far out in front of the mix vocals sound. Can easily become grating. |
| 7khz | The nasty realm of siblance the unwanted "s" hiss. |
| 8-20khz | This the range of "air" or "brilliant" can add sprakle of an alive feel to sounds. |
Overview
In addition to the CHART, tips and guidelines in this article the Interactive Frequency chart is a handy reference guide for spefic instruments. It shows the breakdown what part of that instrument resides where in the spectrum. But there is a lot more to eq than knowing where the instruments are in the spectrum.
I have read comments that compression is the most misunderstood audio process but I really think it is equalization. It might be the most over and under used audio processing tool at the same time. What complicates the matter is factors intrinsic to our humanity. We perceive different frequencies different ways. Some frequencies will sound louder or quieter than there actual volume. This is why some audio hardware has a “loudness” button. Also humans usually try and fix things by addition. This translates a tendency to boost a frequency first. Often it is easier and achieves better result to cut a frequency. You can accentuate one frequency by reducing another frequency sometimes. And will tend not to muddy up the sound.Tthen of course there is the factor of listening fatigue. This affects both the listener and the producer of music. Some ranges become irritating to the listener quickly and as the producer your judgment is eroded the longer you listen.
Then there is the matter of equipment and the psychics of sound. When mixing and mastering studio monitors are preferable. The idea of monitor is to have a flat response curve across the whole spectrum and to be as transparent as possible. But there is no replacement for listening on different and greatly varying equipment especially for the getting the tricky low end right. Playing an instrument needs the same consideration to dial in the right sound also. Your practice amp, gigging amp, and the house pa is going to affect the sound differently and you have to consider how your sound is going to fit with the rest of the band. The low end is complicated by the psychics of sound as well as some other spots it the spectrum. Low sounds are harder to hear at low volumes. This is why a spectrum analyzer can be a useful tool to see what makes up a sound but you can not paint by decibels because our ears perceive sound differently than the psychical reality of sound.
Below is a list of guidelines of what frequency does what. And they are just that… guidelines. I used several sources and personal experience and experimentation to compile them. there are no hard and fast rules when it comes to eq. Sometimes I think professorial sound engineers do a disservice to amateurs and hobbyists by declaring what should be boosted and cut. it really depends on the source material and the entire mix. Also pros benefit from the skilled arrangements, professional musicians and vocalists, quality gear through out the entire signal chain, good microphone technique that mere mortals like myself do not always have. A lot of the eq advice is intend to get a “professional sound” which general means sounding like everything else on the radio that is fine but I would strongly suggest that you try and achieve the sound you want. a better understanding of the equalization will help you achieve that sound whether recording, mixing, mastering, finding that killer guitar sound or designing filters and tone sections of audio devices. Also remember equalization is not a magic bullet. If the sound is bad to start with is really does work with other sounds eq is not going to fix it. Eq is a polisher and shaper and can shoehorn tracks into a mix but it will not change water into wine.
The Low Down
20hz is the very low end of human hearing. 20-40hz is out of instrument range. This is the rumble of an earthquake, thunder of anything else earth shaking. Usually nothing desirable can come from a boost in this range. It sometimes can cause problems. Ambient sound like that of train or freeway or things moving in the room can rumble its way into ruining your mix. It is often completely filtered out. A lot of sound systems don’t even go this low.
Here Comes the Bass
40hz to 80hz or the 1st octave is the sub-bass of the “feel” of the bass. Its an important range for hip-hop, dance or electronic music. If you want to rattle an impala at a stop light or send thunderous pulse through the planks of a dance floor this range is for you. Bass is also hard to work with. These frequencies are made for sub woofers or large speakers. Small sound systems and even monitors frequency response rolls off in this region. This is compounded by psychics. Low end frequencies are not heard as well by human ears at low volumes. You often hear that you should try and listen on different and varying sound systems which is absolutely true but you should also listen at different volumes. while true of all sounds varied listening is critical in this range. Despite monitor's transparency they can under emphasize bass especially small monitors. Due to the physics small speakers have trouble replicating low frequencies. This is the reason for bass boost on small systems and headphone products. The danger here is boosting the bass to overcompensate for poor bass response or listening at low volume levels only to find it overwhelms the mix at high volumes or on systems large speakers and sub woofers that produce more bass. It usually is enough to boost just the baseline or bass drum or both to get some nice tight powerful bass. Boosting to many tracks in this area can easily over power the everything else. Often all other instrument these in this range are completely filtered out.
200hz-250hz can add fullness to vocals but also muddy things up quickly. It is a good place to start look for mud in vocals. Small reduction or boosts can be help but changes in this range can become dramatic quickly. Mud and fullness of other acoustic instruments hang out around here also. Slight boosts to fill out a thin sounding acoustic guitar is common in this range. Also this is the range the fullness of a snare and gong sound of cymbals usually reside. 250hz-600hz is the borderlands between midrange and bass. Some fullness for vocals can be found hear also. If your kick drum or other low register percussion has that icky cardboard box sound a cut some around 300hz to 400hz can get rid of it. this same range is also a good place to get space between the baseline and bass drum.
Middle of the Road
600hz-4khz is the midrange. This is tricky area. Subtly is the key for it is easy to get unintended result. In this range it is easy to induce listen fatigue. It is also the range in which sounds edge and aggressiveness come form but it is an extremely fine line even if you are making aggressive music. You can think of it as the telephone band. If you create a step bell curve over these frequencies cut almost all the frequencies on either side and greatly boost most the ones inside of the bell and you get the telephone sound. The sound referred to by a host of negative terms like cheap, plastic, tinny, toy sounding, unmusical, that is almost universally loathed is prevalent around 800hz. 800hz is the area where that can boost or reduce the punchiness of a base guitar but is most often reduced to remove that cheap sound in other instruments.
Climbing above 800hz between 2khz-4khz is the area that the attack of the beater hitting a percussion instrument and the attack of some other instruments can be accentuated or diminished. This is approaching the presence range so can determine how much the sound stands out in the mix. Sound can really mush together in this range so it can take so work to get everything to fit.
Stage Presence
4khz-6khz is usually the frequency people are talking about when the word presence is used. The presence knob on a guitar amp boosts these frequencies. These frequencies affect how close the sound seems and can help separates it form the rest of the mix. It is the range that can make vocals or instrument solos seem “up front.” It is also easy to abuse. To much boost can easily become grating and listening fatigue will almost assuredly be induced.
Sssssssssssssh!
7khz is the sibilance or “s” sound area of the frequency spectrum. This where you can reduce the unpleasant and sometimes overpowering “s” sounds known as de-essing. It can work wonders but if over applied can take the life out of the vocal track.
Way Up High
7k-8k is where the brightness of cymbals and other high register percussion is. It is often referred to shimmer or sizzle. It can all add some bite to other instruments. Sometimes boosting in this area can yield a metallic sound.
8k and above is often referred to as air, brilliance, breath sound, or sparkle. These "air" frequencies are where that unpleasant sound often referred to as the ice pick sound or brittleness can be dealt or a sound brightened up and sparkle added. 10k is a good starting point to look at adding some brilliance. 15k and above is more the area referred as “air.”
Some General Tips:
Types of eq vary greatly(it would take an article just as long to explain them all.) the best eq hardware or software is one that you like the sound of and you have a good understanding of and find easy to use.
A lot of the time the besst use of eq is addition by subtraction.
A spectrum analyzer is a good tool can be useful and is a great learning tool to see what makes up what sounds. It helps to think of the frequency spectrum in visual terms.
Remember there is a ying-yang quality to there frequency spectrum. A boost will diminish something else etc.
Don't for get panning. Eq and panning go hand and hand to help everything sit in the mix Listen to your sounds on as many different systems as possible at different volumes.
Do not rely on numbers use your ears.
Experiment nothing is set in stone.
Mix in shorter focused sessions and don't burn your ears out.
Search out more info on the web. Like GI Joe says, "Knowing is half the battle."
Have fun.
9 Free EQ Plugins
Here is 6 free eq plugins to heelp you with your tone shaping needs. This actually is a pretty thin area when it comes to free plugins. I suppose eq is not the sexiest piece of digital kit and most host come with decent eq it as not as attract to develop. I wish a few virtual analog snyths would be replaced by eq's. Oh, well. This is good stuff but if oddly enough there is not a lot choice when comes to free plugins emulating the vintage hardware eq units. You'll have to pay for the good ones like that.
Nyquisteq is great eq plugin from Magnus at Smartelectronix. the name comes from being able to handle sound up to the Nyquist Frequency without the normal problems. it handles the low end well also and and gui is uncluttered which makes all 5 bands easy to use. it is the most transparent of the eq listed here.
Kjaerhus Classic Eq has a nice emulation of classic analog sound. it is not great when precision is need but it is great for general eq tasks. Being in stereo lets you create some cool panning effects by splitting frequencies right and left. it look and acts like a graphic eq unit you might find on a lot of consumer audio equipment so it should be easy to use and comfortable to most users.
The Pariseq may not be that attractive but it sounds good and is easy to use. Unfortunately its developer's site is gone. But you can still download it here. This eq is well suited to being an "effect" as well a more typical use for an eq.
Electri-Q great all around eq.
Voc-EQ pro as is names implies is a useful tool for vocals.
Voxengo span is a real time spectrum analyzer plugin. It can help you see whats going on with your sound. a useful tool in tandem with eq.
Overtone is another free equalization plugin from voxengo. This again is made to really color the sound in a good way. it has a few more bell and whistle than the others.
KarmaFx Equalizer is a 31 band graphic eq that you might like. It has some nice options to give you a lot of control while maintaining a a simple layout.
TDAe EQ2008S is a graphic style sith eight bands stereo(8 bands each side)EQ.