Whether you're mixing in the semi-pro studio or in your bedroom: the EQ is an important but elusive tool. Independent of recording the tracks, there are certain basic frequency ranges for all instruments that you need to be aware of when working with the equalizer. We take a close look at these frequencies for you in this comprehensive guide.
We've all heard of low mids, sub-bass and growl. This vocabulary (and much more) comes up quickly when musicians and fans talk about music: the sound was so crisp, the bass so harsh, the vocals really nasty (means: good). But what is bass actually? Low frequencies? How low? Or do you mean the bass guitar? Let's try to find a working definition:
- Sub bass or deep bass: everything below 60 Hz
- Bass: 60–150 Hz
- Low/lower mids: 150–800 Hz
- Mids: everything around 1 kHz, but that's particularly controversial among musicians
- High/upper mids: above 1.6 kHz, up to 3 kHz
- Treble: above the 3 kHz mark
- Airy highs/super high range: everything above 14 kHz
Anyone who talks about equalizers and frequencies also has to think about filters. The four most important:
- Low pass: This filter allows frequencies up to its target frequency to pass (limit frequency) and attenuates frequencies above that, or blocks them completely.
- High pass: This type of filter allows frequencies above its target frequency to pass and attenuates/blocks frequencies below that to varying degrees, depending on the filter.
- Band pass: This type of filter allows frequencies within a certain frequency range to pass and attenuates/blocks all frequencies outside of this range.
- Cow-tail filter (also: shelving filter): This type of filter boosts or cuts frequencies in a band (range of frequencies). The shelving filter is often used in audio technology to adjust the sound.
You should already have a good idea of the sound you want to achieve before the first recording session. For example, if you use a microphone with a directed characteristic and you get very close to it (5-10 cm), you usually get a warmer, more voluminous sound. The reason for this is the proximity effect. A clear, open, airy sound is created with one large diaphragm condenser microphone from which you maintain only a low distance (10-20 cm) while singing. The choice of the room, the microphoning and the acoustics [###Link zu: www.img-stageline.de/magazin/proberaum-raumakustik] are also important.
Remember: the basic sound of the vocal track comes, you guessed it, from the singing. The equalizer is a tool for improvement, not for producing a completely "new" voice.
The important frequencies for the vocals:
The frequency range of the human voice is between 80 Hz and 12 kHz, sometimes even higher in the overtone range.
- Below 50 Hz: Cut! In most cases, you can even set a low-cut filter from 80 Hz (male) or around 100 Hz for female vocals. The frequency range below that is not relevant for the vocals, but can affect the overall mix unfavourably – so do away with it. By the way: a low-cut filter is also often referred to as a hi(gh)-pass filter.
- 250–350 Hz: Most basic tones of voices are between 120 (male) and 250 (female) Hz. Singers with an extremely deep voice are the exception. Many newcomer mixes sound a little muddy, not nuanced. This can be intentional if you're playing Crowbar or Black Flag, but most of the time it's not. The problem of the swampy sound occurs especially in bands with two guitars and vocals. The fundamental tone range of the guitars gets in the way of the fundamental tone range of the vocals and thus also your desired vocal sound. At least if you don't take countermeasures. Here you have to operate a little, more with a scalpel than with a sledgehammer: Reduction of approx. 3 dB at approx. 300 Hz. But this only works with voices that reach a certain fullness. If the voice is rather thin, a cut at 300 Hz is more likely to do damage. If a voice is very thin, it can even help if you boost this frequency range a bit to give the voice more fullness. So the trick with the 300 Hz is not a panacea.
- 3-6 kHz: A broad, gentle boost in this area often improves clarity/brilliance and therefore speech intelligibility. If your vocal recording needs more of that, try a broad boost of approx. 2 dB between 3 kHz and 6 kHz. A rule of thumb just to be safe: after the compressor, not before! You can also use the frequencies between 3 and 6 kHz for the opposite: If the vocals sound harsh, spiked, or shrill, lower it.
There is a saying: cut before you boost. But beware!
Better to lower/cut than to raise/boost. So for warmer vocals you should cut the highs instead of boosting the lows. The general rule: if you want something to sound better, you should rather lower the frequencies. Because if you raise the frequencies, you change the sound and character significantly (which can also be intentional). And you make parts of the track or the whole track louder, in a way you take away the air to breathe (keyword: dynamic limit). Also looks for disturbing room resonances in the track and lower the affected frequencies.
"clean up" the signals then comes the compressor. It's different with drums. The EQ before the compressor significantly influences the control behaviour of the compressor. This is often not desired. So the EQ is better behind the compressor."— Marco Drewes, musician and technician for IMG STAGELINE
Boosts of more than 5 dB are dangerous
Of course, the 5 dB can only be a reference value. But it's good self-control to keep the vocals sounding natural. Very strong increases and decreases leads to subjectively clear results in the mixing, but mostly seem strange to uninvolved listeners.
The drum sound is the motor of your mix. Each drum mix is a little different. The complexity lies in the fact that the drum kit is basically a group of different instruments that have to work together.
Adjusting equalizer for kick drums
Here we usually want a fat, bass-heavy punch from the low frequencies in combination with a driving kick from the mids. The nuances look like this:
- 50-100Hz raise to boost the low bass. Be careful not to get in the way of the bass guitar here. Or the double bass. Or the cello. You have cellos in the band, don't you?
- lower by 150-250Hz if you can already hear the kick. This reduces the booming of the kick drum and provides room for the lower bass frequencies. The low frequencies then sound fuller without the overall sound becoming muddy.
- 300-600Hz is a rather dangerous frequency range, there's often mud here. Therefore: lower it! In harder genres, this is lowered reflexively to make the kick fatter. But it doesn't (always) have to be that way.
- 2-4 kHz are frequencies with which you can make a kick drum (and the rest of the drum kit) much more dominant. So if the drums don't quite come through, start here. 2 kHz is the playing field for a strong rock drum.
- In the 10+ kHz range there is little to do. Kick drums rarely need this high end. Here you can work with a corresponding filter for that last bit of focus in the kick drum sound.
Adjusting equalizer for snare drums
A lot of what we describe here can be transferred to other parts of the drum kit. But not everything.
Snares tend to produce overtones, which we don't want. That is a slight rattling and ringing that disturbs the mix. To rectify this, do the following: use a separate EQ. Set a low Q factor . Increases the level all the way up (+10 dB is fine). Now listen to the entire frequency spectrum using a parametric equalizer . The disturbance frequency will sound particularly annoying. You can then lower it. You do this as often as necessary until the unwanted frequencies are removed.
The following additional frequencies are interesting for the snare:
- at 150 Hz, raise it a little if the snare still has too little power in the mix.
- 500Hz is a frequency that you can easily raise if the snare lacks body, needs to sound fuller, needs more muscle.
- 3 kHz is the area that gives a snare drum clarity and punch.
- 6-10 kHz brilliance range
- Everything above 10 kHz is rather uninteresting or undesirable
Adjusting equalizer for the toms
With toms it's quite easy. We want a lot of pressure here on the one hand and a little less rattling of the shells. You eliminate the rattling by cutting off a few mids. You get the punch by increasing between 5 kHz and 7 kHz, depending on the size of the tom. With larger ones, it's more the higher frequencies.
Depending on taste, we strengthen the bass. This also depends on the diameter of the tom. Stand-up toms sound fuller when boosted at very low frequencies, such as 80 Hz, while smaller toms need a boost closer to 250 Hz.
The guitar has such a wide range that it often cuts into the frequencies of the other instruments. So you have to pay attention to a lot of boundaries. Here a spectrum analyser (also: RTA, Real Time Analyser) help to visualise the relevant frequencies of the individual instruments. This is at least interesting for other instruments in the mix, and often helpful. Ultimately, of course, it's the ear that decides.
- 50–60 Hz: in this area, the guitar competes with kick drums, basses and synths. Our tip: find the lowest note of the guitar in a song and then apply a high pass filter just below that frequency. With normally tuned 6-strings this is usually the low E (82.4 Hz). This leaves room for the bass and kick drum. The electric guitar has a lot of energy in the middle frequencies, so you don't need anything below 80 Hz.
- 100–200 Hz: Here is usually the basic tone of the snare. If an electric guitar with a deeper bass is important to you, raise it towards 100 Hz and make a little room there with the snare.
- 150 Hz: this is where the electric guitar gets a real boost. By carefully tweaking the bass and guitar EQ around this point, you can alter the balance of the two instruments. That way, they fit better together in the mix. Otherwise, especially when the guitar is playing chords, it will collide with the bass guitar, not only in the low frequencies, but also in the lower mids. This will cause the mix to become muddy. Lowering the guitar around 100-150 Hz will fix this problem. Solo guitars have less of this problem.
- 200–500 Hz: guitars with a lot of emphasis in this range sound warmer. If your guitar needs some warmth, then a boost at 250 Hz makes sense. But be careful, too much emphasis creates mud.
- 500 Hz - 1 kHz: this is where the "body" of the sound comes from. Some snares have their overtones in this range. It's up to you to decide who gives way to whom.
- 3 kHz: this is where guitars are often "built up" in the mix. Here, there is competition between cymbals and electric guitar, usually the cymbals "eat up" the guitar, especially with washed-out cymbals or open hi-hats.
- 5-10 kHz: clarity and openness. If you boost here, you'll achieve a "floating" lead sound. If the sound is uncomfortably intrusive or tiring, you urgently need to reduce here. In this area you often find unpleasant resonances. You can tame these problem frequencies with a "surgical" equalizer or careful use of multi-band compression.
- 10–12 kHz: When recording, this is the frequency range with which you set the brilliance. This is often more important for acoustic guitars than for electric guitars. In the mix, however, this can then collide again with the upper frequencies of the cymbals.
An important step for better mixes is an optimised low-bass component, as far as one can speak of an optimum in art. Too much bass can make a mix muddy and imprecise, too little can make the mix thin and bloodless.
High Pass Filter (HPF)
Never underestimate the High Pass Filter (HPF) when it comes to bass guitar or other instruments where low bass is important, such as bass drums or keyboards. You can use the HPF to reserve space for the bass guitar by placing an HPF where it makes sense for instruments where the low bass isn't important. Many mixers and consoles have an HPF in their channel strip, often around 80 Hz. The HPF is particularly useful when recording instruments with little deep bass, such as hi-hats. Also for a singer the only sound around 80 Hz is the rumble of the microphone stand or the resonance of the wooden stage caused by feet tapping to the beat. Therefore: eliminate structure-borne noise! Give the bass air by pushing other instruments through the high-pass filter.
However, HPFs are not just reserved for instruments with medium and high frequencies. Using an HPF to gently roll off the sub-bass range of a bass guitar can greatly improve the bottom end of a mix. Using an HPF on a bass guitar between 40 and 50 Hz can make a big difference. After all: an accumulation of sub-bass components is mostly bad. The entire low bass merges into a muddy, inarticulate mess and instruments are then almost indistinguishable. Also, many home speakers are not designed to reproduce sub-bass below 60 Hz. Here the HPF is a good cleaning agent!
Low Pass Filter (LPF)
The fundamental tone frequencies of a 4-string bass guitar in normal tuning are between about 40 Hz and 400 Hz. Otherwise, the bass guitar has additional overtones that go up to 5 kHz. In this case, a low-pass filter (LPF) is a powerful tool. Just as an HPF cuts the low frequencies, an LPF cuts the high ones. Since a bass guitar has few significant overtones beyond 5 kHz, filtering the highs puts the instrument in its own space. This takes it out of competition with other mid-dominated mixing elements
Kick drum and bass guitar belong together in the mix
Either the kick drum or the bass guitar should take the lead at the bottom end of the mix. If you level both out in a similar way, the two will fight for space in the mix, which in turn will result in an inarticulate bass end. In many cases both can have their own space in the mix thanks to the equalizer. This means, if you boost the kick at 100 Hz, you can lower the bass guitar at 100Hz. If you boost the bass guitar at 500 Hz, you'll want to roll off the kick at 500 Hz to prevent the two from competing for space in the mix. Your equalizing ultimately depends on which instrument you choose for the low-end groove. But the two should work together and not compete with each other.
Important frequency ranges for the bass EQ
Here again, as with all other instruments, is the frequency cheat sheet:
- 80–200 Hz: boosting in this area adds some richness, depth and body to the bass and solidifies a robust low end.
- 200–300 Hz: it tends to get muddy in the range from 200 to 300 Hz. If you find that your bass guitar is lacking in clarity, try rolling the frequencies in that range. If the whole mix is muddy, you might want to turn that area down a bit on the mix bus.
- 500–1000 Hz: if you need more low-midrange and punch, boost that area.
- 2.5 - 5 kHz: attack! An increase in this range gives your bass guitar more bite. Let's slap!
Mixing is more of an art than a science. Consider this guide a suggestion, not a panacea. Ultimately, the best thing you can do is simply experiment freely and wildly – or sometimes cautiously – try out what sounds good or not so good in your mix. You can also learn from bad mixes! Good sound is relative and tastes differ. That's why mixing always includes a portion of gut decision and a large pinch of subjectivity. Be brave!
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