EQ is the most fundamental tool in mixing. Every track in your mix has frequencies that sound great and frequencies that fight with other tracks. EQ is how you fix that — by boosting what sounds good and cutting what doesn't. It's also the easiest tool to misuse, because bad EQ decisions are immediately audible and hard to undo once you've trained your ears to expect the wrong sound.
This guide teaches you EQ as a process, not a collection of recipes. The goal is to give you a repeatable system: how to listen, what to cut, when to boost, and how to make decisions that serve the mix rather than the individual track in isolation.
What EQ Actually Does
EQ — equalization — is the process of adjusting the balance between frequencies in an audio signal. It works by boosting or cutting specific frequency ranges, making those ranges louder or quieter relative to the rest of the signal.
The easiest way to understand EQ is to think of it as a volume knob with a focus. A volume knob changes the overall loudness of everything. An EQ changes the loudness of specific frequency ranges — the low-end, the midrange, the high-end — individually.
EQ is not a fix for bad recordings or bad performances. If a track sounds fundamentally wrong — muddy, harsh, thin — before EQ, the fix is usually in the recording, not in the processing. EQ makes good recordings better. It can't make bad recordings good.
Types of EQ — Graphic, Parametric, and Shelving
There are three main types of EQ you need to know:
Graphic EQ divides the frequency spectrum into fixed bands (typically 31-band in PA systems). Each band can be boosted or cut. Graphic EQ is visual and intuitive but inflexible — you're stuck with whatever frequencies the bands are set to. Rarely used in mixing, more common in live sound.
Parametric EQ is the workhorse of mixing. It lets you set a center frequency, a bandwidth (Q), and an amount (boost or cut) for each band. Most DAWs give you 4–8 bands of parametric EQ per channel. This is what you'll use 90% of the time.
Shelving EQ affects all frequencies above or below a certain point. A high-shelf boosts or cuts everything above a frequency; a low-shelf does the same below a frequency. These are useful for broad tonal adjustments — "add some air to the top end" or "take the mud off the low-end" — without making narrow changes.
| EQ Type | Best For | Used By |
|---|---|---|
| Graphic | Live sound, quick tonal fixes | PA engineers, live venues |
| Parametric | Surgical cuts, problem frequency removal | Mixing engineers, all DAWs |
| Shelving | Broad tonal balance changes | All mixing scenarios |
Frequency: where the EQ boost or cut is centered. Q (bandwidth): how wide or narrow the affected range is — a high Q affects a narrow range, a low Q affects a wide range. Gain: how much boost or cut is applied at the center frequency.
Step 1: High-Pass Filter — Always Start Here
Before you do anything else with any track, add a high-pass filter. A high-pass filter (also called a low-cut filter) removes all frequencies below a chosen point. The goal is to eliminate low-end content that doesn't contribute to the character of the instrument — rumble, handling noise, proximity effect, and any other low-frequency content that muddies the mix without adding anything.
Where you set the high-pass depends on the instrument:
| Instrument | Typical High-Pass Setting |
|---|---|
| Kick drum | 30–50 Hz (preserve the sub punch) |
| Snare | 80–120 Hz (remove boxy low-end) |
| guitars | 80–120 Hz (clean up muddiness) |
| Bass | 30–50 Hz (keep sub content) |
| Vocals | 100–150 Hz (remove rumble) |
| Piano | 40–80 Hz (clean up sub content) |
| Strings, horns | 100–200 Hz (remove boominess) |
These are starting points, not rules. Listen to the track with and without the high-pass. If removing the low-end makes it sound thin and lifeless, back off. If the low-end you're removing was just mud, you'll hear the track tighten up immediately.
Use a steep slope (12 dB/octave or 24 dB/octave) for your high-pass. A gentle slope (6 dB/octave) will affect too much of the low-mids and can make instruments sound thin rather than just clean.
Step 2: The Sweep Technique — Finding Problem Frequencies
Once your high-pass is set, the next step is finding any specific problem frequencies in the track. The most reliable technique is the sweep:
- Add a narrow parametric band (Q of 4–8) to your channel EQ.
- Boost it by 8–10 dB.
- Play the track and slowly sweep the center frequency from low to high.
- When you hit a frequency that sounds harsh, honky, boxy, or just wrong — that's your problem frequency.
- Leave the boost at that frequency, then flip it to a cut of 2–5 dB.
- Compare the cut version with the original — if it sounds better, leave the cut. If it sounds worse, undo it.
This technique works because our ears are good at identifying when something sounds worse, but poor at identifying what specifically sounds bad when a track is just "okay." By exaggerating the problem (a +10 dB boost), you make it obvious. Then you flip to a cut to fix it.
When sweeping, start with the high-pass setting already applied. Don't sweep below 100 Hz with the HPF bypassed — you'll just find all the rumble you already removed. Sweep between 100 Hz and 8–10 kHz, listening for honk, boxiness, harshness, and nasal qualities.
Step 3: Cuts vs. Boosts — When to Use Each
The general rule of mixing: cut first, boost second. Subtractive EQ — removing what doesn't work — is usually more effective and less risky than additive EQ. Here's why:
Cuts are surgical. A narrow cut removes a specific problem without affecting the rest of the spectrum. It makes space for other instruments and cleans up the mix without changing the fundamental character of the sound.
Boosts are broad. When you boost a frequency, you affect everything in that range, not just the problem spot. A +3 dB boost at 3 kHz affects the guitar, the vocal, the snare, and everything else that has energy in that range. It can quickly make a mix sound boosts and hyped rather than clean.
The exception: High-shelf and low-shelf boosts are sometimes exactly what you need. If a vocal sounds dull and needs air, a gentle high-shelf boost above 8 kHz adds presence without making the whole mix louder in that range. If a bass needs more weight, a gentle low-shelf boost below 80 Hz can add fullness. These are broad, musical changes — not surgical fixes.
The right approach: cut only what's definitely a problem, then boost only if the track needs more of something. If you're boosting more than you're cutting, step back and ask whether you're solving a mixing problem with EQ that should be solved differently.
Step 4: EQ for Common Instruments
Here's a quick reference for the most common instruments in a mix:
Kick drum: High-pass at 30–50 Hz to preserve sub content. Cut around 300–400 Hz if it sounds boxy. Boost around 2–5 kHz for attack and click. High-shelf boost above 8 kHz for crispness if needed.
Snare: High-pass at 80–120 Hz. Cut around 400–600 Hz for boxiness. Boost around 2–4 kHz for crack and aggression. High-shelf boost above 10 kHz for sizzle.
Electric guitar: High-pass at 80–120 Hz (clean up mud with bass). Cut around 300–500 Hz for boxiness if needed. Cut 2–4 kHz if harsh. Presence boost around 4–6 kHz for clarity. High-shelf boost above 8 kHz for sparkle if dull.
Acoustic guitar: High-pass at 80–120 Hz. Cut 200–400 Hz if muddy. Cut 3–5 kHz if harsh. High-shelf above 8 kHz for air if needed.
Bass guitar: High-pass at 30–50 Hz to preserve sub. Cut 200–400 Hz if boomy. Cut 1–2 kHz if gritty/honky. Cut above 5 kHz to keep it focused on the low-end.
Vocals: High-pass at 100–150 Hz. Cut 200–400 Hz for boxiness. Cut 800 Hz–2 kHz if nasal. Cut 4–6 kHz if harsh on S sounds. Gentle boost at 3–5 kHz for presence. High-shelf above 10 kHz for air.
These are starting points, not rules. Every recording is different. Use these as a baseline, then listen and adjust. If your specific vocal doesn't have a harsh 4–6 kHz range, don't cut there. The EQ should follow what the track needs, not a template.
Step 5: Common Mistakes to Avoid
EQing in solo. A track that sounds perfect in solo can fight with the rest of the mix. Always check your EQ decisions in context — how does the track sit with the full mix playing? Does the cut you made create a hole that needs to be filled by another instrument? Does the boost you added make it clash with something else?
Over-EQing. If you find yourself making more than 2–3 cuts and 1–2 boosts on any single track, stop. You might be trying to fix something that EQ can't fix. A track with fundamental issues needs to be re-recorded or replaced, not processed into submission.
Not using a reference. Your ears adapt to the mix as you work on it. Compare your mix to a commercially released track in the same genre. If your mix sounds radically different in the EQ balance — much brighter, much darker, much more mid-heavy — you've probably made a mistake somewhere.
Boosting to fix a problem you should be cutting. If something sounds muddy, resist the urge to boost the top end to compensate — cut the low-end instead. If something sounds harsh, resist boosting the low-end to "warm it up" — cut the high-end. Subtractive EQ is almost always the cleaner fix.
Ignoring the high-pass. If your first move isn't setting a high-pass filter on every non-bass track, you're starting from a disadvantage. Cleaning up the low-end first makes every other EQ decision easier to hear and make.
Want to dig deeper into vocal EQ specifically? Read our complete guide to how to EQ vocals — covering deessing, presence boosting, and the specific frequency ranges that matter for vocals.