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Equalizer (EQ) Frequency Finder

Drag across the spectrum to hear and identify any frequency. Switch on the EQ-boost sweep to use the classic mixing trick — push a narrow boost through your ear until the problem frequency jumps out. Labeled EQ zones, instrument range overlays, and a problem-frequency guide make it a complete EQ reference. Audio is generated locally — nothing is recorded or uploaded.

1.00 kHz

note —

Midrange

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Frequency 1000 Hz

Volume 25%

Tone mode plays a pure sine at the selected frequency. Switch to EQ boost sweep to push a +12 dB peak through pink noise — drag the cursor to hunt for harsh or muddy frequencies the way engineers do.

Instrument range overlay

Toggle an instrument to highlight its fundamental + harmonic range on the spectrum above.

Problem-frequency guide

Click a band to jump the cursor there — then press Listen in EQ-boost mode to hear what it does.

The Seven EQ Zones & How to Use Them

Audio engineers split the audible spectrum (roughly 20 Hz – 20 kHz) into seven working zones. Each has a characteristic job in a mix, and each has a failure mode when there's too much or too little energy. Knowing where things live is the difference between EQ-ing by ear and EQ-ing by guesswork.

Sub-bass (20–60 Hz)

Felt more than heard. This is the rumble of a sub kick, the lowest notes of a synth bass, cinematic impact. Too much makes a mix muddy and eats headroom; too little makes it thin on big systems. Most small speakers and laptops can't reproduce it, so check on headphones or a sub.

Bass (60–250 Hz)

The fundamental of kick, bass guitar, and the low end of most instruments — the "weight" of a mix. The 200–250 Hz region is the first place a mix turns muddy when too many instruments stack up here.

Low-mids (250–500 Hz)

Warmth and body. A boost adds fullness; a cut cleans up "boxy" or "cardboard" tone. This is the single most common place to cut a few dB to open up a cluttered mix.

Midrange (500 Hz – 2 kHz)

Where the human ear is most sensitive (the Fletcher–Munson curves peak around 2–4 kHz). The body and presence of vocals and most instruments live here. Boosting too much sounds "honky" or telephone-like; cutting too much makes things distant and lifeless.

Upper-mids (2–4 kHz)

Attack, definition, and intelligibility — consonants in speech, pick attack on guitar, the "crack" of a snare. A small boost increases clarity; too much causes listening fatigue and harshness.

Presence (4–6 kHz)

The "in your face" detail band. A gentle lift makes a vocal cut through a busy mix. Overdone, it gets edgy and brittle, and exaggerates sibilance just above it.

Brilliance / Air (6–20 kHz)

Sparkle, sheen, and "air." Cymbals' shimmer, the breathiness of a vocal, the top of an acoustic guitar. A broad high-shelf boost here adds expensive-sounding polish; too much sounds hissy and fatiguing.

The sweep technique — how engineers find a problem frequency

Switch this tool to EQ boost sweep mode. It applies a narrow +12 dB peaking boost to pink noise (a full-spectrum sound). As you drag the cursor, the boosted band moves with it. When you land on a frequency that sounds harsh, boxy, or resonant, you've found the problem region — in a real EQ you'd then cut there instead of boost. Lower the Q for a wide, musical band; raise it for a surgical notch. This boost-find-then-cut workflow is the fastest way to clean up a recording.

Frequently Asked Questions

What's the difference between Tone and EQ-boost sweep modes?

Tone plays a pure sine wave at the selected frequency — useful for hearing the actual pitch, testing speakers, or matching a ringing tone. EQ boost sweep plays full-spectrum pink noise through a peaking filter with a big boost at the cursor frequency. As you drag, you hear that band of the spectrum emphasised — exactly how a mixing engineer "sweeps to find" a problem frequency before cutting it.

Why can't I hear the lowest or highest frequencies?

Two reasons. First, most laptop and phone speakers roll off below ~150 Hz and above ~16 kHz, so sub-bass and air simply aren't reproduced — use headphones or studio monitors. Second, human hearing naturally declines at the extremes, and high-frequency sensitivity drops with age (many adults can't hear above 15–16 kHz). The on-screen cursor still shows the exact frequency even when your gear can't play it.

What is "mud" and where is it?

"Mud" is excess energy roughly in the 200–500 Hz region, where the low-mids of many instruments pile up. A muddy mix sounds like a blanket is over the speakers — lacking clarity and definition. The fix is usually a gentle broad cut (2–4 dB) around 250–400 Hz on a few of the offending tracks, not one giant cut on the master.

Where is sibilance and how do I fix it?

Sibilance — the harsh "ess" and "sh" sounds on vocals — lives around 5–8 kHz (sometimes up to 10 kHz on bright voices). Sweep the EQ boost in that range while the vocal plays to find the exact peak, then use a de-esser or a narrow dynamic cut there. A static EQ cut works too but can dull the whole vocal.

Should I boost or cut when EQ-ing?

As a rule of thumb, cut to fix problems and boost to add character. Cutting is subtractive and tends to sound more natural, and it frees up headroom. The sweep technique here uses a temporary boost only to locate the offending frequency — once found, you switch to a cut at that same frequency in your DAW.

Why pink noise instead of white noise for the sweep?

Pink noise has equal energy per octave, so it sounds balanced across the spectrum to human ears — roughly how music is distributed. White noise has equal energy per Hz, which makes it sound very treble-heavy and masks the lower bands. Pink noise lets the moving boost stand out evenly whether you're in the bass or the brilliance region.

Is my microphone or audio being recorded?

No. This tool only generates sound (a sine tone or filtered pink noise) using the Web Audio API and plays it through your speakers. It never requests microphone access, never records, and never uploads anything. Everything runs locally in your browser.

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