EQ TRAINER
Drag the bands on your own track and hear what changes. Push too far and it names the problem: boomy, muddy, harsh, or brittle. Full explainer underneath.
Drag a node up/down to boost or cut, left/right to move the frequency. Scroll over the graph (or use the slider) to change the selected band's Q. Hit Bypass EQ to A/B against flat. Headphones or real speakers — phone speakers hide the low end.
THE THEORY
01What an EQ actually is
EQ — equalization — is just volume control that's split up by frequency. Instead of turning the whole sound up or down, you turn up or down only a chosen slice of it: the low rumble, the boxy mids, the airy top. That's it. No magic. It's a sculptor's tool — you're removing and shaping what's already there, not adding something that was never recorded.
Almost every mix problem people reach for plugins to solve is an EQ or balance problem first. Learn to hear where a sound lives and you've learned most of mixing.
02This is a parametric EQ
The EQ above is a parametric EQ — the most flexible and the most worth learning. Every band gives you three controls:
Frequency
Where the band acts. Drag left/right. The "which slice" question — 80 Hz is weight, 3 kHz is presence, 12 kHz is air.
Gain
How much you boost or cut, in dB. Drag up/down. Up adds that slice, down removes it.
Q (width)
How wide or narrow the move is. Scroll over the graph. Low Q = a broad, musical curve. High Q = a tight, surgical notch.
Filter type
The shape of the band — bell, shelf, or pass filter (see below). Parametric EQs let you pick.
Other types you'll meet: a graphic EQ gives a row of fixed-frequency sliders (fast, but you can't move the frequencies); a shelving / "Pultec" style EQ makes broad, gentle, musical curves and is loved on mix buses. Parametric teaches you the most because you control all three variables yourself.
03Filter types — the shapes
Bell / Peak
Boosts or cuts around a center frequency, fading off both sides. The everyday workhorse — all five bands above are bells.
Shelf (low / high)
Lifts or drops everything above (high shelf) or below (low shelf) a point. Great for broad "more air" or "more warmth" moves.
High-pass (HPF)
Cuts everything below a point. The most useful filter there is — clears rumble and mud out of anything that isn't kick or bass.
Low-pass (LPF)
Cuts everything above a point. Tames fizzy, harsh, or overly bright sources, or pushes something back in the mix.
04Q — broad vs. surgical
Q is the one most beginners ignore and pros live by. It sets the bandwidth — how much of the surrounding frequencies your move affects.
Low Q (wide): a gentle, broad curve. For tone-shaping — "a bit warmer," "a touch brighter." It sounds musical and natural because it works the way our ears hear, in broad strokes.
High Q (narrow): a tight spike. For problem-solving — killing a single ringing resonance, a whistle, one harsh note. Surgical cuts you barely notice except that the problem's gone.
Rule of thumb: boost wide, cut narrow. Wide boosts flatter; narrow cuts fix. Scroll over a band above and watch the curve go from a rolling hill to a needle.
05Boost vs. cut
When something's wrong, instinct says boost what's missing. Usually the cleaner fix is to cut what's in the way. Subtractive EQ keeps headroom, avoids piling up energy, and tends to sound more natural. Boosting is for flavor once the problems are gone. If you're boosting everything, that's the tell you should be cutting instead — the trainer above will literally say so.
06Mid/side EQ
Normal EQ treats left and right the same. Mid/side EQ splits the signal into the mid (what's common to both speakers — usually kick, snare, bass, lead vocal) and the sides (what differs — width, stereo reverb, panned parts), and lets you EQ them separately.
Why it's powerful: clean mud out of the mid without touching the width, or add air to the sides to open a mix up without making the vocal harsh. It shines on the mix bus and in mastering. Use it surgically — it's easy to wreck mono compatibility if you go wild on the sides.
07Dynamic EQ
A normal EQ move is always on. A dynamic EQ only acts when a frequency crosses a threshold — like a compressor that works on one band. It sits between EQ and multiband compression.
Perfect for problems that come and go: a vocal only harsh on loud notes, an 808 that booms on one pitch, cymbals that spike now and then. Instead of a static cut that dulls the whole track, it ducks that band only in the moments it misbehaves, then gets out of the way. Transparent and surgical.
08One more: phase
Standard EQ is minimum phase — boosting or cutting shifts the timing of those frequencies a touch. Usually inaudible and fine. Linear phase EQ avoids that shift (great for mastering and parallel work) but adds latency and can cause faint "pre-ring" on sharp transients. Track and mix with minimum phase; reach for linear phase on the master or when EQ'ing one copy of a sound against another.
09How to actually use it
Find it by ear
To hunt a problem: boost narrow, sweep until it's obvious and ugly, then cut there. Use numbers to know roughly where to look, not what to set.
High-pass the clutter
Roll off lows on anything that isn't kick or bass. Instant clarity, more headroom.
Small moves
A few dB does a lot. If you're pulling 9 dB, the problem is probably the arrangement or the source, not the EQ.
Trust your ears
The graph is a guide. The bypass button is the truth. A/B constantly and keep the move only if it's actually better.
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