Air-G EaseQ
User Manual
Version 1.0
Four-band equalizer based on BezEQ3 by Airwindows.
Original source code released under an open license by Chris Johnson.
User Manual
Version 1.0
Four-band equalizer based on BezEQ3 by Airwindows.
Original source code released under an open license by Chris Johnson.
Air-G EaseQ is a four-band equalizer based on the BezEQ3 algorithm by Airwindows. Unlike a conventional equalizer — which uses biquad-type filters — BezEQ3 reconstructs the signal with bezier curves at a reduced sample rate. The result is wide, smooth, very musical curves, with a character that is more analog than surgical.
Each of the four bands — LOW, LMID, HMID and HIGH — has its own gain (GAIN) and its own frequency (FREQ), and can be enabled or disabled independently. On top of that there is an air boost (AIR) in the highest region of the spectrum and an interactive display that draws the equalizer's true response and lets you drag the curve with the mouse.
It belongs to the same family as Velvet, Pulse, Pop!, Taped and Volt: reimplementations of Airwindows algorithms, with their own interface and additions aimed at mixing and mastering work.
BezEQ3 does not work like a classic parametric equalizer. Instead of resonant filters, it splits the spectrum into bands and reconstructs each one with smoothed bezier curves. It has zero latency (no internal delay lines) and, set flat, it is literally transparent — and it stays transparent at any setting, no matter how extreme.
That same design decision makes the bands interactive: when you boost a frequency, something else is being cut somewhere. It does not behave like shelving filters with neat markings; that is why its frequencies are not precise cuts, but crossover points that move smoothly from one band to the next. It is not for surgical corrections: it is for shaping tone — tilting the balance, opening the highs, adding body to the lows — in a broad, organic way.
Chris Johnson describes BezEQ3 as an equalizer you voice rather than EQ: you use the bands and sweeps as suggestions and you listen to what they do. You will not get a band to separate out from the rest, nor get a range to “come forward” or fall back. It acts, more than any other EQ, as if no EQ had been done, as if the sound had been recorded that way. And even pushed to extremes, it all keeps sounding like one coherent piece.
Air-G EaseQ interface.
The four bands all work the same way. Each one has three controls: a large GAIN knob, a small FREQ knob and a round ON/OFF button. Understanding one is understanding all four.
The large knob in each section. The neutral point (0 dB, flat band) is at the center: turning right boosts the band and turning left attenuates it. Below the knob, a label shows the true dB that band is applying at its center frequency, measured directly from the equalizer's response.
By the nature of BezEQ3, the gain range is moderate and the curves are wide: they are meant to shape tone, not to make drastic cuts. A small move already has a musical effect over a whole region of the spectrum.
The small knob in each section. It moves the band's crossover point within its range. Below the knob, a label shows the current frequency in Hz or kHz. Because the bands are reconstructed with bezier curves, moving FREQ does not open a narrow cut: it smoothly shifts the whole band's center of gravity toward the lows or the highs.
The round button to the right of each GAIN knob turns the band on or off. When a band is off it stays flat (0 dB), as if it did not exist, but it keeps its knob positions: when you turn it back on, it recovers exactly the setting it had. The change is smooth, with no clicks. On the display, a disabled band shows its node in gray.
The dB number below each GAIN is not an approximate calculation: it comes from measuring the plugin's true response at the band's center frequency. That makes it the most faithful reading of how much each band is actually doing, including the interaction between neighboring bands.
The four bands cover the spectrum from lows to highs. Their frequency ranges partly overlap, so you can work the same area from two neighboring bands for wider curves.
The lowest band. It adds weight and body: kick, bass, the fundamental of low instruments. Boosting it adds punch; cutting it cleans up mud and clears the mix.
Body and warmth. This is where much of the energy of vocals, guitars and snare lives. Too much, and it sounds boxy or nasal; too little, and the mix loses body and turns thin.
Presence and definition. This is the region the ear is most sensitive to: here you gain intelligibility and attack, but it is also where harshness and fatigue appear fastest if overdone.
Brightness and air. It opens the mix, adds clarity to cymbals, strings and consonants. Boosted with restraint it adds life; in excess, sibilance and harshness. For the very top of the spectrum there is also the AIR button.
Since neighboring ranges overlap (LOW reaches 250 Hz and LMID starts at 150 Hz, for example), the same frequency can be worked from two bands. This allows wide, gradual curves — tilt or “smile” shapes — by combining two adjacent bands instead of forcing a single one.
The AIR button, to the right of the HIGH band, adds a gentle +2 dB boost above 12 kHz — a soft-sloped high-shelf. It is the classic “air” of the highest part of the spectrum: it opens things up and adds a sense of space and polish, without touching the body or the mids.
Unlike the four bands (which are part of the BezEQ3 engine), AIR is an independent filter applied at the end of the chain. It is off by default, so when you load the plugin the sound is identical to the original algorithm. Turning it on or off does a smooth fade, with no clicks, and its effect appears immediately on the display: the curve rises at the top end.
A touch of AIR sits very well on vocals, overheads, the mix bus and mastering, when you want an “expensive” brightness without adding harshness in the high-mids. As it is a fixed, gentle boost, it works as a “more air / less air” switch rather than a fine control. If you need more control over the highs, use the HIGH band as well.
The graph in the upper panel is not an approximate illustration: it draws the equalizer's true frequency response, measured directly from the processing. What you see on the display is exactly what happens to the audio — it matches an external analyzer. The horizontal axis is frequency (from 20 Hz to 20 kHz, with its values marked) and the vertical axis is dB.
The dB scale adjusts itself so the curve never gets squashed against the edges: if you make big moves, the axis grows; if they are subtle, it zooms in. On the left, the lines mark the reference dB.
On the curve there are four nodes, one per band. They can be dragged with the mouse:
Moving a node moves the matching knob and vice versa: they are the same control seen two ways. It is the most direct way to draw tone — you grab the point of the band you want to work and take it to where it sounds right. A gray node means that band is off.
The curve is recomputed only when you move a control, not continuously, and that computation happens outside the audio engine. Drawing the true response adds no load to the sound processing: the plugin is just as light with the display open or closed.
EaseQ's natural ground. Wide, smooth curves: a little more LOW for body, a touch of HIGH or AIR to open up, a slight dip in LMID to clear things. Ideal for the overall spectral balance of a track or a bus.
Boost HIGH and cut LOW — or the other way around — to tilt the whole balance toward the highs or the lows. Thanks to its wide curves, EaseQ does this kind of move very musically, without sounding processed.
Turn on AIR to add brightness at the very top without hardening the high-mids. Combined with a slight HIGH boost, it gives openness and clarity to vocals, overheads and the 2-bus.
Cut LOW and, if needed, part of LMID to remove mud and let the mix breathe. The dB labels help you dose the cut precisely.
EaseQ is not a scalpel: it is a hand for shaping tone. Its strength lies in wide, musical moves — open, close, tilt, add body — rather than surgical corrections. The display with nodes invites you to work “by eye and ear”: drag the curve until it sounds right, trusting that what you see is exactly what you hear.
It is a deliberately polarizing equalizer. If you think of a mix as a jigsaw puzzle of bands that separate and fit together, it will frustrate you: EaseQ refuses to isolate anything. But if you work “by voicing” — touching each element until it sits in its place, without it seeming like you EQ'd at all — it is exactly the tool you are after.
Air-G EaseQ was developed by Air-G Audio as part of its line of plugins based on the work of Airwindows.
The BezEQ3 algorithm is the work of Chris Johnson (Airwindows), whose original source code is released under an open license at github.com/airwindows. Air-G EaseQ is a reimplementation of the original algorithm with its own additions: independent per-band enable, the AIR air boost, gain labels measured in real time and an interactive display that draws the true response with draggable nodes.
To Chris Johnson for his tireless work on Airwindows and for sharing decades of audio processing research completely openly.
Air-G EaseQ v1.0 — Air-G Audio. The BezEQ3 algorithm is the work of Chris Johnson / Airwindows and is used under the terms of its open license.