Air-G Spaces

Air-G Spaces

User Manual

Version 1.0

Multi-reverb with 16 spaces from the Airwindows “k” series.
Original source code released under an open license (MIT) by Chris Johnson.

Table of contents

1 — What is Air-G Spaces?2
2 — User interface3
3 — Fixed controls4
4 — Controls glossary5
5 — Space catalogue6
Rooms, halls & spaces6
Plates7
Special8
6 — Credits9

What is Air-G Spaces?

Air-G Spaces is a reverb that brings 16 different spaces together in a single plugin. Each space is one of the Airwindows “k” series reverbs (Chris Johnson): rooms, halls, plates, chambers and imaginary places, each with its own character and sound.

Instead of one plugin per reverb, you choose the space from a menu and the interface adapts: the image of the place appears and the knobs change their labels according to the controls that space uses. Controls a space doesn’t use are shown greyed out.

The essentials

Pick a space in the top menu, set the blend with Mix and the length with Regen, and you’re set. Everything else is fine-tuning the character. If you’re just starting out, try the spaces one by one with a sound you know well.

Two Air-G additions

Besides each reverb’s original controls, Air-G Spaces adds two of its own that are always available: a Pre Delay and an HPF (high-pass), both acting only on the wet signal. They are explained in the Glossary.

User interface

Air-G Spaces interface

Air-G Spaces interface (showing the “Plate 140” space). Knob labels change according to the chosen space.

1
SPACE SELECTOR — Menu with the 16 spaces.
2
A/B/C/D MEMORIES — Four saved settings to compare.
3
SPACE WINDOW — Image of the place the reverb simulates.
4
LOGO / SPACES — Click the logo to open the info screen.
5
KNOB 1 — 1st native control of the space (here INPUT).
6
KNOB 2 — 2nd native control (here REGEN).
7
KNOB 3 — 3rd native control (here DEREZ).
8
KNOB 4 — 4th native control (here PRE DELAY).
9
KNOB 5 — 5th native control (here MIX).
10
KNOB 6 — 6th control; greyed out if the space doesn’t use it.
11
PRE DELAY — Air-G addition, always present.
12
HPF — Air-G high-pass, always present.

Knobs 5 to 10 are generic: their label and function change per space. The catalogue (p. 6) lists what each one controls in every reverb.

Fixed controls

These elements do not change from one space to another.

1 Space selector

The menu in the top bar chooses which of the 16 spaces is sounding. Changing it updates the image (3) and the knob labels. The menu is ordered from the spaces with the most controls to the simplest.

2 A / B / C / D memories

Four memory slots to save settings and compare them instantly. Set the plugin up, pick another letter, try something else, and return to the previous one with a click. The active memory is highlighted in amber. All four memories are saved with your project.

3 Space window

Purely visual: it shows an illustration of the place the selected reverb simulates. It is not a control; it’s a quick reference so you know where you are.

4 Logo & info screen

Click the logo to open a screen with plugin information; click again to close it.

Controls glossary

Since the knobs change their label per space, here is what each control does once. In the catalogue, hovering over a knob name shows a reminder of this definition.

Regen (regeneration)
How much energy is fed back into the tail: it sets the sustain — how long the reverb is. In some spaces, at maximum it goes into near-infinite regeneration.
Derez
Pitches the whole space down and enlarges it; the centre is maximum quality. To the left, a clean stepped drop (mellower); to the right, a continuous, harsher/more digital drop. It uses Bezier reconstruction, so it sounds the same at any sample rate.
Filter
Sets the brightness of the reverb tail. In several spaces it is two-way: past the centre it can create odd overtones on purpose.
Early Ref (early reflections)
Level of the first reflections: the early bounces that give the sense of the immediate space, before the dense tail appears.
Position (“Positin”)
Moves the source within the space: from right at the mic to against the back wall. It changes tone and apparent distance, just like moving an instrument around the room to find the sweet spot.
Input / Input Pad
Level of signal entering the plate or space (how hard it hits it).
Damping
On the plates, it simulates the physical panel brought near the sheet to damp it. Higher = darker and shorter, in a non-linear way (part of the plate “colour”).
Low Cut
Cuts the lows out of the effect. In the Chamber it filters very hard (STEED-style).
Delay (Chamber only)
The time of the tape echo feeding the chamber. At minimum it modulates the pitch wildly (and uses more CPU); at the centre it works as a normal pre-delay.
Mix (dry / wet)
Blend between the dry signal and the reverb. (Unified label across spaces; in Chris’s original it might be called Dry/Wet or Wetness.)

Pre Delay and HPF — the Air-G additions

Pre Delay (bottom row)
Pre-delay in milliseconds (0–200 ms) applied to the effect input: it separates the dry sound from the reverb and allows “slapback” effects.
HPF (high-pass)
A high-pass filter (0–500 Hz) acting only on the effect, so the reverb doesn’t muddy the lows of the mix.

“Mirror” design

The bottom row (Pre Delay + HPF) is always present. When the space already has its own Pre Delay or Low Cut, the bottom knob becomes a mirror of that native control: move either one and it’s the same, the effect isn’t duplicated. When the space doesn’t have them, the bottom knob drives Air-G’s own stage. So you always have a Pre Delay and a high-pass on hand, whatever the space.

Space catalogue — Rooms, halls & spaces

These seven spaces share the same six controls: Regen, Derez, Filter, Early Ref, Position and Mix. (Beyond and Cosmos use Pre Delay instead of Position.) Hover over each control name to recall what it does.

Wood Room small room

A small, wood-paneled room. It turned up almost by accident while searching for something else: not the biggest or the glossiest, but with an immediate, warm, recognizable personality. Great for adding body without stretching things out too much.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · PositionMoves the source within the space: from close to the mic to the back of the room. · MixBlend between dry signal and reverb.

Cathedral cathedral

A cathedral where you can place yourself anywhere: from right up at the mic to the back of the hall. Every position sounds different yet remains part of the same place. Deep, coherent, with a strong sense of distance.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · PositionMoves the source within the space: from close to the mic to the back of the room. · MixBlend between dry signal and reverb.

Guitar loud room

A small hall voiced so “the air crackles with volume”, like a rock arena. Made for guitars and drums: with Position you move the source around the room and reshape tone and distance, just like an engineer nudging the kit until it sits right.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · PositionMoves the source within the space: from close to the mic to the back of the room. · MixBlend between dry signal and reverb.

Station vocal room

A small, realistic room inspired by Bowie’s vocal sound on Station to Station. Rather than adding a tail, it merges with the sound and thickens and glamorizes it. Excellent for vocals: put something sung through it and it sounds like a record.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · PositionMoves the source within the space: from close to the mic to the back of the room. · MixBlend between dry signal and reverb.

Alien Spaceship unreal space

An “unreal realistic” reverb: a vast ship with impossible geometries. It works as a giant hall or stadium, or as a bright, dreamlike ambience for synthetic sounds. With Derez you can pitch the whole space down and make it even bigger.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · PositionMoves the source within the space: from close to the mic to the back of the room. · MixBlend between dry signal and reverb.

Beyond recital hall

A surprisingly believable recital hall. It combines two engines (early reflections + tail) that make the reverb almost invisible: it sounds as if you went to a real hall and put up some mics. Keep it near the defaults and tune the length and brightness.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · Pre DelayDelay before the reverb enters (separates the dry from the effect). · MixBlend between dry signal and reverb.

Native Pre Delay: the bottom Pre Delay knob mirrors it.

Cosmos infinite ambient

Infinite-space ambient or titanic hall: the most epic yet most “playable” space in the collection. Built for infinite sustain in live use, with an automatic brake so it won’t run away as you layer sounds. Early reflections are handled by Early Ref.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · FilterBrightness of the reverb tail. · Early RefLevel of the first reflections (the immediate space, before the tail). · Pre DelayDelay before the reverb enters (separates the dry from the effect). · MixBlend between dry signal and reverb.

Native Pre Delay: the bottom Pre Delay knob mirrors it.

Space catalogue — Plates

Plate reverbs. The first two use Input·Regen·Derez·Pre Delay·Mix; the four “lettered” ones use Input Pad·Damping·Low Cut·Pre Delay·Mix. In all of them, the 6th knob stays greyed out.

Plate 140 big plate

The big plate: the classic monster, with a wide, deep, “fiery” sound — flashy and blazing. For when you want a plate but in its most imposing form.

Controls InputLevel of signal entering the plate. · RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · Pre DelayDelay before the reverb enters (separates the dry from the effect). · MixBlend between dry signal and reverb.

Native Pre Delay: the bottom Pre Delay knob mirrors it.

Plate 240 gold foil

The gold-foil plate, the little sister: cloudier, darker, more understated and murky. It tucks into the mix without dominating and adds a pleasant bloom. Surprisingly coherent even fully wet.

Controls InputLevel of signal entering the plate. · RegenFeedback into the tail: sets the sustain (how long the reverb is). · DerezPitches the space down and enlarges it; centre = maximum quality. Sounds the same at any sample rate. · Pre DelayDelay before the reverb enters (separates the dry from the effect). · MixBlend between dry signal and reverb.

Native Pre Delay: the bottom Pre Delay knob mirrors it.

Plate A · B · C · D four EMT plates

The four “lettered” plates, inspired by the EMTs atop a famous studio. They share controls but each has its own character:

Controls (all four) Input PadLevel of signal entering the plate. · DampingPlate damping: higher = darker and shorter. · Low CutCuts the lows out of the effect. · Pre DelayDelay before the reverb enters (separates the dry from the effect). · MixBlend between dry signal and reverb.

Native Pre Delay and Low Cut: the bottom Pre Delay and HPF knobs mirror them.

Space catalogue — Special

Chamber chamber / tape

A tape echo feeding a chamber, “gone wrong” on purpose: dirty, aggressive and wild. Turn Regen up and it distorts into infinite echo; Low Cut filters very hard; and Delay produces wild pitch modulations (at minimum, almost a string oscillator). More of an instrument than a “serious” chamber.

Controls InputLevel of signal entering the space. · DelayTime of the tape echo feeding the chamber; at minimum it modulates the pitch. · RegenFeedback into the tail: sets the sustain. At maximum, infinite echo. · Low CutCuts the lows out of the effect (here it filters very hard). · MixBlend between dry signal and reverb.

Native Low Cut: the bottom HPF knob mirrors it. The 6th knob stays greyed out.

Rockstar concert hall

A medium-sized concert hall — neither intimate nor stadium — voiced to sound big and present: a live-performance space, not a studio one. Just three controls to get straight to the point.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · PositionMoves the source within the space: from near the stage to the back of the room. · MixBlend between dry signal and reverb.

The other three knobs stay greyed out.

Cyber City sci-fi city

A vast, cinematic space evoking a rainy neon city — pure Blade Runner: more washes of echo and bright reflections than a concrete room. Its signature is a living “room tone” that breathes and gives the tail movement, as if you were listening into a real environment with wind and atmosphere; turn Regen up and that air intensifies. One of the largest and most enveloping spaces in the collection.

Controls RegenFeedback into the tail: sets the sustain (how long the reverb is). · PositionMoves the source within the space: from near the stage to the back of the room. · MixBlend between dry signal and reverb.

The other three knobs stay greyed out.

Credits

Air-G Spaces brings together 16 reverbs from the Airwindows “k” series, created by Chris Johnson, under a single interface with a space selector, A/B/C/D memories and two added controls (Pre Delay and HPF).

The original algorithms are the work of Chris Johnson / Airwindows and are used under the terms of his open license (MIT). The original source code for each reverb is publicly available.

Acknowledgements

To Chris Johnson, for sharing his reverb work under an open license, and for the documentation of each space that served as the basis for this manual.

Air-G Spaces v1.0 — Air-G Audio. The reverb algorithms are the work of Chris Johnson / Airwindows and are used under the terms of his open license (MIT).