What is AIR-66?

AIR-66 is built on a simple idea: making music should be easy to start, fun to play, and good enough to use.

Easy — pick a sound, press a key, hear something musical straight away. No patch cables, no manual, no setup.

Fun — chord pads, an arpeggiator, a groove recorder, drum kits with classic patterns, a harmony panel. Tools that invite experimentation rather than demand expertise.

Quality — the sound engine runs real virtual analog synthesis with filters, envelopes, effects, and a professional signal chain. What you record is production-ready.

Whether you want to sketch a melody, jam over a drum loop, or capture a full arrangement — AIR-66 is designed to get out of your way and let you be creative.

Getting Started

Open the synthesizer in any modern browser — Chrome, Edge, Firefox, Samsung Internet, or Safari on iPhone/iPad. Sound starts on your first keypress or tap — no setup needed.

To make your first sound: press any key in the A–L row or W E T Y U O P for sharps. You'll hear the current preset play.

Features at a Glance

Playing Notes

Keyboard Layout

Your computer keyboard maps to a piano using physical key positions — it works the same on any keyboard layout (QWERTY, AZERTY, QWERTZ, etc.).

The key to the right of L plays the top E note — it's the ; key on QWERTY, ö on Swedish, m on AZERTY.

You can hold multiple keys at once for chords. The synth supports up to 16 simultaneous voices.

Octave Control

The Oct –– / Oct – / Oct 0 / Oct + / Oct ++ buttons shift the keyboard up or down by octaves. Oct 0 is the default (middle range). Use Oct – or Oct –– for bass, Oct + or Oct ++ for high leads.

The current range is shown in cyan next to the Oct buttons (e.g. C4–E5). The C keys on the piano keyboard also update their label — C4 and C5 — to always show the actual octave being played.

Choosing a Sound

The Sound dropdown at the top controls the synthesizer preset. There are 35 carefully curated vintage presets recreating classic synthesizers — basses, keys, leads, pads, bells, and more.

The same sound is used for both your keyboard playing and any chords/arpeggios.

Chord Pads

The numbered pads (1–8 on your keyboard's number row, or the on-screen pad buttons) trigger chords or arpeggios depending on the mode selected.

Press 0 to toggle between two rows of 8 pads (pads 1–8 and pads 9–16), giving you access to all 14 chord types.

Accompaniment Modes

Use the Pads dropdown to choose how the pads behave:

Arpeggiator

When using Arp or Keyboard Arp mode, the arpeggiator cycles through notes at the current BPM. You can adjust:

• BPM — drag the tempo slider, or click the number to type a value directly (press Enter or click away to confirm)
• Direction — Up, Down, Up-Down, or Random
• Octave Range — how many octaves the arp spans (1–4)
• Latch — keeps the arp running after you release the key/pad

Effects

The effects chain processes all audio before output. Controls are in the Effects panel:

Each effect has a mix/amount knob and can be dialled back to zero if not needed. The master volume slider controls the overall output level.

Groove Recorder

The Recorder section (click RECORDER ▼ to expand it) lets you record and loop your playing.

Basic recording

1. Set the number of bars using the dropdown next to the controls.
2. Press ⏺ REC — a 4-beat count-in plays, then recording starts.
3. Play notes. The bar indicators show your progress through the loop.
4. When the loop wraps around, overdub keeps adding notes on top.
5. Press ▶ PLAY to stop recording and start playback, or press REC again to re-record.

Layers

To record multiple parts with different sounds:

1. Record your first part, then click + LAYER to stage it.
2. Change the sound and record a second part.
3. Press ⬇ SAVE to commit all layers as a named recording.

Each layer is automatically assigned to the next available track slot, or to the slot that already holds the same patch. Click clear in the Layers strip to discard staged layers and start fresh.

The track faders below the keyboard show the patch name for each active track — Track 1 always reflects your current live sound, and Tracks 2–8 update as recordings are loaded.

Saved recordings

Saved recordings appear in the table below. Press ▶ to start playback; press ■ to stop.

Renaming recordings

Double-click the name of any saved recording to edit it inline. Press Enter or click away to save the new name.

Playing multiple recordings together

You can layer saved recordings on top of each other live. While one recording is playing, press ▶ on another — it will join the mix on the next downbeat so both stay in sync. Each playing row flashes green on the downbeat as a visual sync indicator.

Press ■ on any row to remove just that recording from the mix. The others keep playing undisturbed.

Recordings with different bar lengths work automatically — a 1-bar loop will repeat inside a 4-bar loop, and a 4-bar loop will play in segments alongside a 1-bar loop.

Step grid

The step grid appears automatically whenever the recorder is open. It works with any sound — synth presets show a full pitch grid from C1 to B6 (higher notes at top, like a DAW piano roll); sampler patches show one row per sample.

• Click any cell to toggle a step on or off.
• Use the ◀ ▶ arrows to navigate between bars.
• Change the number of bars with the Bars dropdown — the grid resizes immediately.
• Press ▶ PLAY to loop the grid. The yellow playhead moves across the steps in time.
• Press ⏺ REC while the grid is visible to also capture live key playing — notes snap to the nearest 1/16th step and appear in the grid in real time. The arpeggiator also writes into the grid when recording.

When a SCALE is set, the row labels in the grid are colour-coded: teal rows are in the scale, dimmed rows are outside it. This makes it easy to see which pitches fit your key at a glance without changing any sound.

Editing a saved recording

Each row in the saved recordings table has a ✎ (pencil) button. Click it to load that recording back into the step grid for editing. The recorder expands automatically, the BPM and bar count are restored, and the grid fills with the original pattern.

A patch selector appears inside the recorder bar while editing — use it to reassign the recording to a different sound without leaving the recorder. Your current live sound is not affected and is restored when you exit edit mode.

Make your changes — toggle steps on or off, change the patch, record new overdubs — then press ⬇ SAVE to overwrite the original recording. A cyan Editing: name badge in the recorder header shows that you are editing rather than creating a new recording. Click the ✕ on the badge to exit edit mode without saving.

Sampler & Drums

Selecting a [SAMPLER] preset switches the engine from synthesis to sample playback. Each key triggers a different WAV sample from the chosen pack. Sampler packs appear at the bottom of the Sound dropdown under a DRUM KITS group.

In sampler mode the step grid shows one row per sample instead of the pitch grid, so you can programme a beat by clicking the cells for each drum hit. Everything else works the same — live recording, playback, saving, and editing all behave identically to synth mode.

Drum kits and bass sounds come with built-in pattern presets. When a drum kit or bass sound is selected and the recorder is open, a PATTERN dropdown appears in the recorder bar. Choosing a pattern loads it into the step grid instantly — ready to play or customise. Bass patterns automatically transpose to the current ROOT key, so selecting a pattern always sounds right in whatever key you are in.

Using on Mobile

The synth works on all modern mobile browsers — Safari on iPhone/iPad, Chrome and Firefox on Android, Samsung Internet. The layout adapts automatically when it detects a touch screen.

Piano keyboard

On touch devices each key is at least 52px wide — large enough to tap reliably. The keyboard scrolls left and right if not all keys fit on screen. Swipe within the grey border above or below the keys to scroll, then tap a key to play it.

Use the Oct – / Oct + buttons to shift the pitch range up or down. You don't need to scroll to reach a different octave — just tap an octave button and the same visible keys play at a higher or lower pitch.

Chord pads

On touch screens a 1–8 / 9–16 toggle appears above the pad grid. Tap 9–16 to switch to the second row of chord types, and 1–8 to switch back. The active row is highlighted.

MIDI

The synth supports both MIDI input and MIDI output via the Web MIDI API (Chrome and Edge on desktop and Android).

MIDI Input

Connect a MIDI keyboard or controller before opening the page. The MIDI status indicator in the controls panel shows whether a device is detected, and a small ch: display next to it shows which MIDI channels notes are arriving on. Note-on and note-off messages play and release notes directly, spanning all octaves of your controller regardless of the octave shift buttons. All accompaniment modes (Chord, Arp, Keyboard Arp) are fully supported from a MIDI controller.

The Track 1 fader (labelled with your current patch name) controls the volume of MIDI keyboard input — drag it down to reduce the level or silence the input entirely. This also sends a MIDI volume message to any connected MIDI output, so hardware synths with local control on will respond to the fader as well.

MIDI Output

The Out: Off dropdown next to the MIDI indicator lets you send notes to any connected MIDI device or virtual MIDI port. Select a destination and every note you play — on the keyboard, via the arpeggiator, or from a MIDI controller — is also sent to that output in real time.

This lets you use the synth as a controller or sequencer for external hardware and software:

• Play the keyboard and trigger a hardware synth or drum machine
• Run the arpeggiator and record the MIDI pattern into a DAW
• Use Chord Pad mode to send full chord voicings to another instrument

Desktop

Works in Chrome and Edge. Firefox and Safari do not support Web MIDI without a plugin.

Mobile (Android)

Chrome for Android supports both MIDI input and output. Connect a USB MIDI device using a USB-OTG adapter, or use a Bluetooth MIDI controller — Chrome will detect it automatically.

Harmony Panel

The Harmony panel has two interactive circles side by side — the Circle of Fifths and the Chord Wheel. Use them to explore chords, plan progressions, and trigger the arpeggiator, all without a MIDI keyboard.

Circle of Fifths

The left circle maps all 12 keys so harmonically related keys sit closest together.

Setting the key

Use the ROOT and SCALE dropdowns — found directly below the patch selector at the top of the page — to set your key. The circle updates instantly — the root lights up in blue, and the other chords in the key light up in green. A short description of the selected scale appears below the dropdowns as a reminder.

Setting a ROOT and SCALE affects the whole instrument at once: out-of-scale piano keys are dimmed so wrong notes are harder to hit, the Circle of Fifths colours update, and the step grid rows are tinted to show which pitches are in the scale.

You can also double-click any segment on the Circle of Fifths to make it the new root. The ROOT dropdown updates to match.

Playing chords

Hold any segment to hear that chord. Release to let the sound fade naturally — the release length follows the preset's envelope, so pads fade slowly and plucks stop short.

Each chord is voiced with the root and fifth in the lower octave and the third an octave higher — an open, wide sound rather than a stacked cluster. The chord quality (major, minor, diminished) is determined by the active scale, so every chord fits the key.

While a chord is held, the PLAYING display shows all three notes with the root in brackets followed by the chord name in cyan (e.g. [G4] B4 D5 G). It clears when you release.

Following the suggestions

When you play a chord, the circle highlights the chords that most naturally follow it in orange. These are based on standard harmonic movement for each scale type:

• In major, the V chord points back to I and vi
• In Dorian, the IV chord resolves strongly to i
• In Phrygian, the ♭II chord resolves to i (the Phrygian cadence)
• In harmonic minor, the V major chord pulls strongly to i
• In blues, the ♯iv° chord resolves by tritone to v

Hold a chord, look at what turns orange, then move there. Repeat to build a progression.

Colour guide

Chord Wheel

The right circle is a chord picker. Select a root note, then hold any chord type to hear it — major, minor, 7th, sus2, diminished, and more.

How to use it

1. Click a key name on the outer ring to select the root note (e.g. click C). The wheel switches to chord mode and shows the available chord types for that root.
2. Hold a chord type (e.g. maj, min, 7) to hear that chord. Release to stop.
3. The wheel returns to key-selection mode on release, ready for the next choice.

You can also hold a piano key on the keyboard to enter chord mode for that note, then click a chord type on the wheel — useful when your hands are already on the keys.

Like the Circle of Fifths, the Chord Wheel updates the PLAYING display in real time while a chord is held.

Colour guide

When a scale is selected, the Chord Wheel uses the same colour language as the Circle of Fifths so both circles always agree on what's in key.

Octave controls

Each circle has its own Oct – / Oct + buttons. Shift the Circle of Fifths and the Chord Wheel independently to put chords in any register from bass to high treble.

Using the Harmony Panel with the Arpeggiator

When CHORD ARP is active, both circles drive the arpeggiator instead of playing static chords.

• Circle of Fifths: hold any segment and the arp starts immediately on that chord. The chord quality follows the active scale — major, minor, or diminished. Release to stop.
• Chord Wheel: select a root, then hold a chord type — the arp plays that chord type. Release to stop.

Switching to a different segment while holding restarts the arp on the new chord straight away. All arp settings — speed, direction, octave range, latch — apply exactly as they do with the chord pads.

What's Playing Display

The strip between the controls and the keyboard shows two live indicators:

• PLAYING — the notes currently sounding plus the chord name. A single note shows as its name (e.g. C4). Multiple notes show with the lowest wrapped in square brackets to mark the root, followed by the chord name in cyan (e.g. [C4] E4 G4 Cmaj7). This updates in real time as you press and release individual keys — on a MIDI controller, releasing one note of a chord immediately removes it from the display and the chord name updates to match the remaining notes. The chord is detected automatically from any source: your computer keyboard, a MIDI controller, chord pads, the Circle of Fifths, or the Chord Wheel. Recognises 29 chord types including major, minor, all 7th variants, sus2/sus4, add6, add9, 9th, 11th, 13th, shell voicings (no 5th), diminished 7th, minor-major 7, augmented 7, minor 6th, minor 9th, major 9th, 6/9, power chords, and more — in any inversion. Note names use flat spelling (Bb, Eb, Ab) when your key centre is a flat key, and sharp spelling (A#, D#, G#) otherwise.
• VOICES — the number of active audio voices. Turns orange above 5, red above 10.

Audio Meters

Two meters sit above the step grid and show the signal level of the final mix in real time.

Both meters have a hold line — a thin vertical marker that sticks at the highest recent level and decays slowly after 2 seconds. A hold value shown to the right of the main readout tracks the same peak, so you can read the maximum without watching continuously.

Metronome

The Metronome button toggles an audible click track at the current BPM. The downbeat (beat 1) has a higher pitch click to help you find the start of each bar.

When you start recording, the metronome automatically turns on for the count-in and stays running during the loop. It returns to its previous state when you stop.

BPM and Tap Tempo

Set the BPM by clicking the number display and typing a value, or dragging it up/down. To tap in a tempo, press the TAP button in time with a track — the synth averages your last 8 taps and sets the BPM automatically. Tapping resets after 2 seconds of inactivity.