AXIOM 16-P User Manual

Manual version 2.9 for app build 11.10 · a drum synthesizer, sampler and sequencer that runs in your web browser.

This manual describes every button, dropdown, slider and editor in the app and how the pieces fit together. Hover over any control in the app for a two-sentence description of it; this manual gives the longer explanation and worked examples.

How the manual is organised

Where things live in the project (for whoever updates this manual)

• The app is the folder AXIOM-16P (index.html, css, js, manual.html): copy it anywhere and open index.html in Chrome or Edge. Everything else in the project folder (tools, docs, backups, notes) is for development and is not needed to run it.
• This manual: docs/manual/*.md (source parts) → built into docs/MANUAL.md and docs/manual.html by python tools/docs/build_manual.py.
• Tooltips: AXIOM-16P/js/tooltips.js (and title attributes in AXIOM-16P/index.html for the additive panel).
• Sound-design lab and kit tools: tools/sounddesign/ (see its SOUND_DESIGN_GUIDE.md).
• History of design decisions: PROJECT_STATE.md.

Keeping this manual up to date

Every time a feature, control or behaviour changes, do these steps in the same change:

1. Edit the matching part file in docs/manual/ (the control tables are the first place to look: control | what it does | range/default). Add new controls to the table and describe new workflows in the text.
2. Update the tooltip of every new or changed control (js/tooltips.js, or the title attribute for controls in the additive panel): at most two sentences.
3. Add a line to the change log below (date, build number, what changed, which section was edited).
4. Rebuild the manual: python tools/docs/build_manual.py.
5. Check coverage: python tools/docs/check_manual.py lists every on-screen control that has no tooltip or is not mentioned in the manual. The manual is complete when both lists are empty.
6. Bump the build number (?v= in the script tags of AXIOM-16P/index.html) so browsers do not show a cached old version, and update the "Manual version" line above.

Change log

AXIOM 16-P User Manual - Part 1: The App Shell

This part covers everything around the sound editor and sequencer: starting the app, the top bar, the FILE / MIDI / SETTINGS menus, projects, kits and sets, MIDI, timing, performance and troubleshooting. The sound editor, loop rack, effect channels and sequencer have their own parts.

Control names are written exactly as they appear on screen. Where a label is shown only as an icon in the top bar (SET, KIT, STYLE), the full name is given as well. "(unverified)" marks statements that could not be confirmed in the code.

Contents

1. Quick start
2. The top bar
3. FILE, MIDI and SETTINGS menus
4. Projects, autosave, kits, sets and styles
5. MIDI
6. Time keeping and performance
7. Troubleshooting
8. Maintainer notes

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1. Quick start

1.1 Your first sound (60 seconds)

1. Open index.html in Chrome (or another modern browser). There is no install and no server.
2. Click anywhere on the page. A box reading AUDIO ENGINE READY asks for this click. Browsers keep audio silent until you interact with the page.
3. Press a pad with the mouse, or press a key on your keyboard (see 1.4). The app starts with the Techno kit loaded.
4. Press PLAY (or the space bar). Pattern button 6 plays. The button turns into PAUSE.
5. To change the drums, open the KIT drop-down in the preset bar and pick a kit. Loading a kit never changes your tempo or your pattern.
6. To change the rhythm, open the STYLE drop-down (SEQUENCE STYLE) and pick a style. This loads 16 patterns and never changes your sounds.
7. To change tempo, type in the BPM field, or press TAP at least twice.
8. To hear everything at once, open the SET drop-down (MASTER FULL SET). This loads a kit, 16 patterns and effects together.
9. Press STOP to rewind to bar 1, step 1.

If you hear nothing, open SETTINGS and press TEST SOUND. See section 7.

1.2 The three views (FULL mode)

Two toggles sit next to the view buttons:

Leaving SEQ view closes the 17-row grid again if the view had opened it.

1.3 The two modes: FULL and PERFORM

F9 switches between them. Use PERFORM live or on a slow computer. Use FULL to design and edit.

The app remembers your mode, view, sequencer collapse and pad strip state between visits (browser storage key axiom_layout_v1). You can force a layout with URL parameters: index.html?view=sound&seq=min&pads=hide&mode=perf (view = pads / sound / seq, seq = full / min, pads = show / hide, mode = full / perf). In PERFORM mode the view is always PADS.

1.4 Keyboard shortcuts

Shortcuts do not fire while you type in a text or number field. Function keys also work while a drop-down has focus. Function keys ignore Ctrl, Alt, Shift and Cmd combinations.

Pad keys are ignored while Ctrl, Cmd or Alt is held, and while a key auto-repeats.

Mouse shortcuts you will meet in this part:

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2. The top bar

The top bar has two rows. Row A (top) holds the logo, tempo, transport, master volume, meters, mode and menus. Row B holds the view buttons, swing and the preset bar.

2.1 Logo and build stamp

2.2 Tempo block (BPM, PRESET, BAR, STEP)

2.3 PRESET TEMPO and the tempo rule

Rule: loading a kit, a full set, a sequence style, a pattern slot, a pasted pattern or a patch / song JSON file never changes your tempo or swing. Each of these only remembers the tempo it was saved with. To use that tempo, press ↺ PRESET.

• ↺ PRESET sets BPM, swing and groove together.
• Pattern slots keep the tempo they were authored with.
• The big BPM display, the BPM field, the swing slider, the groove box and the source tag always show the engine's real values, whoever changed them.
• Exception: LOAD PROJECT and RESTORE (the restore banner) do set the tempo, swing and groove stored in the project file, and the source tag shows PROJECT. Undo and redo never change tempo or swing.

2.4 Swing and groove (row B)

Swing and groove change what you hear and what a WAV render contains. They do not move steps in the pattern.

2.5 Transport

Record setup window:

The METRONOME CLICK check box now switches the real click: it calls the same function as the 🔔 CLICK button.

2.6 Master volume and meters

The oscilloscope picture is hidden in the current top bar (and in PERFORM mode); only the meters remain.

2.7 Mode and menus (row A, right)

2.8 View buttons (row B, left)

PADS, SOUND, SEQ, SEQ ▾ / ▴ and PADS ▾ / ▴: see 1.2. In PERFORM mode this group is hidden.

2.9 The preset bar (row B, right)

Three levels of preset, from biggest to smallest. Labels are shown as icons when space is tight; the full name is in the tooltip.

Notes:

• The KIT list has two groups, Vintage Machines (20) and Genre & Modern (22), plus a group "New designed kits (10)" added at start-up.
• Choosing a SET also moves the KIT and STYLE drop-downs to the matching entries.
• Loading a kit replaces the two effect channels and the master compressor and reverb settings with the kit's own, and sets the master level (see section 4).
• A hidden older duplicate of the KIT drop-down exists (select-kit-preset) for older MIDI-learn mappings. It is not visible.

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3. FILE, MIDI and SETTINGS menus

3.1 FILE menu

The BAKE buttons here are exports. They are not the same as BAKE TO SAMPLE / BAKE KIT in the sound editor (those change the pads themselves).

3.2 MIDI menu

3.3 SETTINGS menu

There is no switch for MIDI clock output. It is always on when a MIDI OUT port is chosen and the app is not following an external clock.

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4. Projects, autosave, kits, sets and styles

4.1 What a project contains

A project file (.axiomproject) and the autosave contain:

• Tempo, swing, groove, loop length, click on / off and click volume.
• The master bus (volume, compressor, reverb and delay settings).
• All 16 pads: mode, mixer, synth / additive / sampler settings, final stage, crop, envelopes, and the sample audio itself (16-bit). A baked pad remembers its synth so BACK TO SYNTH still works after a reload.
• The two effect channels (effect, parameters, tempo sync, trigger mode). Sessions saved with 4 channels still load; channels 3 and 4 are ignored.
• The live sequencer tracks and all 16 pattern slots, with their names, roles, lock state, loop length and tempo notes. Also track mute / solo, chain mode and the record settings.
• The OFF 9-12, OFF 13-16 and loop power switches.

Not in a project: the loop player's audio slots (track 17) and the sound design in them, your MIDI mappings (they are stored separately in the browser and have their own EXPORT MAP / IMPORT MAP), the app mode and view, and the current drop-down choices of SET / KIT / STYLE.

4.2 Autosave and the restore banner

• The app checks for changes every 4 seconds and saves to the browser's database (IndexedDB), including sample audio. If that is not available it saves a smaller copy without samples to local storage.
• While the sequencer plays it saves at most every 20 seconds, to keep playback smooth. It also saves when you switch tabs or close the page.
• On the next start, if an autosave exists, a bar offers: "Restore your previous session (saved ...)?" with RESTORE and START FRESH.
• RESTORE loads it (including its tempo).
• START FRESH deletes the autosave.
• Until you choose, the old autosave is not overwritten.
• Autosave lives in this browser profile for this page address only. It is not a backup. Use SAVE PROJECT for a file you can keep.

4.3 Undo and redo

• 32 steps. Buttons are in FILE; keys are Ctrl+Z and Ctrl+Shift+Z / Ctrl+Y.
• A step is recorded about a quarter of a second after you change a control, click a step, draw in a lane or load a preset. Playing pads, transport buttons and view / mode / tab buttons are not recorded.
• Covered: pad settings, mixer, effect channels, sequencer steps, pattern slots, master bus.
• Not covered: sample audio (loading or replacing a sample cannot be undone), tempo, swing and click (undo never rolls them back), loop player audio, MIDI mappings, mode and view.
• Undo keeps the transport running.
• Loading a project or restoring a session starts a new baseline; its history is not undoable beyond that point (unverified: the stack is not cleared by LOAD PROJECT, but states before it contain the old tempo).

4.4 Kits, sets and styles

Behaviour to know:

• Every pad loaded by a kit starts from neutral synth defaults, so the result never depends on the kit you had before. Both FX sends of every pad are set to 0 by factory kits; the kit's effects are loaded but nothing is sent to them until you raise a SEND.
• Reverb choice: a first-time user starts with the lightest reverb, Light Room (first item of the reverb list), whatever the kit says. Once you pick a reverb yourself (or open a session saved with one), kits may bring their own reverb again (browser storage key axiom.reverbPicked).
• The pad LFO tools were removed from the app and from the factory kits (build 10.3); kits no longer contain hidden modulation.
• Loading a kit replaces everything you did to the pads, including edits and loaded samples. Use SAVE PROJECT first, or UNDO.
• Loading a style or set replaces all 16 pattern slots. Your own patterns in the slots are lost unless you saved a project. Locked slots are not protected from a style load (unverified).
• Switching pattern buttons: a single click while playing cues the pattern to start at the end of the current pattern loop. A double-click or double-tap (second click within 350 ms) starts it at the next measure line, restarting at the new pattern's bar 1 if that is mid-pattern. Stopped, a click switches at once. The cued button is highlighted; a forced cue has a stronger highlight.
• Your pattern edits are stored in its slot when you switch to another slot.

4.5 KITS LOAD AS: SAMPLES or SYNTHS

Every designed kit is stored two ways: as synth settings (live and editable) and as "printed" samples (the same sounds rendered to audio, about 1 MB per kit).

Older kits that have no designed version load their own reference samples as before (vintage sampler kits are sample-first, analogue ones synth-first) (unverified for individual kits). The setting applies to the next kit you load. Kits loaded in PERFORM mode are baked to samples automatically whichever setting is chosen.

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5. MIDI

MIDI needs a browser with Web MIDI (Chrome, Edge, Opera). If it is missing, the MIDI IN list says "Web MIDI Unsupported". The MIDI file importer still works without it.

5.1 Devices and monitor

Open MIDI SETUP > DEVICES & LIVE MONITOR.

What the app sends to MIDI OUT:

• A note on and note off (100 ms long) for every sequencer step, on the track's channel (default 10) with the step's MIDI note and velocity. Notes you play by mouse or key are not sent (unverified for live hits).
• MIDI clock (24 ticks per quarter note), Start (0xFA) when playing from step 1, Continue (0xFB) when resuming from the middle, Stop (0xFC) on PAUSE / STOP. The clock is "straight": it ignores swing.
• Controller LED messages if LED feedback is on (5.4). These go out on channel 1 on the same port.
• A follower never echoes a master's clock back.

5.2 What incoming messages do

Order of handling for a note on (channel filter applies):

1. MIDI Learn mappings you made yourself.
2. The playable pad range of the controller profile (default root note 40, 16 notes) plays pads 1-16.
3. The step range (default root note 24, 16 notes) toggles steps 1-16 of the selected track in the shown bar.
4. The default General MIDI mappings (notes 36-51 = pads 1-16), if they are still in the table.
5. Anything else is ignored, unless KEYBOARD & DUAL ROUTING is set to chromatic mode.

Notes: note-offs are only logged. Velocity of the note sets the pad level. If REC is armed the hit is recorded.

Built-in transport messages (primary input only, any channel):

5.3 MIDI Learn

To map a control:

1. Press 🎹 MIDI LEARN in the MIDI menu (or ENGAGE MIDI LEARN in MIDI SETUP > MIDI LEARN & MAPPING TABLE). Learnable controls get a dashed outline.
2. Click the on-screen control. It pulses and the banner says LISTENING FOR: <name>.
3. Press a key or pad (note) or turn a knob (CC) on your controller. A chime plays and the banner confirms the binding.
4. Click the next control, or press EXIT LEARN (banner) / DISENGAGE MIDI LEARN to leave. Bindings are kept.

To learn many at once use LEARN A SET (below): pick a set, press LEARN ALL IN ORDER and touch one key or knob per control. The banner counts the progress and SKIP ▶ leaves one out.

What you can map:

Rules:

• Controls that cannot be learned: file pickers, text boxes, the oscilloscope and the drawing canvases (waveform crop, loop waveform, partial editor).
• Navigation controls (PADS / SOUND / SEQ, the editor tabs, sub tabs and lane tabs) keep working while learn is on. Alt+click them to learn them.
• Clicks inside the MIDI setup window and the step inspector are not learn targets.
• While learn is on, clicking a learnable control selects it for learning instead of operating it.
• A new binding replaces an older binding of the same control, and also an older binding of the same note or CC number (on the same channel, or on Omni).
• Bindings are saved in the browser (axiom_midi_mappings) and survive reloads. They are not part of a project.

MIDI SETUP > MIDI LEARN & MAPPING TABLE:

Learn sets. The first group learns controls that are on screen; the mixer sets work for every pad, also when it is not selected, and for the looper (number 17):

With the pad the mixer set changes selected, the PAD CONTROLS slider follows. Learned sets are saved like any other binding (axiom_midi_mappings).

5.4 Pad controllers (AKAI and Novation split)

Open MIDI SETUP > PAD CONTROLLERS (AKAI / NOVATION SPLIT). A pad controller with 8 x 4 pads is split in two halves: the top two rows play pads 1-16, the bottom two rows toggle steps 1-16 for the selected pad.

LED colours: green = playhead, yellow = active step of the selected pad, red = a pad was hit, off = empty. The LED messages go to MIDI OUT, so choose your controller's output port there.

Overlaps: with the default AKAI profile the play range (40-55) shadows the default GM map for notes 40-51, and the step range (24-39) takes notes 36-39 for steps 13-16. Pick the Standard 4x4 profile if you want plain GM notes 36-51 on the pads.

5.5 MIDI clock out, following an external clock, clock offset

Clock out: with a MIDI OUT port chosen, the app sends 24 ticks per beat, plus Start / Continue / Stop, to whatever is connected. It does so only while not following.

Following a master (SETTINGS > MIDI CLOCK SYNC):

1. Choose the master's port as MIDI IN (USB). Clock only counts from the primary input.
2. Press ⏱ FOLLOW CLOCK. It reads ON.
3. Start the master. When the master sends Start, the app rewinds and starts on the master's next tick. Continue resumes from the current position. Stop pauses.

How it behaves:

CLOCK OFFSET (ms) shifts your beats later (+) or earlier (-) relative to the master. If your kick lands late against the master's kick, use a negative value; if early, a positive one. Start with 0 and adjust by ear in steps of 1-5 ms.

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6. Time keeping and performance

6.1 The scheduler

• The clock runs in a worker thread (not slowed down in a background tab). It wakes every 25 ms.
• Each wake-up schedules every step that falls inside the next 120 ms of audio time (the look-ahead). Steps are given exact audio times, so they do not drift.
• In a background tab, where timers can be throttled, the look-ahead widens to 0.6 s.
• If the app falls more than 0.1 s behind (for example the page was frozen), it re-syncs instead of playing the missed steps.
• The pad flashes and the playhead LEDs are timed to the audio, not to the scheduler.

6.2 Load shedding

A watchdog measures the gap between clock ticks. A gap longer than about 70 ms means the main thread was busy. Then:

• The look-ahead is widened by up to 0.4 s so the audio does not starve, and relaxes slowly after 3 calm seconds.
• Load shedding is switched on for 5 seconds: the voice limit is halved, and soft ghost notes (velocity under 0.45) on non-essential pads are skipped. Pad lights keep working.
• The first 1.5 s after PLAY are ignored, because start-up hiccups are not overload.

6.3 Voice limit

VOICE LIMIT (8-96, default 32) is the most voices that may sound at once.

• Under the limit, everything plays.
• Over it, non-essential pads (anything except kick, snare, clap, rim shot, stomp) are skipped, and a kick, snare or clap steals the tail of a hat or percussion voice.
• While shedding, the limit is halved (never below 4).
• MONO PADS reduces the number of overlapping voices a lot; try it before lowering the limit.
• In PERFORM mode the limit is capped at 16. Whatever you type there is restored to your earlier value when you return to FULL (unverified for edits made inside PERFORM).

6.4 The LOAD / DSP badge

The badge in the top bar appears only while playing.

An audio underrun (1% or more of blocks) or a peak above 92% also switches on load shedding.

What to do: bake synth pads (BAKE KIT), switch to PERFORM, turn MONO PADS on, lower VOICE LIMIT, use SLOW CPU, switch OFF 9-12 / OFF 13-16, set AUDIO BUFFER to SAFE (SLOW PC), close other tabs.

6.5 FX auto-mute

Every 500 ms the engine counts clock stalls and audio overloads. Two or more within 10 seconds mutes the effect channels that hold a reverb or modulation effect for 8 seconds, and the badge adds FX MUTED. Drums keep time. The channels return by themselves. If it keeps happening, reduce voices or bake pads.

6.6 PERFORM mode

PERFORM is the "play it live on a modest computer" mode.

If you leave PERFORM while it is still baking, the bake is cancelled and undone.

6.7 AUDIO BUFFER and slow computers

AUDIO BUFFER sets how much audio the browser buffers before the speakers.

It is saved immediately, but the audio engine is created once per page load: reload the page to apply it.

Checklist for a slow computer, in order:

1. Settings > AUDIO BUFFER = SAFE (SLOW PC), reload.
2. Switch to PERFORM (F9), or press BAKE KIT in FULL mode (keep kick + snare if you want to edit them).
3. Keep KITS LOAD AS: SAMPLES and MONO PADS: ON.
4. Lower VOICE LIMIT to 16-24.
5. Turn ⚡ SLOW CPU ON, and switch OFF 9-12 / OFF 13-16 for sounds you do not use.
6. Use fewer FX sends; keep the reverb light (Light Room is the cheapest).
7. Close other tabs and apps. Use Chrome or Edge.

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7. Troubleshooting

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8. Maintainer notes

Update this part when any of the files below change. Search for the element ids or function names given.

Open issues found while writing (verify before relying on the manual text above; remove the notes here and in the text when fixed):

1. At the last check index.html and js/app.js both said 10.2.0 (the coordinator reported 10.3); README still says v9.4. Re-check the build label text in 2.1 when the version changes. Preset-kit reverb rule: Presets.applyKit (Light Room unless axiom.reverbPicked).
2. js/project.js header comment says aux FX bays are not persisted; the code does persist them.
3. The meter's right bar is derived from the left bar's value (single peak reading).
4. The "tempo is never changed by loading" rule has one deliberate exception: LOAD PROJECT and RESTORE apply the stored tempo.

02 - Pads and Sound

This chapter covers everything that makes a single pad sound: the 16 pads, the pad editor, the three sound engines (SAMPLE, SUBTRACTIVE, ADDITIVE), the PAD CONTROLS window, BAKE, and the kits.

Conventions used in this chapter:

• Control names are written exactly as they appear on screen, in CAPITALS.
• "Range" is the slider range in the editor. "Default" is the neutral synth/engine default; loading a kit or choosing a RECIPE CATEGORY replaces most defaults.
• Most sliders in the editor are drawn as rotary knobs. Drag a knob up or down to change it. Hold Shift for fine steps. Double-click resets it to its starting value. When a knob has keyboard focus, the arrow keys, Page Up, Page Down, Home and End move it, and the mouse wheel works only while the knob is focused.
• "(unverified)" marks a statement I could not confirm in the code.
• Sections 4 and 5 describe the additive engine v2 (new in v10.2). This chapter matches build 10.3.

Contents: 1 Pads and editor, 2 Sample engine, 3 Subtractive synth, 4 Additive synth, 5 PAD CONTROLS, 6 BAKE, kits, presets, 7 Cookbook and glossary, Maintainer notes.

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1. The 16 pads and the pad editor

1.1 The pads

The 16 pads sit in a 4 by 4 grid (title: 16 DRUM CELLS // MATRIX). Each pad shows only a small number in the corner. Hover a pad to see its name and keyboard key.

Pad 17 is the separate LP pad (looper). It is covered in the loop chapter.

What you can do with a pad:

Selecting a pad also switches the right-hand deck to the PAD SOUND ENGINE tab.

Pad lights. A pad flashes for about 110 ms at the moment its sound plays, whether the hit comes from the sequencer, MIDI, a key or the mouse. Every pad lights when its sound plays, by any path (sequencer, MIDI, key, mouse, recording); your own hits always light. Use SETTINGS > PERFORMANCE / CPU > PAD LIGHTS to turn the sequencer-driven lights on or off. The selected pad has a permanent highlight.

Mute and solo. There is no mute button on the pads themselves. The MUTE and SOLO buttons in the sequencer deck header act on the currently selected track (the selected pad). They gate the steps the sequencer plays. They do not stop you from playing the pad by hand. To switch off pads 9 to 12 or 13 to 16 completely (to save CPU), use SETTINGS > PERFORMANCE / CPU > OFF 9-12 and OFF 13-16.

Hi-hat choke. Playing the pad named CLOSED HAT (pad 7) cuts any pad named OPEN HAT (pad 8). The match uses the pad names, so a renamed kit pad keeps the behaviour only if "CLOSED" and "OPEN" stay in the names, or if the pads stay in positions 7 and 8.

MONO PADS (SETTINGS > CPU, on by default). A pad cuts its own previous hit when you strike it again more than 45 ms later. Hits closer than 45 ms (flams, ratchets) overlap.

1.2 The tools under the pads

View keys: F1 PADS, F2 SOUND, F3 SEQ, F4 collapse sequencer, F8 hide pad strip, F9 FULL / PERFORM.

1.3 The pad editor and the three engines

The PAD SOUND ENGINE tab shows the title bar "PAD n: NAME" and three engine tabs:

• SUBTRACTIVE SYNTH
• SAMPLE ENGINE
• ADDITIVE SYNTH

A pad's mode is the tab that is lit. Clicking an engine tab changes what the pad plays, immediately. Each pad remembers the settings of all three engines, so you can switch back and forth. Rules to remember:

• A pad in SAMPLE mode with no sample loaded plays its subtractive synth instead.
• An ADDITIVE pad needs a bank of partials. A new pad has a built-in 10-partial bell-like default bank.
• The CONVERT TO ADDITIVE button (next to it, visible while the pad plays the subtractive synth) rebuilds the subtractive sound as an additive synth: a measured bank of partials you can then edit, shape and morph (4.3 explains the analysis).
• The BAKE TO SAMPLE button (top right of the editor, visible when the pad is not already a sample) turns a synth pad into a sample. After a bake the pad is in SAMPLE mode, and BACK TO SYNTH appears.

The editor has two windows below the tabs:

1. The engine window (the tab you chose).
2. PAD CONTROLS (the final stage, right column).

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2. SAMPLE ENGINE

Use the sample engine for recorded sounds, for pads that must be light on the CPU, and for baked synth sounds. The sampler is the best engine for live playing.

2.1 Loading and sources

Trap: loading a file does not reset the sample envelope. A pad whose sampler envelope has SUSTAIN at 0 will fade the new sample away after about one DECAY time. If a loaded sample sounds cut short, set SUSTAIN to 1.00.

2.2 Crop, trim, normalize, reverse, random

The waveform window (canvas) shows the sample with two cyan crop markers.

2.3 Envelope, filter, pitch

There is no sample-pitch slider. Pitch comes from OVERALL PITCH in PAD CONTROLS (section 5). For samples it changes the playback speed, so +12 semitones plays the sample twice as fast and half as long.

Velocity sets the peak level of the envelope.

2.4 Conversion buttons

Both subtractive conversions overwrite OSC 1 to OSC 3 level and type, NOISE 1 and NOISE 2 settings, the main ADSR, the resonant filter and the drive. They do not reset the shaping HP and LP, or the PAD CONTROLS window.

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3. SUBTRACTIVE SYNTH

3.1 Signal flow

 OSC 1 --+   (wave -> pitch glide START -> PITCH END over PITCH DECAY
 OSC 2 --+    -> own TONE DECAY envelope -> own PAN)
 OSC 3 --+
         +--> SUM --> MAIN ADSR --> SHAPING HP --> SHAPING LP
 NOISE 1-+    (if all five levels add up to more than 1.8 the sum is scaled down to 1.8)
 NOISE 2-+   (type -> HP -> LP -> own ATTACK / RELEASE envelope -> own PAN)

 FM stage (optional): any of the five sources ticked in the FM matrix leave the SUM and bend the pitch
 of one extra CARRIER oscillator instead; the carrier joins the SUM (section 3.8)

 --> RESONANT FILTER (always in the chain; lowpass in the editor; cutoff scales with velocity)
 --> DRIVE (algorithm, amount, wet/dry mix)
 --> PAD CONTROLS: FILTER (off/LP/HP) -> DRIVE / OD -> ATTACK fade
 --> pan -> PAD VOLUME -> master mix
                       \-> SEND 1..2 -> reverb / delay

Velocity affects three things on a subtractive pad: source level, resonant filter cutoff (soft hits are darker, hard hits brighter, scale 0.35 to 1.85) and the depth of the pitch drop.

3.2 Layout of the SUBTRACTIVE SYNTH tab

Top row: RECIPE CATEGORY drop-down, CHAOS slider, RANDOMIZE SUB SYNTH button. Below it, seven module tabs:

OSC 1 (PRIMARY), OSC 2 (LAYER), OSC 3 (ACCENT), NOISE 1 (BODY), NOISE 2 (METALLIC), FM SYNTH, SUM & SHAPING.

The old five-channel mixer strip is hidden. Its level, pan and MUTE controls now appear as the first three controls of each source tab (LEVEL, PAN, MUTE; the button reads MUTED while the source is silent).

3.3 Oscillators (OSC 1, OSC 2, OSC 3)

Each oscillator has the same controls. A source with LEVEL below 0.005 is not created at all.

Waveforms (names as shown in the drop-down):

The three cluster types follow the oscillator's pitch drop like any other wave (all their oscillators move together) and, ticked into the FM matrix, they make strong inharmonic modulators. They are also the quickest way to metal when you send them to the FM stage (3.8).

(The code also knows twin_t_snare, a dual-resonance snare body. It is not in the drop-down; kit designs can use it.)

The decay rule (important). Every decay time is the time to fall about 80 dB (to silence), and these envelopes multiply: each oscillator's TONE DECAY, each noise RELEASE, and the main ADSR DECAY all apply at the same time. The time you actually hear to fall 40 dB (t40) is therefore roughly half of the stated time, and the main ADSR shortens it further:

t40 = 0.5 / (1/TONE DECAY + 1/ADSR DECAY)

To hit a target t40, solve for the source decay: TONE DECAY = 1 / (0.5/t40 - 1/ADSR DECAY). Set ADSR DECAY at least as long as your longest source, and ADSR SUSTAIN to 0.

3.4 Noise generators (NOISE 1, NOISE 2)

Sizzle is white noise chopped into random 1 to 7 ms grains of different loudness and tilted towards the highs. Steady noise sounds flat and hissy; sizzle has the restless, glittering surface of a real cymbal or hat (its level flutters by about 1 to 3 dB, real cymbals by 0.6 to 2.6 dB). Use it as the second noise, quieter than the first, with a high SHAPING HP.

| HP CUTOFF (HZ) | High-pass on the noise. Keep it below LP CUTOFF; together they make a band-pass. | 20-12000 / 50-15000 | 20 / 1500 |

| LP CUTOFF (HZ) | Low-pass on the noise. | 100-20000 | 3500 / 12000 |

| PRE-ADSR ATTACK | Fade-in of the noise burst. | 0 to 0.5 s (minimum used is 1 ms) | 0.002 |

| PRE-ADSR RELEASE | Decay of the burst, to about -80 dB. | 0.005 to 2.0 s | 0.15 / 0.08 |

The noise buffers are fixed (the same noise on every hit), so hits are repeatable.

3.5 SUM & SHAPING

Envelopes run by themselves. There is no note-off for a drum hit. The main ADSR fires: attack, (hidden hold, normally 0), decay down to the sustain level, a 20 ms pause at that level, then the release fade. With SUSTAIN at 0 the release is already silent.

Rules that catch people out:

1. The resonant filter is always in the chain and its neutral setting is a 4.5 kHz low-pass with Q 1.5. Hats, claps and cymbals sound dull and quiet until RESONANT CUTOFF is at 20000 and FILTER RESONANCE (Q) is about 0.7. The editor has no filter-type switch, so the resonant filter is a low-pass for any pad you edit by hand.
2. Recipes (RECIPE CATEGORY) and RANDOMIZE set a drive amount but leave DRIVE MIX at 0, so they add no distortion. To hear drive, raise DRIVE MIX.
3. Recipes leave the ADSR and resonant filter as they were. Check them after changing category.
4. DRIVE ALGORITHM can show blank after a recipe that used the names "tube", "tape", "overdrive" or "foldback". Those all behave as Regular Distortion.
5. For kicks use DRIVE ALGORITHM = Regular or Compression + Distortion with SHAPING HP at 24 to 28 Hz, to keep DC offset out.
6. If all source levels add up to more than 1.8 the engine scales them down, so raising one level can make others quieter.

3.6 RECIPE CATEGORY, CHAOS, RANDOMIZE SUB SYNTH

RECIPE CATEGORY (34 categories): Kick, Snare, Hi-Hat, Crash Cymbal, Ride Cymbal, China Cymbal, Clap, Tom, Wood Block, Rim Shot, Bell, Swoosh, Stomp, 8-bit Snare/Cymbal/Hat, Impact Sound, UFO Sound, Drum Fill, Drive-By, Gunshot, Sword Swoosh, Sword Clank, Stab Sound, Whip, Gong, Chimes, Explosion, Page Turn, Fake Electric Car, Transition, Hovering, Bird Chirps, Metal Clang, 8-bit Cymbal, 8-bit Hat.

Choosing one loads that category's starting patch into the pad's oscillators and noises and sets the FX sends to 0. It replaces OSC 3 and NOISE 2 levels, but it does not touch the pad name, the ADSR, the filters, or PAD CONTROLS other than the sends.

Example starting patches (from the code): Kick = sine 240 to 46 Hz over 32 ms, tone decay 0.38 s, plus triangle knock and sub sine, plus pink noise click. Snare = triangle 310 to 185 Hz, sine 330 Hz and 440 Hz overtones, white noise high-passed at 2.1 kHz. Hi-Hat = three squares near 3.8, 5.9 and 8.2 kHz plus white and metallic noise. Tom = sine 220 to 110 Hz over 65 ms, decay 0.48 s.

CHAOS (0 to 100 percent, default 25): how far RANDOMIZE strays. 0 keeps close to genre rules, 100 is experimental. It is the same value as the UNIQ slider in the top bar.

RANDOMIZE SUB SYNTH: reloads the pad's category recipe and then randomizes the oscillators, noises, resonant filter, the pad volume, pan, and FX sends within ranges that suit that category. Kick and Stomp categories (and pads 1 and 2, or any pad named KICK or SUB) always get 0 on both sends. Randomizing never turns drive on. A pad in SAMPLE mode keeps its sample and gets a randomized sampler setting instead.

3.7 Recipes for typical sounds

These are starting points calculated from the engine rules. They have not been auditioned. For every recipe, set in SUM & SHAPING: ADSR SUSTAIN 0, RESONANT CUTOFF 20000, FILTER RESONANCE (Q) 0.7, unless noted. Unlisted levels are 0. Unlisted values stay at the neutral defaults.

808 kick (t40 about 0.4 s)

909 kick (t40 about 0.24 s)

909 snare (t40 about 0.14 s)

Closed hat (808 style)

Clap

Tom (sine)

OSC 1: Sine, LEVEL 1.0, PITCH DECAY 0.05, TONE DECAY 0.9. NOISE 1: Pink, LEVEL 0.15, HP CUTOFF 1000, LP CUTOFF 3500, PRE-ADSR RELEASE 0.02 (stick). ADSR DECAY 0.8 (t40 about 0.2 s). Lower toms get longer decays.

Cowbell: OSC 1 Square 540 to 540, OSC 2 Square 800 to 800, both TONE DECAY 0.35, ADSR DECAY 0.5, SHAPING HP 400, SHAPING LP 6000.

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3.7a Recipe: a better cymbal

Cymbals and hats are the hardest drum sounds to synthesise, because they are made of many unrelated (inharmonic) vibrations plus a restless noise wash. The standard methods, and what this synth offers for each:

The built-in Crash Cymbal and Ride Cymbal categories (RECIPE CATEGORY) use these: for the crash a Modal Plate (510 Hz, level 0.53) with a quiet Metal Cluster (380 Hz) and Shimmer Cluster (875 Hz), white noise (HP 2750) and Sizzle (HP 5000, level 0.2), ADSR DECAY 2.7, SHAPING HP 2900, RESONANT CUTOFF 20000. The recipe was found by trying 600 variants against 17 factory crash recordings: it matches their decay, brightness and band balance better (score 65 against 61 for the old recipe, on a 100-point scale where one recording against another typically reaches 70 to 85).

3.8 FM SYNTH (the FM stage)

The FM SYNTH tab sits after the two noise generators and before the ADSR. It adds one carrier oscillator whose pitch can be bent (frequency modulation) by any of the five sources: OSC 1, OSC 2, OSC 3, NOISE 1 and NOISE 2. It is off when a pad is created or a kit is loaded; the tab shows a dot (FM SYNTH ●) while it is on.

How it works:

1. Tick FM STAGE ON (sub-fm-enable).
2. In the matrix SEND INTO FM (sub-fm-in-1 to sub-fm-in-5: OSC 1, OSC 2, OSC 3, NOISE 1, NOISE 2) tick the sources that should act as modulators. A ticked source is taken out of the normal sum and bends the carrier instead, in mono (its PAN no longer applies). Its own LEVEL sets how strongly it bends the carrier (there are no extra volume faders in the matrix), and its pitch, drop and tone envelope shape the modulation. Unticked sources play as normal, so you can keep a noise burst or a layer outside the FM.
3. The carrier follows OSC 1's pitch curve (START FREQ, PITCH END, PITCH DECAY, TUNE) multiplied by CARRIER RATIO, even when OSC 1 itself is muted or sent into the matrix. It joins the sum with the other sources, then goes through the ADSR, filters, drive and PAD CONTROLS like any other source.

Tips: a sine OSC 2 at a simple ratio to OSC 1 (for example OSC 1 at 130 Hz, OSC 2 at 260 Hz) gives classic bell and tom tones; raise FM INDEX for metal and clangs. Sending NOISE 1 into the matrix gives noisy, rattling FM. Sending OSC 1 itself into the matrix makes the carrier modulate itself with the same pitch curve. FM adds one oscillator and two gain stages per hit (about double the offline render time of a plain pad, still tiny). The FM settings are saved with the pad, work with BAKE TO SAMPLE and CONVERT TO ADDITIVE, and are not touched by the additive tab.

4. ADDITIVE SYNTH (new in v10.2)

4.1 What additive synthesis is

An additive pad builds its sound by adding many plain sine waves, called partials. Each partial has its own frequency, level and decay time. A bell, a tom or a drum body is a handful of partials that fade at different speeds. Because you draw each partial's level yourself, you can reshape the spectrum of a sound directly: darker, hollower, more metallic, longer.

The engine has three parts:

• Bank A: the pad's own partials (the bars you edit).
• Shaping sliders: non-destructive spectral tools applied on top of the stored partials every time the pad plays.
• Layer B (MORPH): a second set of partials copied from any other pad, blended with A during each hit.

Two numbers describe every partial:

• f0: the bank's fundamental frequency. It is the first partial that is at least 30 percent as loud as the loudest one.
• Harmonic ratio r = freq / f0. A partial at r = 2.00 is the second harmonic. A partial more than 0.15 away from a whole number is "inharmonic" (metal, bell). The editor labels bars with their ratio.

What additive synthesis is good at (the sounds this tab is for, which the subtractive synth cannot make as well):

• Struck metal, glass, wood and bells. These have partials at non-whole ratios that each die at their own speed. Series presets give the real ratios of an FM bell, tubular bell, vibraphone and marimba bars, a singing bowl, a gong, a gamelan metallophone and a cymbal cluster.
• Living, beating tones. Two partials a few cents apart beat slowly. SHIMMER adds such twins; SCATTER detunes every partial a little. Both come from the additive method (per-partial tuning) and cost nothing in sound quality.
• Evolving and swelling sounds. BLOOM makes high partials enter later; DECAY TILT makes the highs die first or last; MORPH LAYER B changes the whole spectrum during the hit.
• Surgical spectral editing. Odd or even harmonics only, a formant bump, comb notches, shelves: all act on harmonic numbers, so they stay correct when the pitch changes.
• Resynthesis. CONVERT FROM SAMPLE and CONVERT TO ADDITIVE turn any sound into editable partials, then freeze, stretch, darken or blend it.
• Zaps, drops and risers. PITCH DIVE glides every partial at once, like a sweep.

Limits: it needs many oscillators (live hits use up to 32, extra partials play only when you BAKE), and it is weak at dense noise: add the NOISE (RESIDUAL) layer or print the pad to the sampler.

Partials are always kept sorted by frequency, and every tool works on the real ratio, never on the list position. (So ODD/EVEN really means odd and even harmonics, even if the bank has gaps.)

The pad's pitch comes from the bank itself. To retune a pad, use OVERALL PITCH in PAD CONTROLS (plus or minus 24 semitones). There is no f0 slider. A pad can hold up to 128 partials per bank.

4.2 Top rows of the ADDITIVE SYNTH tab

4.3 Converting a sample: what is estimated

Click CONVERT FROM SAMPLE (or CONVERT SAMPLE TO ADDITIVE SYNTH on the sample tab). The analysis, step by step:

1. The cropped part of the sample is mixed to mono. Set the crop first with AUTO-TRIM.
2. The analysis starts where the signal first reaches 10 percent of its peak (minus 1 ms).
3. Which partials. A long spectrum (8192 points) of the first moment is searched for peaks between 25 Hz and the lower of 20 kHz or 0.45 of the sample rate. A peak must be above -60 dB relative to the strongest and be a local maximum. Peaks closer than 1.2 bins are merged. The loudest N peaks (N is the partial-count drop-down) are kept, with a refined frequency. Only the first window of the sound defines the partial list.
4. Level and decay of each partial. The partial's level is followed over time with short windows (2048 points, or 4096 when the lowest partial is below 90 Hz). A straight line is fitted to the level in dB over the first part of the decay (the part that stays within about 35 dB of the peak). The line gives the starting level (a partial's level is the extrapolated level at time zero, scaled so the loudest is 1.0) and the decay time (time to fall 60 dB, limited to 0.02 to 8 s). If there are fewer than three usable points, or the partial does not fall, its decay is set to the sample length (at most 3 s).
5. Attack. The 1 ms RMS envelope gives the time from 10 to 90 percent of the peak, limited to 0.5 to 30 ms. It is written to the ATTACK (ms) slider.
6. Noise residual. The energy left after removing the peaks (plus or minus 3 bins) is measured in seven bands (60-200, 200-500, 500-1000, 1000-2000, 2000-4000, 4000-8000 Hz and 8 kHz to 16 kHz), each with a level and a decay time. Both conversions (from a sample and from the subtractive synth) set NOISE (RESIDUAL) to 1.00, so the noise part is heard at once; lower the slider to taste. In a test on 80 factory pads this cut the spectral distance to the original from 24 dB to 15 dB (snares, claps, hats and cymbals gain most; kicks and toms were already close).
7. The pad switches to ADDITIVE. The old shaping sliders are not reset.

After a conversion each bar remembers its analysed level, so Alt+click (or the 0 key) can restore it.

4.4 SERIES presets

Choosing a series replaces bank A at once, on the current f0 (110 Hz if the pad has no bank), clears the stored noise residual and keeps layer B. N is the partial-count drop-down.

Decay times of the harmonic series shrink with the harmonic number (about 0.5 to 0.6 s divided by the square root of n).

4.4a SHIMMER, SIZZLE, DIVE & BLOOM

The panel section SHIMMER, SIZZLE, DIVE & BLOOM (METAL, GLASS, CYMBALS, ZAPS) holds six sliders that use what only a bank of independent partials can do. They act on every hit (they are not printed by COMMIT TOOLS, except SCATTER).

Ideas: a bell = FM Bell series + SHIMMER 0.5 + SCATTER 8; a cymbal = Cymbal cluster series (f0 1000 Hz) + SIZZLE 0.5 + DECAY TILT 0.5 + NOISE (RESIDUAL) 0.5; a laser zap = any series + PITCH DIVE +24, DIVE TIME 80; a bowed swell = Organ drawbars + ATTACK 30 ms + BLOOM 0.6. In a test, an additive cymbal cluster reached a similarity score of 58 against 17 reference crashes (the subtractive recipe: 65), but with the sound of a struck metal plate rather than of noise.

4.5 The partial editor (canvas)

The big canvas shows one bar per partial. The upper part shows the level (bar height, linear 0 to 1). The lower purple lane shows the decay of each partial on a log scale from 0.02 to 8 s. Numbers under the bars are the harmonic ratios.

How to read it:

• Bar colour for a harmonic partial moves from cyan to orange-yellow as the ratio rises. Orange bars are inharmonic.
• A white tick on a bar marks its level after shaping and morph tools, so you can see what the sliders do.
• Grey bars are muted (or not soloed). A yellow strip on top marks a solo. A red slash marks a mute.
• Hollow orange outlines are the levels of layer B, matched by position, shown while you edit A.
• The line under the canvas shows: index, frequency in Hz, harmonic number (and "inharmonic"), level in dB, decay in seconds, and [MUTED] or [SOLO].

Mouse

Keyboard (click the canvas first so it has keyboard focus)

Undo. The editor keeps its own 20-step history, used while the canvas has focus (Ctrl+Z, Ctrl+Y) or through the two arrow buttons next to A and B. One drag is one step. Every tool button is one step. It records the partial banks (A and B) and f0. It does not record the shaping sliders or other controls. It is not per pad (see Maintainer notes), so do not undo after you change pad. The project-wide Ctrl+Z is blocked while the canvas has focus. Ctrl+Shift+Z in the canvas is also undo (not redo).

4.6 Tool buttons

The EDIT row: A, B, undo, redo, the tool buttons, and the audition tick box.

COMMIT TOOLS in detail. It always works on bank A. It writes the shaped result into the partials: frequencies after STRETCH and INHARMONICITY, levels after tilt, odd/even, low end, top end, formant, comb and FLOOR, and decays after DURATION and DECAY TILT. Levels are renormalized so the loudest is 1.0. Then it resets TILT, ODD/EVEN, LOW END, TOP END, FORMANT BUMP, COMB, HARMONIC STRETCH, INHARMONICITY, DECAY TILT and DURATION SCALE to neutral. Corner, frequency, width, spacing and shift sliders, PUNCH, SUB-OCTAVE, NOISE, FLOOR and the vibrato stay as they are. Three consequences:

• Muted partials, soloed-out partials and partials below the FLOOR level are deleted for good.
• Partials that lie above 0.45 of the sample rate are dropped.
• The stored "analysed level" of each bar is lost, so Alt+click and the 0 key stop working.

Use COMMIT TOOLS before you want to continue sculpting the sound you hear, and before you copy the pad into another pad's layer B (which reads the shaped result anyway).

4.7 Shaping sliders

These sliders act on both layer A and layer B while the pad plays. Let r be the harmonic ratio of a partial and f its frequency. Amounts are in dB unless stated.

SPECTRAL SHAPING (ODD / EVEN, LOW END, TOP END, FORMANT, COMB, STRETCH)

TIME, LEVEL & NOISE

The pad's overall loudness is normalized automatically (a sum of the partial levels around -4 dBFS peak). Boosting one partial changes the balance more than it raises the volume. Use PAD VOLUME to set the final level.

The "after-shaping" order for each partial: level shaping in dB (tilt, odd/even, low end, top end, formant, comb) then frequency changes (stretch, then inharmonicity), then decay changes (duration, decay tilt). Partials under 20 Hz or above 0.45 of the sample rate are dropped. Then the FLOOR removes quiet partials, and the survivors are sorted loudest-times-longest first for the oscillator cap.

4.8 MORPH LAYER B (copy a tone from another pad and blend)

Layer B is a second bank of partials copied from another pad. During every hit, A and B are blended.

Cross-fade mode. A fades out and B fades in with equal-power curves while the blend goes from START to END over the RAMP TIME. A bank that is not heard (blend near 0 or 1 at both ends) is not played, to save oscillators.

Glide mode. Each partial of A is paired with the nearest partial of B (within one third of an octave). The paired partial slides in frequency, level and decay from A to B over the ramp time. Unpaired partials fade in or out. Glide uses plain sines (the PHASE setting does not apply). It gives a pitch-gliding sound, such as a kick that turns into a tom.

COMMIT BLEND → A in detail. At the MORPH END amount m, A and B partials are paired by pitch (within one third of an octave). Paired partials get frequency and level blended geometrically (in the log domain) and decay blended in a straight line. Unpaired A partials are kept at (1 - m) of their level. Unpaired B partials are added at m of their level.

4.9 CPU cost rules

Additive sound costs one oscillator per partial per hit, plus extras. The engine protects the clock with these limits:

The ~N osc/hit badge is the estimate: the number of partials that survive FLOOR (A plus B when the morph is active), limited to 32 and plus 1 for the sub-octave. It turns amber at 32 or more. If more partials exist than the live cap, it adds "(n partials, capped live)". Everything beyond the cap is skipped live. BAKE it to hear all of them.

4.10 Workflow: design in additive, then BAKE to the sampler

The additive engine is for designing. The sampler is for playing. Work like this:

1. Convert a sample or pick a series preset.
2. Shape it with the bars and sliders until it sounds right (use COMMIT TOOLS to keep going).
3. Click BAKE TO SAMPLE (top right of the editor). The pad renders one hit offline, with up to 96 partials and the full shaping, trims the silent tail (below about -52 dB), and switches to SAMPLE mode. The render length follows the longest partial (at least 1 s, at most 6 s).
4. The baked pad is a normal sample pad: ADSR, filter, crop, PAD CONTROLS and sends all work, and it costs very little CPU.

What the buttons do:

Why baked pads ignore additive edits. After BAKE the pad plays a recorded sample, not the partials. The partial bars, shaping sliders and morph settings are still stored, but nothing reads them until you press BACK TO SYNTH. The orange note "THIS PAD IS BAKED TO A SAMPLE" reminds you. To use new edits you can either un-bake, edit, and bake again, or keep editing the sample.

One more difference: OVERALL PITCH on a baked pad changes the playback speed (the sound gets shorter when raised). On a live additive pad it only transposes the partials.

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5. PAD CONTROLS (the final stage window)

The right-hand window under the engine. It works for all three engines (and for the looper pad). Two columns:

Signal order in this window: engine sound, FILTER, DRIVE / OD, ATTACK, then pan, then PAD VOLUME. The sends are taken after pan and volume, so a quieter pad also sends less. The effect type of each channel (1 reverb, 2 delay) is set in the 2 AUX FX BAYS tab. Only two shared effect channels exist. The send labels and meaning follow the bay setup.

When the looper pad (17) is selected, the same controls (except ATTACK and RELEASE) act on the loop player.

Factory kits start with both sends at 0 (dry). RANDOMIZE can set sends on non-kick pads.

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6. BAKE tools, kits and presets

There is no pad LFO any more: the LFO window, the additive vibrato and the LFO settings inside the factory kits were all removed in build 10.3. (Only the effect bays' own chorus / phaser / flanger sweep remains.)

6.1 BAKE tools

A baked pad plays at the speaker's own sample rate (1:1, no resampling), with the sample ADSR set to ATTACK 1 ms, DECAY 0.05 s, SUSTAIN 1.00, RELEASE 0.05 s. Its tail is trimmed at about -52 dB with an 8 ms fade-out. BAKE KIT keeps the pad's final filter, drive and attack live on the pad; PERFORM mode instead prints them into the sample.

Un-baking restores the previous sample, crop, pitch and ADSR that the pad had before the bake (for kit pads: the reference or printed sample it held). Normalize and reverse you did on the baked sample are lost. Baked state survives saving a project (the pad remembers which engine it came from).

PERFORM mode (F9) bakes all synth pads for you; it is described in the performance chapter.

6.2 Kits and presets

KIT ONLY (top bar) loads a drum kit onto all 16 pads without changing the sequencer patterns. It is not a full set: MASTER FULL SET also loads patterns, FX bays and tempo notes; SEQUENCE STYLE loads patterns only.

• 42 kits in the KIT ONLY drop-down, in two groups: Vintage Machines (20) and Genre & Modern (22).
• 10 newer designed kits, in a third group, New designed kits (10): Studio Acoustic Kit, Latin Percussion Rack, Blip Arcade 8-Bit, Casio SK-1 Toy Kit, Dream Trance 96, 80s Stab Hit Kit, Combat Foley FX, Found Object Percussion, Synth Boss Kit, Crushed Distortion Machine.
• Several kits also exist under a second name (for example "Techno" = TR-909, "Pop" = LinnDrum LM-2, "Rock" = Alesis SR-16 Studio, "Trip Hop", "Lo-Fi", "Synthwave"). The 52 designed kits have 62 names in total.

Every kit was designed on the subtractive synth by measurement and reference (the designs are in tools/sounddesign/designs). The pad roles of a kit match the pad positions: pads 1 to 16 stay kick, kick, snare, snare, clap, rim, closed hat, open hat, three toms, crash, ride, two percussion, and an FX sound, so the sequencer patterns work on every kit. Every pad in a kit is meant to sound different from its siblings.

KITS LOAD AS: SAMPLES / SYNTHS (SETTINGS > CPU; remembered, applies to the next kit you load)

Kit loading starts every pad from the neutral synth defaults, so a kit never depends on the kit loaded before it. Loading a kit never changes tempo or swing; the PRESET button in the top bar can restore the kit's own tempo.

Hardware families. Each kit carries a family tag:

• Family 1, analog synthesis: TR-808, TR-909, TR-606, CR-78, DR-110, KR-55, Minipops 7, Simmons SDS-V, Moog DFAM, and most genre kits (techno, synthwave, trap, drill, dub, cinematic, hardstyle, IDM, and the new kits).
• Family 2, digital samplers: LinnDrum, DMX, SP-1200, MPC60, MPC3000, Yamaha RX5, Alesis SR-16, Casio RZ-1, Drumulator, Roland R-8, and some genre kits (boom bap, chillhop, trip hop, jungle, afrobeat, neo-soul, UK garage, French house).

For the shipped (designed) kits, every pad is first a synth pad; the family tag matters only for older reference sounds (the sample info line and the converters use it when a pad has no sample). The tag itself does not change how the kit plays (unverified beyond that).

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7. Sound-design cookbook and glossary

All values are starting points, not auditioned. After setting them, adjust by ear.

7.1 Eight recipes

1. Tight synth kick (subtractive). OSC 1 Sine, LEVEL 1.0, START FREQ 220, PITCH END 50, PITCH DECAY 0.03, TONE DECAY 0.6. ADSR DECAY 0.7, SUSTAIN 0, SHAPING HP 26, RESONANT CUTOFF 20000, Q 0.7. Add NOISE 1 White at LEVEL 0.1, HP CUTOFF 2000, PRE-ADSR RELEASE 0.01 for a click.

2. Rim click or wood block (subtractive). OSC 1 Triangle, LEVEL 0.8, START FREQ 600, PITCH END 340, PITCH DECAY 0.01, TONE DECAY 0.06. OSC 3 Square, LEVEL 0.18, START FREQ 1200, PITCH END 1200, TONE DECAY 0.03. NOISE 1 White at LEVEL 0.4, HP CUTOFF 3600, PRE-ADSR RELEASE 0.03. ADSR DECAY 0.1.

3. Struck bell (additive). Series presets: Bell (inharmonic). PAD CONTROLS OVERALL PITCH +12 ST for a higher bell. DURATION SCALE 1.5, DECAY TILT 0.5, PUNCH 0.6, ATTACK (ms) 0.5, SUB-OCTAVE 0. For a more metallic bell, set INHARMONICITY 0.2.

4. Metallic hat (additive). Series presets: Glass (inharmonic). INHARMONICITY 0.8, TOP END +9 dB with TOP END CORNER 6, DECAY TILT 0.8, SUB-OCTAVE 0, ATTACK (ms) 0.5, NOISE (RESIDUAL) 0.3. DURATION SCALE 0.3 for a closed hat, 1.2 for an open hat. Then BAKE TO SAMPLE.

5. Hollow tom (additive). Series presets: Saw (1/n), then ODD / EVEN HARMONICS 0.1 (odd harmonics stand out), SPECTRAL TILT -0.5, DURATION SCALE 0.5, SUB-OCTAVE 0.6, PUNCH 0.7. OVERALL PITCH -5 ST.

6. Snare from a sample (additive). Load a snare, AUTO-TRIM, choose 32 partials, CONVERT FROM SAMPLE. Raise NOISE (RESIDUAL) to 0.6 to bring the snares back, PUNCH 0.7, SUB-OCTAVE 0. Use TOP END +6 dB for more snap, DURATION SCALE 0.8 for a shorter tail. COMMIT TOOLS, then BAKE TO SAMPLE.

7. Kick that mutates into a tom (morph). On a converted kick pad (A), COPY TONE → B from a tom pad, tick align pitch off, mode Glide (partials slide), MORPH START 0, MORPH END 1, MORPH RAMP TIME 0.15, MORPH CURVE -0.4. Then BAKE TO SAMPLE so it plays cheaply.

8. Vowel-like stab (additive). Series presets: Saw (1/n). FORMANT BUMP +12 dB, FORMANT FREQUENCY 800, FORMANT WIDTH (Q) 3, COMB (NOTCHES) 0.4 with COMB SPACING 3. DURATION SCALE 0.6. Sweep COMB SHIFT slowly while you listen.

7.2 Glossary

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Maintainer notes

This section lists where each part of the chapter comes from, so you can update it when features change. Re-check these files after any change.

Known quirks seen while writing this chapter (verify, then fix the app or this text)

1. SEND TO ADDITIVE. The button reads CONVERT SAMPLE TO ADDITIVE SYNTH but resets to "SEND TO ADDITIVE" after a click. There is no button called SEND TO SUBTRACTIVE; the two subtractive buttons are CONVERT SAMPLE TO SUBTRACTIVE SYNTH and MATCH SUBTRACTIVE SYNTH TO SAMPLE, which run the same matcher.
2. Hat choke is described in PROJECT_STATE.md as pads 6 and 7 choking pad 8; the code chokes by id (pad 7 chokes pad 8) or by the words CLOSED and OPEN in the pad names.
3. Subtractive recipes write drive types "tube", "tape", "overdrive" and "foldback" that the DRIVE ALGORITHM drop-down does not contain (the drop-down then shows blank). They behave as Regular.
4. Sample preset "Ride Cymbal Bell" is not matched by any ride branch in loadSyntheticSamplePreset and falls to the generic voice.
5. Resonant filter type (lowpass, bandpass, highpass) cannot be changed in the editor; only kit data sets it.
6. Hidden controls: fundLock (additive), adsrHold (subtractive) and sample pitch (samplePitch, set by RANDOM) have no control in the UI.
7. NORM normalizes channels separately; REVERSE reverses the whole buffer, not the crop.
8. Version stamps. PROJECT_STATE.md is at v9.4.0 in its header while its sections go to v10.1; this chapter assumes v10.2 for the additive v2 panel.
9. In additive-ui.js the draw gesture uses an odd interpolation helper (b2); the behaviour (straight fill between sampled bars) matches the description above, but check it again if the gesture code is changed.

AXIOM 16-P User Manual - Part 3: Sequencer, Loops and Effects

This part covers the sequencer (steps, bars, recording, tools), the 16 pattern slots and live cueing, swing and tempo-synced features, the 8-slot loop slicer with the looper pad (Track 17), and the two AUX FX channels (reverb and delay) with the master bus. Manual for app build 10.3. The pads and sound engines are in Part 2. The top bar, menus, projects, MIDI and PERFORM mode are in Part 1.

Control names are written exactly as they appear on screen. "(unverified)" marks statements that could not be confirmed in the code. Ranges and defaults come from index.html and the JavaScript files named in the Maintainer notes.

Contents

1. The sequencer
2. Pattern slots, styles and song mode
3. Swing, groove, tempo and sync
4. The 8-slot loop slicer and the looper pad
5. The 2 AUX FX channels and the master bus
6. Worked examples
7. Known quirks and troubleshooting
8. Maintainer notes

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1. The sequencer

1.1 How it is organised

You edit one track at a time in the active step row at the bottom of the screen. Select a track by pressing its pad (or the orange looper pad for Track 17), or by clicking its name in the 17-row grid (1.8). The badge above the row shows the selected track, for example PAD 1: 909 PUNCH KICK or LOOP TRACK // name, and MEASURE 1 / 8.

The step LEDs under the label STEP // BEAT move with the playhead. They only light while the bar you are looking at is the bar that is playing. Press the BAR buttons to follow the playhead. The BAR and STEP displays in the top bar always show the real position.

1.2 Transport and keys

Keys 1-4, Q-R, A-F and Z-V play pads 1-16 (see Part 2). Keys 5 and 6 are the two AUX FX trigger pads (5.6). Every pad lights when its sound plays, from any pattern, bar, MIDI note or recording (also while the engine sheds load); the orange looper pad lights when the loop starts. SETTINGS > PAD LIGHTS: OFF turns the lights off.

1.3 Step buttons

The active step row has 16 numbered buttons. Steps 1-4 are red, 5-8 orange, 9-12 yellow and 13-16 white, so you can count beats at a glance.

A step badge under the number shows a hit modifier (TRIP 2, FLAM and so on, see 1.6). In the 17-row grid a small cyan dot marks steps that have a modifier. While MIDI learn is active, clicking a step maps it to a MIDI control instead of painting it (Part 1).

New steps have velocity 100, micro-timing 0, pan 0 and modifier Normal. Switching a step off keeps its velocity, pan and modifier; they come back when you switch it on again.

1.4 Step inspector

Open it from ⚙ EDIT or by right-clicking a step. Its title reads INSPECT: <track name> (Bar n, Step m). Changes apply at once. Close it with the ✕ button.

The ⚙ EDIT button's mouse-over text lists what the inspector has: velocity, micro-timing, pan, chance, step modifier and MIDI note. The step inspector is not a learn target, but the ⚙ EDIT buttons themselves can be learned (5.3).

1.5 The parameter lane (VEL / PAN / MICRO / MOD)

The strip under the step row has 16 cells, one per step of the shown bar, and four tabs.

Press and drag across the cells to draw values. The bottom of a cell is the minimum and the top is the maximum. Cells of steps that are switched off are dimmed; you can still draw values into them, and drawing does not switch the step on. The tab you chose stays selected when you change tracks or bars.

1.6 Step modifiers

The inspector lists nine hit types. The lane and the step badge show them in short form.

The lane cycles in this order: Normal, FLM, R2, R3, BRST, GHST, OFF, HOLD, SKIP, then Normal again.

Hit letters in the factory pattern files. The pattern data files that build the 32 sequence styles (js/pattern-data-*.js) write steps as text. You never type these, but they explain what styles contain. Digits 1-9 set velocity (1 = 30 up to 9 = 127). Letters set a modifier:

A . or - is a rest.

1.7 Track length, polyrhythm and skip

Every track has an internal length of 1-16 steps (default 16). A shorter track repeats inside each bar, which gives polyrhythms. No control on screen sets this length; it comes from loaded projects and pasted patterns (unverified whether any other route sets it). The factory styles do not use it.

A step set to SKIP, when it is switched on, plays nothing and pushes that track one step ahead of the master grid. It stays out of phase until you press STOP or SYNC GRID. SYNC GRID (in the pattern tool row) moves every track back to the master grid.

1.8 Bars, pattern length and the 17-row grid

Pressing a pattern slot loads that pattern's own length into LIMIT (section 2). Changing LIMIT while the pattern plays takes effect at the next wrap.

1.9 Mute, solo and audition

Mute and solo apply to all patterns, not to one slot, and they are saved in projects.

1.10 Live recording (REC)

Press REC to arm recording. If the sequencer is stopped it starts. Pads you press (mouse, keys or MIDI) while it plays are written into the current pattern at the playhead. REC lights while armed. It refuses to arm while the active pattern is locked.

Press the gear button next to REC for the setup window, SEQUENCER LIVE RECORD SETUP.

How recording behaves:

• A hit goes to the nearest 16th step. A hit slightly before the downbeat lands on that downbeat, with a negative micro-timing when quantize is below 100%.
• The velocity comes from where you press the pad (higher on the pad is louder), from the key (fixed velocity 100) or from the MIDI velocity.
• Overdub keeps the step's existing modifier. Overwrite sets the modifier back to Normal.
• Overwrite also clears every other active step on every track as the playhead passes it, unless you hit that step in the same pass. Tracks that are muted (or not soloed) are skipped, so solo the track you want to replace to protect the rest.
• If you start recording with REC alone, the current mode, quantize strength and pattern slot are used. Defaults are Overdub and 100%.
• The recording is stored in the active slot immediately.

1.11 Track tools

The TRACK TOOLS row works on the selected track and the shown bar only (COPY TO ALL BARS writes to all 8). They are refused while the pattern is locked.

1.12 Bar tools and pattern generator

The COPY, PASTE, DUPE and CLEAR buttons briefly show a check mark and a past-tense word (DUPE shows LAST BAR on bar 8), then return to their labels.

1.13 Pattern tools

These work on the whole active pattern (all 17 tracks, all 8 bars).

A locked pattern refuses: recording (REC will not arm), PASTE PATTERN into it, DUPE PATTERN onto it, and CLEAR PATTERN. It does not stop editing steps by hand, CLEAR or CLEAR ACTIVE PAD, or loading a style or set (which replaces all 16 slots). Locks are saved in projects.

1.14 MIDI export of a pattern

EXPORT MIDI downloads a Type 0 Standard MIDI file named axiom-pattern-N.mid (N = active slot number). It contains the pattern as it is currently loaded.

• Length: the LIMIT bars, 480 PPQN, channel 10, tempo = the current BPM.
• Every active step becomes a note with its velocity. Steps set to SKIP or Note Off are left out.
• Micro-timing, swing, pan and modifiers are not written (a ratchet is one note).
• Pads map to General MIDI drum notes: pad 1 = 36, 2 = 34, 3 = 38, 4 = 40, 5 = 39, 6 = 37, 7 = 42, 8 = 46, 9 = 41, 10 = 45, 11 = 48, 12 = 49, 13 = 51, 14 = 75, 15 = 56, 16 = 52, Track 17 = 54. These notes import back onto the same pads through MIDI import.
• Mute and solo are ignored.

1.15 The sequencer in PERFORM mode

PERFORM mode keeps the pattern slots, ◀ PREV / NEXT ▶ and the BAR buttons, MUTE, SOLO, ▶ AUDITION and the step row with its playhead. It hides the pattern tools row, LIMIT, STYLE and RANDOM PATTERN, the bar tools, TRACK TOOLS, the parameter lane, ⚙ EDIT, CHAIN and the 17-row grid. Switch back to FULL (F9) to use them.

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2. Pattern slots, styles and song mode

2.1 The PATTERNS: row

The row PATTERNS: has 16 buttons. Each shows its number and a role name (Intro, Verse 1, Chorus 2, Fill and so on). Mouse-over text reads Song 1: Verse 1 (4 bars - click to cue).

What a slot stores: all 17 tracks x 128 steps (active state, velocity, micro-timing, modifier, pan, MIDI note), the pattern length in bars, the role name, a name, and the tempo, swing and groove the pattern was written with. It does not store pad sounds, effects, mute/solo or the loop audio.

When you switch away from a slot, your edits to it are saved into it first. Slots are saved in projects (FILE > SAVE PROJECT). Autosave covers them too (Part 1).

2.2 Switching patterns

A double-click is two clicks on the same button within 350 ms. Clicking another slot replaces the cue. A cue that is waiting is lost if you load a style or a set.

Button states

Example: pattern 2 is 4 bars long and plays at bar 3. A single click on slot 5 makes the change at the end of bar 4. A double-click on slot 5 changes at the start of bar 4, and slot 5 starts from its bar 1.

2.3 Song structure and sequence styles

The SEQUENCE STYLE drop-down in the preset bar (and the STYLE: drop-down in the sequencer) offers 32 styles: from TR-808 Classic Electro and TR-909 Peak Techno to Hyperpop Speed Glitch and Miami Bass Booty Shake. Each style is two short songs written by hand:

• Slots 1-8 are Song A. Slots 9-16 are Song B.
• Each song has the sections Intro, Verse 1, Verse 2, a fill or pre-chorus, Chorus 1, Chorus 2, a breakdown or bridge, and Outro. The names change with the genre.
• Each section has its own length of 1-4 bars and its own tempo and swing. Example, TR-808 Classic Electro song A: Intro 2 bars, Verse 1 4, Verse 2 4, Pre-Chorus 2, Chorus 1 4, Chorus 2 4, Breakdown 4, Outro 2.
• The patterns use pads 1-16 only; the loop track is empty.

Loading a style replaces all 16 slots and selects slot 1. Edits in the old slots are lost unless you saved a project first. It does not change the pad sounds and it does not change the tempo. The style's tempo and swing are offered through PRESET (2.5).

2.4 Master Full Sets

The MASTER FULL SET drop-down (★ in the top bar) has 32 sets. Each combines one drum kit, one style (16 patterns), the two AUX FX channels and the master volume and master compressor setting of the kit. Pick one to hear a complete song set at once. It loads kit and style, selects slot 1, and remembers the set's tempo and swing for the PRESET button. The kit drop-down is KIT ONLY (sounds only, patterns stay).

A kit or set overwrites both AUX FX channels (their effects, parameters and return levels), which may surprise you if you tuned them. The reverb in channel 1 follows the first-run rule in 5.2: a new user keeps Light Room until a reverb has been picked.

2.5 The tempo rule

Loading never changes your tempo or swing. This holds for kits, full sets, sequence styles, pattern slots, pasted patterns and imported MIDI files. Each load only remembers the tempo it was saved with.

• The PRESET button (top bar, shows the saved BPM, for example PRESET 128) is greyed out until something has been loaded. It turns amber when the saved tempo or swing differs from the current one.
• Press PRESET to apply the saved tempo and swing (and groove type). A message confirms it.
• A tag next to the tempo shows what set the tempo last: EXT CLOCK, TAP, PRESET, PROJECT or LOOP MATCH.
• Loading a project restores the project's own tempo (tag PROJECT).
• Start-up tempo is 120.

The BPM figures written in the SET drop-down are fixed text and can differ from the tempo the set really applies. For example DMX Old School Hip Hop is listed as 96 BPM, while its pattern data applies 108. The PRESET button shows the real value.

2.6 Song mode (CHAIN)

The CHAIN: OFF / CHAIN: ON button (next to MUTE and SOLO) turns on song mode. On the last step of each pattern, the next slot is cued: slot 1 then 2 and so on through 16, then back to 1. Each pattern plays for its own LIMIT length. A slot you cued yourself takes priority over the chain. Press the button again to stop chaining; the current pattern then loops.

To play a whole style as a song, pick the style, turn CHAIN ON and press PLAY.

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3. Swing, groove, tempo and sync

3.1 Swing and groove type

The SWING slider (50-75%, default 50% = straight) and the groove drop-down next to it are in the top bar.

The swing percentage is the share of a note pair given to its first note. 66% gives a triplet feel on 16th swing. Swing moves the sound of the notes and the metronome. Micro-timing is added on top. MIDI clock out stays straight.

3.2 Tempo

Without decimals, the tempo is rounded to a whole number. Typing, clock follow and loop matching can give fractional tempos.

3.3 Tempo-synced controls

These controls lock to the tempo. The divisions are the same everywhere.

Synced values follow tempo changes. An effect channel is rebuilt about half a second after the tempo settles, which also keeps un-synced delay times at their fraction of a beat.

3.4 External MIDI clock

SETTINGS > MIDI CLOCK SYNC:

Only the first MIDI input is used for clock. The details of choosing a device are in Part 1. When a MIDI output is selected, the app also sends clock, Start and Stop to it (not while it follows a master).

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4. The 8-slot loop slicer and the looper pad

The loop slicer plays audio loops in time with the sequencer. It is Track 17. Open it with the 8-SLOT LOOP SLICER tab, or by pressing the orange looper pad. It is only available in FULL mode from the tab; in PERFORM mode use the looper pad (4.8).

4.1 The slots

The left column lists 8 loop slots. Click a slot to make it the active loop for the slicer, the preview and Track 17. Each slot shows its number, name and BPM.

• Slots 1-4 hold generated drum breaks: Amen Funk Break (130 BPM), Electro 808 Groove (124), Downtempo Trip (85) and Techno 4-on-Floor (132). Each is 2 bars long, but their BARS value starts at 1, so AUTO-PLAY MEASURE restarts them every bar until you set BARS to 2 under MANUAL OVERRIDE.
• Slots 5-8 are empty ("Loop Slot 5" ... "Loop Slot 8").
• Loop audio is not saved in projects. Load your files again after reopening the app (7.1).

4.2 Loading audio

The slot is named after the file (the first 16 characters). The app then reads the tempo:

• WAV files with ACID or stretch information give the exact BPM, beat count and time signature.
• Other files get a guess. The app tries loop lengths of 4, 8, 16, 32, 64 or 128 beats and keeps the one whose tempo is between 60 and 180 BPM and closest to 120.

If the guess is wrong, use MANUAL OVERRIDE (4.5). Loading also detects slices (4.3).

4.3 Waveform, slices and playback modes

A trigger plays the loop once. It does not repeat by itself. A new trigger cuts the loop that is playing and starts again from the beginning. To loop it, put a step on Track 17 at the start of each repeat, or use AUTO-PLAY MEASURE (4.6).

Pre-stretch. In PERFORM mode, the stretch is calculated once in the background and played from one sound instead of hundreds of small grains. This is much lighter on the CPU. The result is kept per slot and rebuilt about half a second after a tempo change. The first hit after a tempo change may play at a slightly different pitch while the new version is being prepared. When the loop is already at the project tempo it plays unchanged. If OVERALL PITCH is not 0, the app uses the live (heavier) stretch instead.

4.4 Matching the tempo

⚡ MATCH BPM TO LOOP sets the project tempo to the active loop's BPM (the manual BPM when MANUAL OVERRIDE is on). The tag next to the tempo then reads LOOP MATCH. The speed buttons are not taken into account. This is the only place a loop changes the tempo by itself.

4.5 Manual BPM, bars and time signature

Tick MANUAL OVERRIDE to correct the guessed values for the active slot. The three fields next to it then unlock.

Settings are kept per slot.

4.6 AUTO-PLAY MEASURE and speed

4.7 Convert a slice to a pad

CONVERT SLICE: drop-down (Pad 1 to Pad 16) plus EXPORT SLICE TO PAD. The selected slice is copied into the chosen pad as a sample (the pad name becomes SL_<slot>_<slice>), with a very short fade at the end. The pad switches to its sampler, its crop is reset, and it is selected for editing. The button reads ✓ Exported! for a moment. The old sound of that pad is replaced.

4.8 The orange looper pad (Track 17)

The orange pad under the 16 pads reads LOOP: AMEN BREAK (the name does not follow the active slot; unverified) and LOOP TOOL PAD. It has the badge LP and the number 17.

In PERFORM mode. The pad stays, and the 8-SLOT LOOP SLICER tab is hidden. Press the orange pad to open the slicer panel. Then:

1. Pick a slot and play it with ▶ PLAY LOOP or by pressing the pad.
2. Set the pattern step row to Track 17: pressing the pad does that. Put a step on step 1 for a loop that restarts every pattern, or switch AUTO-PLAY MEASURE: ON.
3. Use MATCH BPM TO LOOP to put the project on the loop's tempo.
4. Loading audio, MANUAL OVERRIDE and EXPORT SLICE TO PAD work as in FULL mode.

4.9 Loop mixer controls

The loop has no mixer of its own. While Track 17 is selected, the PAD CONTROLS window (in the PAD SOUND ENGINE tab) controls the loop instead of a pad. (This was read from the code; unverified in a browser.)

Loop mixer values are not saved in projects.

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5. The 2 AUX FX channels and the master bus

Open the 2 AUX FX BAYS tab. The app has two shared effect channels: AUX 1 = reverb and AUX 2 = delay. (Older versions had four; sessions saved with four keep only the first two sends.) The terms "bay" and "channel" mean the same thing below.

5.1 Signal flow

pad (volume, pan) ──┬── dry ─────────────────────────────┐
                    └── SEND 1 / 2 ► AUX 1 / 2 ► RETURN ──┤
loop (Track 17)  ── same, with its own SEND 1-2 ──────────┤
                                                          ▼
                       master bus: compressor ► MASTER VOL ► limiter ► soft clipper ► speakers

1. Each pad has two SEND knobs, SEND 1 (REV) and SEND 2 (DLY), in PAD CONTROLS. Each knob sends a copy of the pad, after its volume and pan, to the matching channel. The dry sound is not reduced. Sends default to 0 (fully dry).
2. Each bay is an effect (5.3). Its output is the wet signal only.
3. The bay's RETURN LEVEL sets how loud the wet signal is, then a fixed trim of 0.8 is applied (not adjustable).
4. The returns join the dry pads in the master bus (5.8).

Because the channels are parallel (send) effects, they add a processed copy next to the dry sound. They do not replace it. To change the dry sound itself use the pad's own filter and drive.

The labels of SEND n, the FX n return faders and the live trigger pads follow what each channel is set to (REV, DLY; a session that holds another effect shows MOD, DYN or DRV).

5.2 The bay controls

Default channels at start-up: AUX 1 Reverbs / Light Room, AUX 2 Delays / Ping-Pong. A parameter change rebuilds the effect after a very short pause; you may hear a tail reset when you drag a knob.

First-run reverb rule. A new user starts with the lightest reverb, Light Room, and kits and sets that carry a reverb are loaded with Light Room instead of their own. This protects slow computers. Once you pick a reverb in channel 1 yourself, or open a session that was saved with a different reverb, the browser remembers it (localStorage key axiom.reverbPicked) and kits may bring their own reverb again. Kits and full sets still replace the delay, the parameters and the return levels of both channels.

The engine still contains Modulation, Dynamics / EQ and Drive / Harmonics effects. The UI no longer offers them (the category list is limited to the channel's role); they can only appear through an older saved session, or through kit data that names them (unverified whether any kit does). They are described in 5.3 for that case.

5.3 Algorithms and what PARAM 1-4 mean

- means the parameter is not used by that algorithm.

Reverbs (channel 1). All five use a light algorithmic reverb (damped delay lines and diffusers per side). The algorithm sets the room size and tail length factor. PARAM 2 works as a brightness control: higher is brighter, lower is darker.

Delays (channel 2). The delay times are fractions of a beat, so they follow the BPM even with TEMPO SYNC set to Free (Hz). With TEMPO SYNC on, the time is one division.

The longest delay is about 2.9 s. Slow tempos with large divisions are capped at that.

The three families below are not selectable in the UI any more (see 5.2); they are listed for sessions that still hold them.

Modulation. The effect is the modulated copy; the phaser and flanger also include the dry signal inside the bay. With TEMPO SYNC the LFO rate is one cycle per division (capped at 40 Hz).

Dynamics / EQ. In a send bay these process a parallel copy.

Drive / Harmonics. The distortions are fully wet; the exciter includes the dry sound.

5.4 Return levels

There are two places to set the same level:

• MASTER AUX RETURNS (two sliders FX 1 and FX 2, range 0-1).
• RETURN LEVEL (range 0-1.5), for the selected bay.

They set the same bay output. Moving one does not move the other, so they can show different positions (7.1).

5.5 Tempo sync

The TEMPO SYNC drop-down of a channel locks the delay time (delay effects) to a division of the BPM (see 3.3). The choice is per channel and is saved in projects. Reverbs ignore it (so does every non-delay effect except chorus, phaser and flanger, which lock their LFO rate).

5.6 Live trigger pads (gate)

Under the bay controls, AUX FX LIVE TRIGGER PADS (KEYS 5-6) hold two pads: FX 1 [KEY 5] and FX 2 [KEY 6], each labelled with the channel's algorithm.

The gate sits after the effect, so the effect keeps running while closed: opening the reverb channel brings in the tail built up so far. Settings are saved in projects. The sliders are shown at 10 ms and 200 ms; a bay that you have not touched starts with 15 ms and 150 ms (unverified).

5.7 The master bus

All pads, the loop and the aux returns meet in masterIn, then:

The metronome click goes straight to the output and bypasses this chain.

An older master reverb and tape delay exist in the engine but nothing feeds them; they have no controls.

5.8 PERFORM mode and the bays

In PERFORM mode a channel that no pad sends to (all sends 0) and that has TRIGGER MODE off is disconnected 3 seconds after its last send goes quiet, so it costs no CPU. A reverb tail can still ring out. When you raise a send the bay reconnects at once. In FULL mode all bays stay connected.

The disconnect looks only at pad sends. A bay fed only by the looper (Track 17) SEND is treated as unused (read from the code; unverified in a browser). Give the bay a tiny pad send or leave PERFORM mode if the loop's effect goes silent.

Separately, in any mode, if the engine falls behind repeatedly (2 or more stalls or overloads within 10 seconds), the reverb channel (and any modulation effect from an old session) is muted for 8 seconds. The LOAD badge in the top bar then adds FX MUTED. The drums keep time. See Part 1.

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6. Worked examples

6.1 Build a 4-bar beat from scratch

1. Press STOP, then pattern slot 16 (or any slot you do not need). Press CLEAR PATTERN and confirm. (If the slot holds a style pattern you want to keep, pick another slot first.)
2. Set LIMIT: to 4 Bars.
3. Press BAR 1. Press pad 1 (the kick) so the step row shows Track 1.
4. Click steps 1, 5, 9 and 13. You hear the kick on each beat.
5. Select pad 3 (snare). Click steps 5 and 13 (beats 2 and 4).
6. Select pad 7 (closed hat). Set EUCLIDEAN: to 8 hits and press FILL for eight even hats. (Or drag across steps 1, 3, 5, 7... with the mouse.)
7. Press PLAY. Bar 1 loops until you have more bars.
8. With the kick selected, press the COPY button (bar tools), press BAR 2, then PASTE. Do the same for the snare and hat (select each pad, BAR 1, COPY, BAR 2, PASTE). A quicker way is DUPE (it works on the selected track): on BAR 1 press DUPE, and you land on bar 2 with bar 1 copied; press DUPE again to fill bar 3, and so on.
9. On bar 4, vary it: select the snare, click the MOD tab, click step 16 until the cell reads R2 (a roll). Click a few extra kick steps.
10. Open the VEL tab and drag across the hat cells to draw accents: tall on the beats, short in between.
11. Press the lock button (LOCK / UNLOCK) if you want it protected from accidental record, paste or clear.
12. Save with FILE > SAVE PROJECT.

6.2 Switch patterns live with single and double click

1. Pick a style in the STYLE (SEQUENCE STYLE) drop-down. Slot 1 loads. Press PLAY.
2. While the Intro plays, single-click slot 2 (Verse 1). Its button pulses. When the Intro has played its last bar, Verse 1 starts. You never get a half-finished pattern.
3. To jump sooner, double-click slot 5 (Chorus 1) while Verse 1 is in its second bar. The button gets an orange outline and pulses faster. At the next bar line Chorus 1 starts from its first bar.
4. To let the app run the arrangement, press CHAIN: OFF so it reads CHAIN: ON. Slots then play in order. Your own clicks still win.
5. Remember: loading another style replaces all 16 slots.

6.3 Add reverb to a snare with a send

1. Check the bay: open the 2 AUX FX BAYS tab and look at AUX 1 (default Reverbs / Light Room; pick Room or Hall for a bigger sound). Set PARAM 1 about 0.4 for a short tail, PARAM 2 about 0.6. Set RETURN LEVEL to 0.8 or so.
2. Press the PAD SOUND ENGINE tab. Press the snare pad (pad 3) to select it.
3. In PAD CONTROLS raise SEND 1 (REV) to about 0.25. The snare keeps its dry sound and a reverb copy is added.
4. Press PLAY and adjust SEND 1 for the wet amount, RETURN LEVEL for the whole reverb, PARAM 1 for the tail length.
5. For a gated, rhythmic splash instead, press TRIGGER MODE in the AUX bay tab so it reads ON. The reverb is then silent until you hold the FX 1 pad (or key 5), and it opens and closes with ATT (MS) and REL (MS).
6. Turn SEND 2 (DLY) back to 0 if you hear the delay too.

6.4 Record a loop and match the tempo

1. Open the 8-SLOT LOOP SLICER tab and click an empty slot, for example slot 5.
2. Press + LOAD AUDIO and choose your loop file. It loads, gets a guessed BPM and is cut into slices.
3. Look at the BPM shown in the slot and in the BPM: field. If you know the real tempo, tick MANUAL OVERRIDE, type the BPM and set BARS to the length of the loop (for example 2).
4. Press ⚡ MATCH BPM TO LOOP. The tempo changes to the loop's tempo and the tag reads LOOP MATCH. (The tempo never changes without this press or another tempo control.)
5. Press MODE: Time-Synced Stretch (default) and press ▶ PLAY LOOP to hear it at the project tempo.
6. To use it in the beat, press the orange looper pad, then click step 1 in the step row. Set LIMIT to the loop length in bars. The loop restarts at step 1 of each pattern pass. Or press AUTO-PLAY MEASURE: OFF so it reads ON, and the loop retriggers itself every BARS bars.
7. Press PLAY. Change the BPM in the top bar and the loop follows it; it stays in time.
8. To use one hit as a drum sound, press the waveform at that hit (the slice turns orange), choose a target in CONVERT SLICE: and press EXPORT SLICE TO PAD.

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7. Known quirks and troubleshooting

7.1 Known quirks

These are labels or behaviours that differ from what you might expect. Each was checked in the code at the time of writing.

7.2 Troubleshooting

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8. Maintainer notes

Update this list when files or functions are renamed. Line numbers are not recorded because the files change often.

When any of these change, re-check: the algorithm table (5.3) against rebuildFXChain, the modifier table (1.6) against _executeStepModifier, the quirks table (7.1) against the code, and the SET drop-down tempos against js/pattern-data-*.js.

04 - Version 11: EDIT / PERFORM, rendering, LFOs, loops and the new engines

This part describes how the app works since build 11 and replaces the older "BAKE" wording in parts 2 and 3. Where an older sentence in parts 1-3 talks about baking, PERFORM baking all synth pads or the sequencer being visible while editing, read this part instead.

1. Two sides: EDIT and PERFORM

The two buttons EDIT and PERFORM at the top of the window (keys F1 / F2; F8 / F9 switch the pad view and sound view) change what the whole app is for.

Everything PERFORM does not need is switched off to save processor time: the synth engines, the engine workers, the cached renders, the FX 3 and FX 4 bays, the idle effect bays and (unless you switch it on) the loop engine. Going back to EDIT switches it all on again. Your EDIT effects are kept in the project and come back.

Why this split? PERFORM has to be ultra smooth: it only plays recorded samples, with two light effects. All the heavy sound design (synth engines, LFOs, final filter, big reverbs) happens in EDIT and is rendered into the sample of the pad.

2. Rendering: the SAMPLER is the PERFORM voice

Every pad has a sampler. The sampler's sample is what PERFORM plays. A pad that never got a sample is rendered automatically when you enter PERFORM.

Rules to know:

• The tabs of the new engines (PHYSICAL MODEL, WAVESHAPER, WAVETABLE, VOCODER) and the subtractive / additive tabs are EDIT only. In PERFORM the pad reverts to its sample; in EDIT it plays the engine again, so you can go back and forth and listen to each engine with the same pad.
• The sampler keeps the final filter etc. in its own sample: it never applies them twice.
• Rendering a pad does not change which engine tab it is on.

3. Two LFOs per pad (LFO window)

Each pad has two LFOs, and every slider of the pad editor can be a target (about 170 targets: oscillators, noise, filters, FM, envelope, the additive shaping sliders, the final stage, the pad volume / pan / tune, the four new engines, and even the other LFO's rate and depth).

Pitch, filter cutoffs, resonances, levels, pan, the FM index and the final filter move continuously inside the hit; every other parameter is moved once per hit (the value for that hit). All LFO movement is in the render.

4. The four send effects

There are four effect bays. Bays 1 and 2 are the reverb and delay. FX 3 and FX 4 are the two further effect channels (EDIT only). Each pad has four send sliders. In PERFORM only the reverb and delay exist. To get a heavier reverb into PERFORM, use PRINT SEND FX or render with + SEND FX.

5. Loops and loop sets

Render the sequence to a sample: in PERFORM, the loop buttons render the active pattern (a number of bars) to a stereo sample with the sample voices, the chosen effects and a seamless tail. The result goes to the looper, where you can audition it in the loop tool.

Convert all sequences to loops: renders all pattern slots one after the other into the loop set.

Loop set: 16 loops with names. The LOOP SET tab (EDIT, deck) lists them, lets you rename, render, load, delete, save (.axloops file) and load a loop set.

Playing the loops: the old PADS | LOOPS switch has become the DJ / LOOP mode (top bar button, F10): two decks play the 16 loops (see part 7). In PERFORM the complete sequencer stays under the pads, with the two looper pads and the RENDER SEQUENCE... button (the active sequence into a loop, all sequences into all loops, or to a WAV file).

6. The new engines (EDIT tabs)

Every engine tab has RANDOMIZE and DEFAULTS buttons, all sliders have a tooltip and can be targeted by the LFOs, the pad's final filter / drive / attack / release apply to every engine, and every engine is rendered to the sampler like the others. All of them are light on the processor: a hit is calculated once per setting and then played from memory.

6.1 PHYSICAL MODEL

A struck or plucked object calculated from physics.

Good for toms, congas, bongos, wood blocks, claves, bells, plates, gongs, tuned percussion, plucked and struck strings. A short cymbal: MODE SET plate, spread 0.6, noise exciter, damping 0.2.

6.2 WAVESHAPER (non-linear / distortion synthesis)

A simple tone is pushed through a curve that folds, clips or bends it into rich harmonics. INPUT chooses what is shaped: Own tone, or the sound of any other source (sampler, subtractive, additive, physical model, wavetable, the looper). When another source is chosen, its tab and (for the looper) its pad light up while you are on this pad, so you always see what feeds the shaper.

• If the sampler is the input, rendering replaces the pad's sample with the shaped version. Rendering again shapes the original again, so nothing builds up. The previous sample stays in PREVIOUS SAMPLES.
• The shaper replaces only the pad's sample, not the looper's loops (when the looper is the input it is only read).
• The pad remembers the last five samples (see rendering above).

Controls: OWN TONE (oscillator sine / triangle / saw / square / noise, pitch start and end, pitch drop time, attack, decay); THE SHAPER (SHAPE: soft clip, hard clip, wavefolder, sine fold, Chebyshev harmonics, asymmetric, phase distortion, bit / rate crusher; DRIVE; DRIVE FOLLOWS LEVEL = bright attack, clean tail; BIAS; fold THRESHOLD; the HARMONIC 2-6 levels for the Chebyshev shape; PHASE DISTORTION; BITS; RATE DIVIDER); OUTPUT (TONE, DRY / WET, LEVEL).

6.3 WAVETABLE

Two tables play together and are mixed. Each table has 16 morphing waveforms. 25 tables made for drums, percussion and effects: kick body, sub thump, tom, snare shell and wires, wood block, metal bell, glass, metallic hat noise, periodic noise, soft noise, zap, laser, formant sweep, vocal "ah", FM bell, FM metal, saw stack, pulse width morph, organ, pluck, click, digital harsh, chaos, hollow pipe and analog thump.

Controls: TABLES (TABLE A / B, POSITION, SWEEP of the position during the hit, SWEEP TIME, MIX A / B, PITCH RATIO B, DETUNE B); PITCH & ENVELOPE (pitch start / end / drop time, attack, decay, ENVELOPE SNAP); SOUND SHAPING (HARD SYNC, WARP, FM of B into A, UNISON, UNISON DETUNE, SUB, NOISE, BIT DEPTH, LEVEL).

6.4 VOCODER ("reverse additive")

An ordinary vocoder listens to a voice and shapes a carrier. This one listens to the ADDITIVE synth: each of its strongest partials (at most 18) becomes one filter band, the partial's level and decay open and close that band, and the bank of filters shapes another sound, the carrier. You design the spectrum on the ADDITIVE tab (use the button EDIT THE BANDS) and listen to it here.

• CARRIER: saw (plays the chord), pulse, white noise, pink noise, or the sound of another engine, the sampler, the looper, or the waveshaper. A sample or loop carrier is repeated if it is shorter than the longest band.
• MODE: Vocoder (only the bands are heard) or EQ sculpt (the carrier is heard in full and each partial lifts or cuts its band).
• Controls: NUMBER OF BANDS, BAND WIDTH (Q), EQ RANGE, FORMANT SHIFT (all bands up or down), BAND STRETCH, LEVEL SLOPE, DECAY SCALE, BAND ATTACK, CARRIER BLEED; HIGH-PASS 30 Hz and LOW-PASS 18 kHz cut before the bands.
• MIDI IN: tick "MIDI IN PLAYS THIS PAD", select this pad with the vocoder open, and play notes on a MIDI keyboard. The note sets the pitch (relative to the ROOT NOTE) and the chord strip is built on it. No external audio is needed.

7. CHORD strip (all engines)

Under the engine tabs: CHORD on / off, four note drop-downs (semitones above the pad's pitch, or off) and TRANSPOSE (the main key, -24 to +24). When CHORD is on, one hit plays all chosen notes together (their level is balanced), with every engine. The chord is part of the render.

8. Kits in v11

The first 15 factory kits were redone in a second round with the rule authenticity first: analog machines (TR-808, 909, 606, CR-78, KR-55, DFAM, SDS-V) keep their subtractive circuit models, and sampler-era machines (LinnDrum, DMX, SP-1200, MPC60, MPC3000, SR-16, R-8) are emulated with the engines, or converted from a library sample into a synth (additive / subtractive), and only as a last resort play a library recording (at most 3 per kit; the list is LIBRARY_SAMPLES_USED.md). EDIT plays the engine, PERFORM plays the rendered sample. AI Kit 01 is at the top of the kit list (and as the set AI Kit 01 Groove), and SFX Designer Kit is the 16th kit: sixteen sound effects (impacts, risers, zaps, clangs, gongs, chimes, whooshes) made with all engines and the LFOs.

Maintainer notes (v11)

• Source files: js/layout.js (EDIT / PERFORM), js/modulation.js (LFO), js/fx-print.js (print send FX, perform effects), js/loopset.js (loop sets), js/engine-dsp.js (the sound calculation of the four engines, also run in Web Workers), js/engines.js (the engines in the app: panels, links, chord, MIDI in).
• Lab tests for these features: tools/sounddesign/out/t_s1.js (edit / perform / render), t_lfo.js, t_s3.js (effects), t_s4.js (loops), t_dsp.js (engine calculation), t_eng.js (engines in the app). Run with python tools/sounddesign/sd.py eval <file>.
• Designing kits with the engines: tools/sounddesign/SOUND_DESIGN_V11.md.

05 - Engine parameter reference (v11)

Every slider and drop-down of the four new engines, as it appears on screen. Defaults are the values after DEFAULTS. All sliders can be targets of the LFOs.

PHYSICAL MODEL

MODEL

EXCITER (WHAT HITS IT)

BODY (HOW IT VIBRATES)

SKIN, WIRES & STEREO

WAVESHAPER

INPUT

OWN TONE

THE SHAPER

OUTPUT

WAVETABLE

TABLES

PITCH & ENVELOPE

SOUND SHAPING

VOCODER (REVERSE ADDITIVE)

CARRIER (THE SOUND THAT IS SHAPED)

BANDS (FROM THE ADDITIVE TAB)

CUTS & OUTPUT

MIDI IN

CHORD strip

06 - Added controls (v11 checklist)

Controls added or relabelled in version 11 with the text shown on screen. Their behaviour is described in part 4.

07 - Version 11.3: two loopers, storage folder, render sequence, DJ / LOOP

This part describes what was added after part 4. It replaces part 4's PADS | LOOPS switch: loop playing is now the DJ / LOOP mode.

1. The three sections of the app

The three big buttons at the left of the top bar choose the section. The app opens in PERFORM (the pads, with the kit built in the background).

The workflow: build pads and kits in EDIT; play and sequence in PERFORM (RENDER SEQUENCE turns the sequences into loops); DJ the loops on the two decks in DJ / LOOP, and export packs.

2. Two loopers (A and B)

The loop tool exists twice. Looper A is sequencer row 17, Looper B is row 18. Each has its own 8 loop slots, level, pan, FX sends and on / off switch, and each can hold a short loop or a whole song.

• Looper pads: two pads, the same size as the drum pads, under the 4x4 matrix: LP A and LP B. Next to each pad is its LOOP A: ON / LOOP B: ON switch (off frees its CPU and silences its sequencer row). Tap a pad to select that looper (the loop rack then edits it) and play it. While the sequencer is playing, the loop starts on the next bar line (the pad pulses until it does); with the sequencer stopped it starts at once.
• 8-SLOT LOOP SLICER tab: the buttons LOOPER A | LOOPER B at the top choose which looper the rack, the waveform and the PAD CONTROLS (volume, pan, sends, final filter) edit.
• THIS SLOT IS A loop / song: Loop follows the project tempo (time-stretched). Song plays once as it is, with no stretching: load a whole mp3 / wav / aiff and use the looper as a player.
• RENDER AT TEMPO: stretches the loop to the project tempo once, offline, and keeps the result as a plain sample: afterwards it plays with no stretching and no CPU cost. UNDO RENDER brings the original back.
• Sequencer row 18 is the extra row for Looper B (EXPAND 18 ROWS shows all rows). Patterns made before the second looper simply have an empty row 18.

3. Tempo syncs: straight, dotted, triplet, bars

Every tempo-synced time (the delay / modulation TEMPO SYNC of the FX bays, the LFO TEMPO SYNC) offers 1/2, 1/4, 1/8, 1/16, 1/32 as straight, dotted and triplet note values (written 1/8 dotted, 1/8 triplet), plus 1/64, 1/128 (FX) and 1, 2 and 4 bars. A dotted note lasts one and a half times, a triplet two thirds, of the straight note.

4. Editing while you play

• The page you are working on stays open when you press a pad: the 4 AUX FX BAYS page, the LOOP SET page and so on only hand over to the pad editor when you were on the pad editor itself (or the loop rack). So you can edit an effect and keep triggering pads.
• The RENDER TO SAMPLER and RENDER KIT buttons are repeated at the top of every synth page (subtractive, additive, physical model, waveshaper, wavetable, vocoder), with the state "SAMPLE = THIS ENGINE" / "EDITED SINCE RENDER". (The old "BAKE PAD WAV" item of the FILE menu is a separate command.)
• The CHORD (VOCODER) strip (4 notes + transpose) is part of the VOCODER page: the chord belongs to the vocoder. (Factory pads that were built with a chord on another engine keep playing it.)

5. Sequencer toolbar

The toolbar at the top of the sequencer (patterns, bars, STYLE and RANDOM PATTERN) stays in view while the track rows scroll underneath. EXPAND 18 ROWS shows the 16 pads and the two loopers.

6. RENDER SEQUENCE

The RENDER SEQUENCE... button (in the sequencer area in PERFORM) opens a window:

1. Render the active sequence as a loop, into the loop you choose in a drop-down of the 16 loops (a loop that has a sound is replaced).
2. Render all sequences to all loops: discards all 16 loops and replaces them with the 16 sequences rendered in order (empty sequences leave their loop empty). Asks first.
3. Render to file: the active sequence, or all of them (one file each), as a WAV file (16 or 24 bit), saved into AXIOM Data / renders, a folder you pick, or downloaded. MP3 appears in the list only when an MP3 encoder (lamejs) is added to the app.

The renders use the pads' samples and the FX 1 / FX 2 effects as PERFORM plays them; the tail of the last bar is folded onto the start, so a loop repeats without a gap. The loops are what DJ / LOOP plays.

7. RECORD MIX

FILE > RECORD MIX records everything you hear (pads, loopers, the DJ decks, effects) as a stereo WAV until you click it again (or the red bar). The file is saved in AXIOM Data / renders and also offered as a download.

8. Storage: the app comes without samples

The app folder holds no audio. The factory kits are rendered from their synth settings the first time you use them (about a second per kit) and kept; the next time the kit loads instantly. A kit whose settings change is rebuilt automatically.

The first time the app starts it asks where to keep its files:

• Choose a folder: a folder called AXIOM Data is made in the folder you pick (Chrome / Edge). It contains kits (the rendered kits), loops, loopsets, sequences, midi (copies of MIDI files you import), renders (rendered sequences, mix recordings) and projects. Copy it together with the app to a thumb drive.
• Use browser storage: nothing to pick; the files live inside this browser.
• Ask me later: browser storage now; ask again from SETTINGS.

SETTINGS > STORAGE FOLDER... changes it later. Move the existing files copies what is there into the new place; switched off, the new place starts empty and the kits are rebuilt there when you use them. After a restart the browser may ask for one click to let the app use the folder again (a button appears: CLICK TO RECONNECT THE AXIOM DATA FOLDER).

9. DJ / LOOP mode

Open it with the DJ / LOOP button (third of the big mode buttons, top left) or F10. The pads and the sequencer switch off (the clock only keeps time) and the DJ rig opens: two turntables (deck A left, deck B right, which are the two loopers), the list of the 16 loops between them, and under each deck its 3-band EQ with kill buttons and its level fader with a meter. The crossfader is under the loop list, between the decks. The 16 loops are the ones you made with RENDER SEQUENCE (or loaded from files); loops that are not loops (songs) work too. Only one loop plays on a deck at a time: starting or loading another one replaces it, and a loop started by a sequencer row or a looper pad takes the deck over.

Loading a deck. Click the deck's platter (or its name) to select the deck, then click a loop pad: that loop loads into the selected deck. The pad shows which deck holds it (A / B). Selecting a deck does not play it: the deck's own PLAY button (also MIDI learnable) starts it, so a deck can be chosen from a controller without being triggered. LOAD opens an audio file (wav, mp3, aiff...) straight into the deck as a song; drop a file on a deck for the same. With the box STORE FILES IN A PAD ticked, a loaded file is also kept in a free loop pad.

While the clock runs (the transport is playing) a started or loaded loop waits for the next bar line. With the transport stopped it starts at once.

EQ and levels (under each deck). HI / MID / LOW knobs with a KILL button each (a true cut), a level fader and a level meter. The crossfader blends the decks; the CURVE in the top bar chooses full (both open in the middle), constant power or hard cut. The EQ and crossfader also shape the loops the sequencer triggers on rows 17 and 18.

Scratch tool. The gear button opens a pop-up with ATTACK, SUSTAIN (the length of the hold), DECAY, RELEASE and DISTANCE, with a drawing of the stroke. The setting stays until you change it. Three preset buttons hold settings: a click recalls one, holding it about a second saves the current setting into it (both scratch buttons use it). A SLIP option keeps the groove in time under the scratch. To scratch with a controller, map a knob or wheel to the platter (JOG: absolute or relative encoder) or map the REV / FWD buttons.

MIDI. Every control of the rig (play, cue, sync, loop pads, EQ, kill, level, crossfader, pitch, scratch buttons, jog) can be learned with MIDI LEARN like any other control; the mappings are kept with the others.

Keyboard (DJ / LOOP only): Q A Z W S control deck A (play, cue, sync, scratch forward, scratch reverse), P L M O K deck B; digits 1-9 and 0 load loops 1-10 into the selected deck; Tab switches the selected deck; [ and ] move the crossfader.

Decks in PERFORM. In pad mode a small DECK A / DECK B button sits next to each looper's switch. It opens a small window with play / stop, the loop list, the three EQ sliders with kill buttons, the level and the crossfader, so the loops can be mixed while you play and sequence.

Limits: the EQ crossovers are steep (24 dB/octave), so a kill leaves about -32 dB right next to a crossover frequency; the tempo of a song is detected roughly (use TAP); the loop length buttons assume 4/4; big songs are not kept in the loop set after a restart.

DJ rig: small controls

| BPM field of deck A | The BPM of the item in deck A (type to correct it). SYNC uses it. |

| BPM field of deck B | The BPM of the item in deck B (type to correct it). SYNC uses it. |

10. EXPORT PACK (the final window)

EXPORT PACK... (top bar of the DJ / LOOP rig, also FILE > EXPORT SAMPLE PACK) makes sample packs from what you built: the 16 loops (one WAV each, with the BPM in the name), the 16 sounds of the kit in the pads (one-shot WAV files and a kit.json with names, levels and pan) and every kit built so far (each factory kit you have opened once). Choose WAV 16 or 24 bit and a ZIP file (download, also kept in AXIOM Data / renders / packs), files in AXIOM Data / renders / packs, or files in a folder you pick.

11. Stereo

Factory kits get a natural stereo image: toms, hats, cymbals, rim and percussion are panned across the field as on a drum kit (kick, snare and bass stay in the middle) and the noisy or metallic sounds (hats, cymbals, claps, rims, effects) are widened with a short, high-passed side signal (the low end stays mono). Loops rendered from a sequence therefore have a real stereo picture. The pad STEREO PAN and the looper PAN work as before.

12. The PERFORM layout

The pads stay big: the sequencer shows the pattern buttons, the bar buttons, STYLE and RANDOM PATTERN, and the 16 steps. The TOOLS button opens the rest (pattern copy / paste / dupe / clear, the track tools, the value lane and EXPAND 18 ROWS). The two looper pads with their on / off switches and DECK buttons are a slim row under the pads.

13. Decks, the transport and CUE

PLAY on a deck starts the main transport when everything has stopped, so one press starts the loops and the clock together. The switch STOP CLOCK WHEN DECKS STOP (top bar of the DJ rig, on by default) makes the transport stop again when the last deck stops and nothing else is playing; switched off, the transport keeps running. A transport you started yourself in PERFORM is never stopped by a deck.

CUE: while a deck plays, CUE stops it and returns to the cue point. Stopped away from the cue point, CUE sets the cue point here. Stopped on the cue point, CUE plays a preview for as long as you hold it (the deck goes back on release); press PLAY while holding CUE to keep playing.

14. Compatibility: Mac, Windows, phone

• Chrome, Edge, Brave (Windows, macOS, Linux): everything works, including Web MIDI (macOS uses CoreMIDI: USB class-compliant devices and network MIDI show up), the audio output choice and the storage folder. This was checked by reading the code, it has not been run on a Mac here.
• Safari (macOS, iOS) and every iPhone browser: sound and the whole app work; there is no Web MIDI, no folder picker and no output choice (Apple does not offer them). Firefox: no Web MIDI.
• Android, Chrome: sound, touch and USB MIDI (with an OTG cable) work; the storage folder is not offered (the browser storage is used).
• Web MIDI needs a secure address: a file, localhost or an https:// address.
• macOS keys: F9 / F10 belong to Mission Control. Use Alt+1 EDIT, Alt+2 PERFORM, Alt+3 DJ / LOOP, Alt+4 COMPACT / FULL.
• Sound card: SETTINGS > SOUND CARD > SAMPLE RATE (AUTO follows the card; 44.1 / 48 / 88.2 / 96 kHz can be forced, reload to apply). SETTINGS > COMPATIBILITY lists what the browser you use lacks.
• UI SIZE (SETTINGS > DISPLAY): on large monitors the whole unit, panels, pads and editing windows, grows together (AUTO), or you fix 100 - 250 %.

15. COMPACT (phone) layout

On a phone, or a small or touch window, the app opens in the COMPACT layout; the COMPACT button next to the mode buttons (and FULL in the compact top bar, and Alt+4) switches on any device. Top: the menu, EDIT | PERFORM | DJ. Below: the page tabs, and 16 big pads that become what the tab says:

• KIT: the 16 drum pads (touch higher on a pad = louder). EDIT: also selects the pad for the sound editor.
• SEQ: the 16 steps of the track (left to right, then the next row down) and the bar; arrows pick the track (including LOOP A / B) and the bar, M / S mute and solo.
• PATTERNS (PERFORM): the 16 pattern presets: tap = next bar, double tap = at once. LOOPS (DJ): the 16 loops: tap loads the selected deck, hold loads the other deck.
• USER: 4 banks (A - D) of 16 pads you set: ASSIGN (or hold a pad) opens the list of about 130 functions: transport, tempo, kit and pattern changes, any pad / step / pattern / loop, loopers, the pad sound (volume, pan, tune, filter, drive, sends), deck play / cue / sync / scratch / level / EQ / kill / crossfader and the modes. A trigger runs when pressed; a switch toggles; a + / - function moves the value in small steps with a tap and runs to its maximum or minimum while you hold it.

Under the pads: PLAY, STOP, REC, TAP, BPM - / +, the two loopers (PERFORM) or the deck buttons (DJ), and the sheet button (EDIT / MORE / MIXER) that opens the bottom sheet: SYNTH, LFO, FINAL, FX, LOOPERS, LOOP SET, TOOLS, 18 ROWS (DJ: MIXER with scratch, EQ, kill, level, pitch and crossfader, FX, LOOP SET, EXPORT). The menu holds the kit, set and style lists, project save / load, render sequence, export pack, record mix, MIDI and storage.

On a phone: serve the folder over https (or localhost) and open it in Chrome; with "Add to Home screen" / "Install app" it runs full screen and keeps working offline after the first visit.

16. The song layout of the 16 patterns (build 11.6)

Every sequence style is now one song of 16 parts, in this order, colour coded on the pattern buttons:

The percussion loops are made to be layered by the two DJ decks over the verse and chorus patterns: in DJ / LOOP mode render them (RENDER SEQUENCE > RENDER ALL) and load them onto a deck while the other deck plays a verse or chorus loop.

FOLLOW. After an intro, fill or the bridge has played through once, the sequencer goes on to the part set for it: by default Long Intro and Short Intro go to Verse 1, Fill 1 to Verse 2, Fill 2 to Verse 3 and the Bridge to Verse 4. The FOLLOW button next to the pattern buttons switches this on or off (off: the part loops until you choose another). GOES TO... opens a small panel where each of the five parts gets its own target (any verse, chorus, bridge, intro or fill). CHAIN plays the song order Long Intro, V1, V2, C1, V3, V4, C2, Bridge, C3 and starts again at Verse 1.

17. Velocity and the pads

The sequencer steps carry a velocity (1-127) and the patterns use it: accents, soft off-beat hats, ghost notes, rising rolls. Each pad can compensate: VELOCITY RESPONSE (PAD CONTROLS) sets how much the velocity matters (100% = full, 0% = every hit equally loud) and VELOCITY CURVE lifts the soft hits (positive) or makes the pad more dynamic (negative). Factory kits give hats, rim and small percussion a slight lift so soft 8th / 16th notes stay audible.

18. Main transport and the decks

Stopping the main transport (STOP or PAUSE) now stops everything: the loopers, the loop set and both DJ decks. The first time you enter DJ / LOOP mode with empty decks, the app renders the Long Intro and Percussion Loop 1 of the current kit and style and loads them on deck A (intro) and deck B (percussion loop), so there is something to play at once.

19. The kits and the pad order (build 11.10)

Every kit lists its 16 pads in the role order below (the same order as the pattern data, so every pattern row plays the right sound in every kit). A pad controller or keyboard plays pad 1 on C1 (note 36), pad 2 on C#1 ... pad 16 on D#2 (note 51); that is the order of the pads, not a General MIDI drum map (section 21 explains how GM notes reach the right pads).

The genre kits were redesigned with the physical-model, waveshaper, wavetable and vocoder engines, and all sounds that are played as 8th or 16th notes (closed and open hat, rim, percussion, ride, crash, sub kick, effect hits) are short and light: closed hats about 50-80 ms, open hats under 300 ms, crashes under 800 ms. Projects saved by builds 11.8 - 11.10 in the short-lived General MIDI pad order are converted back to this order when they are opened.

20. The sample strip and tempo drag (build 11.6)

In PERFORM the pad window shows the sample strip of the selected pad: the waveform of its sample with one rubber-band tool. The two vertical handles set where the sample starts and stops; the two round points on the band set the fade in and the fade out (the band rises from the start to the left point, runs flat, and falls from the right point to the stop). The read-out under the band shows the start and stop in seconds and the fades in milliseconds. The settings are saved with the pad and used at every hit. The strip only repaints while you move a handle, and the waveform is calculated once per sample, so it costs almost no CPU.

The tempo can be dragged: press the big BPM number and move up or down (one BPM per 4 pixels, hold Shift for steps of 0.1). The number box and its arrows stay.

21. MIDI note layout and General MIDI drums (build 11.7)

The 16 pads start on a C: the pad controller profile "General MIDI drum layout" is the default, pad 1 = C1 = note 36, pad 2 = C#1, pad 3 = D1 ... pad 16 = D#2 (note 51), exactly the notes of a General MIDI drum kit. (The note numbers use C3 = 60; Ableton shows them one octave lower.) The ROOT MIDI NOTE of the playable pads and the sequencer steps (steps 1-16 start on E2 = 52, above the pads) can be shifted by octaves in MIDI SETUP; -OCT / +OCT moves the pads up to C2 = 48, etc.

General MIDI drum map (channel 10) as AXIOM reads and writes it. The pad number is the pad that carries that drum role (section 19):

Playing the pad grid from a controller (NOTE MAP "pads in order") puts pad n on note 35 + n, and note 35 (B0) plays the sub kick pad as well; the table above is used by import, export, audition, network notes and the NOTE MAP "General MIDI drums". On export every pad writes the note that means what the pad is (kick 36, sub kick 35, snare 38, snare 2 40, clap 39, rim 37, closed hat 42, open hat 46, low tom 41, mid tom 45, high tom 48, crash 49, ride 51, percussion 1 cowbell 56, percussion 2 tambourine 54, effect splash 55), so a General MIDI module plays the right instrument.

MIDI import (FILE > MIDI IMPORT) uses this table to route a drum part onto the pad roles (you can still change every note in the routing matrix; AUTO-DETECT GM resets it). MIDI export writes each pad as its GM note (the sub kick as 35); the two loopers are written as notes 84 and 85. The same table is used for audition and for notes received over the network sync.

NOTE MAP (MIDI SETUP): "Pads in order from C" (default) plays pad 1, 2, 3 ... from note 36 upwards; "General MIDI drums" plays the pad with the same drum ROLE as the GM note, so a GM drum keyboard or a GM drum track plays kick, snare, toms and hats on the right pads whatever the layout of your controller.

22. NETWORK SYNC (build 11.7)

The SYNC button in the top bar opens the sync window. It connects AXIOM with other AXIOM windows and with any other synth, sampler or sequencer that uses the sync library (docs/SYNC_PROTOCOL.md), so that they play together.

• Windows of the same browser on the same computer need nothing else: switch SYNC on in each and give them the same ROOM name.
• Other devices (laptops, tablets, phones on the same Wi-Fi / network) connect through the AXIOM server: run python axiom_server.py (macOS / Linux: python3), open the printed address on every device, tick OTHER DEVICES (network) and use the same ROOM. The server only forwards messages; it stores nothing.
• Roles. MASTER: this app sets tempo, swing, play / stop and the KEY / SCALE / CHORD for the others. SLAVE: follows the master: tempo and swing at once, start / stop, and the bar position (it starts on the master's next bar line and is kept locked, the window shows the phase error). PEER: only shares notes. The boxes under "A SLAVE FOLLOWS" switch each kind of data on or off.
• Notes. SEND my notes sends every pad hit as a General MIDI drum note; PLAY notes from the others plays incoming drum notes on the pad with that role.
• RESET SYNC forgets the others, measures the clock again and lets a slave lock onto the master's next bar line. COPY LINK (SLAVE) copies a link that opens this app as a slave in the same room; NEW WINDOW AS SLAVE opens one.
• Pressing PLAY on a slave while the master plays waits for the master's next bar line. Stopping a slave by hand keeps it stopped until the master stops and starts again.
• Ableton Link cannot run inside a web page. To follow Ableton Live or a hardware master use SETTINGS > MIDI CLOCK SYNC (FOLLOW CLOCK).

The pad notes always win: a MIDI-learned control that sits on one of the pad notes (36-51, and 35) no longer takes the pad over. The pad plays, the learned mapping is ignored, and the app says which mapping it was (a message when the app starts and in the MIDI monitor). Learn that control again on another note, or use RESET DEFAULT MIDI in MIDI SETUP to clear all learned mappings.

23. Reverb and delay (build 11.9)

FX 1 is the reverb and FX 2 the delay, on both the EDIT and the PERFORM side. They were rebuilt as real studio effects in one light audio-worklet node each (a few percent of one processor core: the old low-load reverb is still in the list as "Light Room"). Moving a knob changes the sound at once and never cuts the tail. They are wet-only returns: the pad SEND (SEND 1 REV / SEND 2 DLY in PAD CONTROLS) sets how much of the pad goes in, the bay's RETURN LEVEL how much comes back.

Reverbs: Plate (default), Studio Hall, Chamber, Cathedral (each is a starting character; every control stays yours): PRE-DELAY, SIZE, DECAY (0.2 - 15 s), DAMPING / HIGH CUT, LOW CUT, DIFFUSION, MODULATION, STEREO WIDTH, EARLY REFLECTIONS. Delays: Stereo Delay (default), Ping-Pong+, Tape Echo: TIME (or TEMPO SYNC), RIGHT TIME (ratio to the left), FEEDBACK, PING-PONG, LOW CUT and HIGH CUT inside the repeats, WOBBLE and WOBBLE RATE, DRIVE (saturation) and STEREO WIDTH; changing the time glides like tape. Where the browser has no AudioWorklet (a page opened over plain http from another device) the older node-based reverb and delay play instead.

Effects that seemed to stick. Two things could silence an effect by themselves and are fixed: (1) the FX trigger gate (TRIGGER MODE on the EDIT side's aux tab) stays closed until a trigger pad / key 5-8 is held, and it was saved with the project and kept in PERFORM, where it cannot be seen: in PERFORM and DJ / LOOP the effects now always pass and the trigger mode only exists on the EDIT side (it is switched back on when you return to EDIT); keys 5-8 no longer fire the FX triggers in PERFORM. (2) The CPU auto-mute switched the reverb out for 8 seconds when the computer stalled: it is now off unless you tick SETTINGS > CPU > FX AUTO-MUTE ON OVERLOAD. A send that is turned up now always connects its effect at once.

24. DJ pads (build 11.9)

In DJ / LOOP mode there are 16 DJ pads: two rows of four under each deck (deck A = pads 1-8, deck B = pads 9-16), looking like the regular pads, with their pad key in the corner. They are a separate set of sample pads for effects and shouts: air horn, siren, laser, rewind, scratch, spin down, "hey!", "yeah!", bass drop, riser, boom, radio tuning, news sting, brass hit, crowd, boing (synthesised by the app: no sound file is shipped or downloaded). They answer to the normal pad keys (1 2 3 4 / Q W E R and A S D F / Z X C V), to MIDI notes 36-51 (pad 1 = C1), to a click or touch and to the compact layout. Your kit is not touched: its pads keep their sounds and play again as soon as you leave DJ / LOOP (the pads only play these samples while DJ / LOOP is active). A new hit of a pad cuts its previous hit; very light on the processor.

Your own sounds: right-click (or hold) a DJ pad, or open DJ PADS... in the DJ top bar: LOAD puts a sound file (wav, mp3, aiff ... up to 12 seconds) into a pad, RESET brings the built-in sound back, LOAD 16 FILES... fills pads 1-16 in file-name order. Your sounds are kept in the AXIOM Data folder (djpads/) and loaded every time.

Keys in DJ / LOOP: because the plain letter keys now play the DJ pads, the deck commands are Shift + letter: Shift+Q / A / Z / W / S = deck A play, cue, sync, scratch forward, reverse; Shift+P / L / M / O / K = deck B; Shift+1 ... 0 load loops 1-10 into the selected deck. Tab and [ ] are unchanged.

25. GRID CONTROLLER: Akai APC Key 25 and Launchpad (build 11.10)

MIDI SETUP > GRID CONTROLLER (AKAI APC / LAUNCHPAD) lights the pad grid of a controller with this app's pads, in the app's colours, and lets you play them: the idea is "hit a grid pad = activate a pattern". Supported: Akai APC Key 25 mk2 (40 RGB pads: the exact colours of the app), APC Key 25 first generation (3 colours: green / red / yellow, blinking = playing or cued; the pad layout is not verified, use LEARN FIRST PAD), Novation Launchpad X (RGB) and, experimental, the 16 pads of a Launchkey MK2 49 (on / off only). I could not test with real hardware: press LIGHT TEST first.

What lights up (tick under THIS APP PUTS ON THE GRID): PATTERNS (the 16 pattern pads, 8 x 2, in the colours of the pattern buttons: verse red, chorus orange, bridge amber, intro and fill yellow, percussion white). A pattern with notes is lit at normal level, an empty one is dim, the playing one is bright, and a pattern you just selected flashes for a moment and then stays bright; a pattern that is cued (waiting for the next bar) keeps blinking until it starts. A tap on a pad cues that pattern, a quick second tap = at the next measure. In DJ / LOOP the 16 pads are the 16 loops and a tap loads the selected deck. STEPS (optional, off by default) shows the 16 steps of the selected track and bar: lit = on, white = the playhead; a tap switches the step.

Placing the blocks. The table WHERE EACH BLOCK STARTS ON THE GRID lists every block (also those of other apps): give each its ROW (1 = top) and COL (1 = left), or order them with the arrows and press PACK IN THIS ORDER (top first), for example the drum patterns on the top two rows, the bass patterns under them, the steps below. RESET PLACES starts again. The PREVIEW shows the grid as the controller shows it (click a cell to press it, handy without a controller).

Connecting. Press CONNECT (the browser asks once for MIDI access with SysEx). The app finds the controller's grid port by name (the second USB MIDI port: Control, MIDIIN2 or MIDI 2); the controller's keyboard keeps going through the normal MIDI input, only the grid port is used here and its pads never play drum notes. DISCONNECT switches the lights off. On an Android phone (Chrome, USB OTG) Web MIDI works the same, but needs a secure page: use adb reverse tcp:8765 tcp:8765 and open http://localhost:8765, or the Chrome flag "Insecure origins treated as secure".

Several apps on one controller. The controller belongs to the one app that connected it; every other app (a bass synth, a second AXIOM) only shares its blocks and receives the pad presses. Apps with the same ROOM share, in windows of the same browser at once, between devices through OTHER DEVICES (the AXIOM server relay). If two apps both connect, the lower session id keeps the controller. Developers: docs/GRID_HANDOFF_BASS_SYNTH.md describes the protocol and the two small files to copy.

The APC Key 25 mk2 also wants its start-up message (a short introduction message the Akai protocol asks for before other messages): it is sent when you connect and can be switched off with the start-up message box.

Control index

Every operable control in the app, generated from the running app by tools/docs/gen_control_index.py (1219 controls). The same text appears as the tooltip when you hover over the control. Regenerate after changing controls.

Top bar

Pads

Pad editor: sample engine

Pad editor: subtractive synth

Pad editor: additive synth