AEther: user manual

AEther is firmware for the M-VAVE FM-1 that turns any sound into a dense, endless cloud. It works like PaulStretch: it takes a long stretch of sound, keeps its colour (the spectrum) and replaces the phases with random ones. The sound loses its attacks and rhythm, and only the colour remains. The keys move that colour to the note's pitch, so you play chords with it.

All screenshots come from the browser emulator, which runs the same code as the device.

Installing

1. Open the web installer in Chrome or Edge, connect the FM-1 by USB (directly to the computer) and press Install. Do not unplug the cable while it writes.
2. When it is done, restart the FM-1: switch it off and on again. The FM-1 starts AEther by itself after the install, but without a full restart the sound can drop out; after one it plays cleanly.

To go back to M-VAVE's firmware, use the installer's "Back to the stock firmware", or M-VAVE's own updater, M-UPGRADE.

The panel

ARP is not used yet, so it stays dark.

Getting around

The pages are grouped under five buttons. Each button has its own pages:

There are three rules:

1. Another group's button brings back the page you were last on in that group. If you were editing LFO 2, went to AMP and pressed LFO, you are back on LFO 2.
2. The same button again goes to the group's next page (after the last one, back to the first). The dots next to the page name show how many pages the group has and which one you are on.
3. HOME always goes back to the main page (SOURCE). Pressed on the main page, it silences all notes.

SEL steps through every page in turn, group by group.

The button map. Hold HOME and the screen shows what each button does right now. The outlined button is the group you are in. Let go of HOME to return.

Button lights. The button of the group you are in is lit brightly, as are PLAY while HOLD is on, REC while FREEZE is on, and SAVE while there are unsaved changes. Buttons that do something glow dimly; the unused ARP is dark.

Quick modulation. Hold LFO (or ENV) and turn a knob on any page. The LFO (or MOD ENV) you looked at last starts moving the parameter under that knob, by as much as you turn. Details in the modulation section.

Presets and your changes. When you change something after choosing a preset, an asterisk (*) appears next to its name in the header. The first turn of PRESETS then only warns ("NOT SAVED"); the next one loads another preset. So your changes are not lost to an accidental nudge. SAVE keeps them.

The screen

• Top: the kind of source (white), the sample or generator picked (orange) and the preset (grey), with an asterisk once you have changed something. On the right HOLD and FREEZE when they are on, and LOAD while the overload guard is working. After each knob move its name and value show here for a moment.

• Middle: depends on the page. Usually the spectrum of the last frame, from 40 Hz to 16 kHz, with a line at every octave. With a sample there is a scan bar above the spectrum: the grey mark shows POSITION, the bright one the place playing now. With HARM you see the harmonics, on the LFO and MOD ENV pages their shape, and on the MATRIX page the list of all eight slots.

• Page name with dots on the right: one dot for each page the current source has; the bright one is where you are.

• Four parameters with a value and a bar. A white mark on the bar means the parameter is modulated and shows where it is right now. The knob itself keeps its value.

• Footer: octave, number of sounding voices (up to 8), processor load, and on the right MOVING or STATIC: whether anything moves the sound over time.

Sources (ALGORITHM and SELECT)

The sources come in five kinds. ALGORITHM picks the kind, SELECT the sample or generator within it. A kind remembers what you last picked in it: back in SAMPLE, the same sample plays. With PAD, HARM and VA, SELECT changes nothing: each is one of its kind.

The header shows the kind (white), the sample or generator picked (orange) and the preset (grey), e.g. "SAMPLE CHOIR GLACIER".

The samples: choir, glass, strings, wind, piano, cello, flute, organ, kalimba, brass, tanpura, rain, birds, whisper, gamelan, tape piano.

With samples, C4 plays the original pitch and other keys shift the whole spectrum.

Pages and knobs

Each page is four parameters under KNOB 1–4. The SOURCE page depends on the source. TONE and HARM ENV A–D are there only with HARM.

SOURCE: sample (CHOIR … TAPE, USER)

SOURCE: PAD

SOURCE: LIVE VOX, LIVE AIR, LIVE BOW, LIVE BELL

These are not recordings but small programs that play C4 all the time and feed the engine, the way VA does. The idea comes from the demoscene's 64k intros: keep the recipe, not the data. Each takes a few hundred bytes of code, has no length and no loop, and changes slowly by itself.

They share the same four knobs, which mean slightly different things for each:

MOVE = 0 stops the source's own motion. The matrix has the destinations LIVE TONE, LIVE MOVE, LIVE CHAR and LIVE DENSITY, and with these sources DRIFT moves TONE, CHARACTER and TILT. Cost: a few percent of the processor (an estimate from a measurement on a computer).

SOURCE: VA

SOURCE and TONE: HARM

HARM builds the sound from harmonics; the screen shows their levels as bars H1–H32 (a 48 dB scale).

A second press of EDIT opens TONE, and further presses the harmonic envelopes HARM ENV A–D. TONE is emphasis or a notch around a chosen harmonic, and the response to velocity.

HARM ENV A–D: harmonic envelopes (EDIT, with HARM)

Four envelopes, each controlling chosen harmonics. They run from the start of each note: they rise over ATTACK to full level, fall over DECAY to the SUSTAIN level and stay there. Harmonics no envelope touches play all the time. When several envelopes hit the same harmonic, their effects multiply.

On an envelope's page the harmonics it controls light up white, and its shape shows in the top right corner. Harmonics of other envelopes are dimmed orange.

Examples:

• ENV A = H3, ATTACK 0.2 s, DECAY 0.6 s, SUSTAIN 0 % (left screenshot): the third harmonic flashes at the start of the note and disappears.
• ENV B = HIGH 13+, ATTACK 4 s, SUSTAIN 100 % (right screenshot): the high harmonics come in slowly and the colour opens up.
• TARGET = H1, SUSTAIN 30 %: the fundamental fades after the attack, leaving the "air".

How the whole note fades after you let go is set separately: RELEASE on the AMP page.

AMP (ENV)

The first page under ENV: the whole note's volume envelope, and the output.

Modulation: LFO 1–3, MOD ENV 1–2 and MATRIX

Modulation has two parts. The modulators (three LFOs and two envelopes) only move; on their own they change nothing. The matrix (MATRIX, the last page under LFO) has eight slots, and each connects one source to one parameter with a chosen amount. One LFO can therefore move several parameters at once, each by a different amount and in a different direction. One parameter can also listen to several sources, and their effects add up.

Modulation adds to the knob's setting: the knob sets the centre and the modulation moves around it. AMOUNT ±100 % means a move over the parameter's whole range, and a negative AMOUNT reverses the direction.

#### Quick: hold LFO or ENV and turn a knob

You do not have to open the matrix. On any page, hold LFO and turn the knob of the parameter that should move. The header shows what you made, e.g. "LFO 1 > CUTOFF +19%". Turning right gives a positive amount, left a negative one, and back to 0 % frees the slot. ENV held works the same way, with a MOD ENV. It uses the LFO (or MOD ENV) you looked at last, LFO 1 and MOD ENV 1 at first. Everything lands in the matrix, where you can refine it later.

If a parameter cannot be modulated (e.g. SIZE or MOTION), the header says "NO MODULATION". When all 8 slots are taken, it says "MATRIX FULL".

#### LFO 1, LFO 2, LFO 3 (LFO)

The screen shows the waveform with a dot at the current place, and above it the LFO's destinations from the matrix.

#### MOD ENV 1 and MOD ENV 2 (ENV, after AMP)

The envelope starts again with every new note (from the keys and from MIDI). It is shared by all voices: it moves a parameter of the whole sound, not of a single note. The screen shows its shape with a line at the current level.

#### MATRIX (LFO, after LFO 3)

The list above the knobs shows all eight slots: source, destination, amount and a bar with the current contribution.

Sources (SOURCE):

Destinations (DEST): STRETCH, POSITION, SPREAD, TILT, SUB, SHIMMER, WIDTH, LEVEL, BRIGHT, BAND, INHARM, ODD, SHAPE, CUTOFF, RESO, SLOPE, EVEN/ODD, FOCUS, BOOST, H BAND, plus LFO1 RATE, LFO2 RATE, LFO3 RATE: the speed of another LFO (one LFO can speed up and slow down another). A destination only works when it applies to the current source: CUTOFF moves the VA filter, for example, and FOCUS works with HARM. Then LIVE TONE, LIVE MOVE, LIVE CHAR, LIVE DENSITY (the LIVE sources) and EQ1–EQ3 FREQ, GAIN, WIDTH, the EQ's bands: a slow LFO on EQ2 FREQ with the bell boosted, for example, sweeps a "vowel" through any source.

By default slot 8 is WHEEL → POSITION +100 %: the mod wheel scrubs the sample. Presets may change that.

On the page of a modulated parameter, a white mark on the bar shows its current value:

The engine takes new values once per frame, every 11–93 ms depending on SIZE. A very fast LFO at a large SIZE will therefore be steppy. This aesthetic likes rates below 1 Hz.

A few ideas:

• LFO 1 → POSITION (SINE, a few seconds) with STRETCH INF scrubs the sample back and forth.
• LFO 1 → FOCUS (TRIANGLE, slow) with BOOST +12 dB gives "vowels" wandering over the harmonics (the HARM VOWELS preset).
• LFO 3 → LFO1 RATE: the vowels speed up and slow down.
• DRIFT → POSITION makes the scan wander around the sample unpredictably (the DRIFT FOG preset).
• ENV 1 → SPREAD with a negative AMOUNT: every new note starts clean and then blurs.
• VELOCITY → BOOST and PRESSURE → SHIMMER: harder playing opens the colour, pressing down adds the octave above.
• RANDOM → POSITION: every note starts at a different place in the sample.
• KEY → TILT: higher notes are brighter.

EVOLVE (SEQ): motion over time

These textures only come alive when they change slowly: over a minute, not a second. The EVOLVE page gathers everything that moves the sound over time. Its four knobs act on all the motion at once.

What DRIFT moves depends on the source:

Above the knobs is a list of what moves right now: DRIFT and its parameters, then every route of the matrix with its amount, its LFO's cycle (with SPEED applied) and a bar with what it adds now.

VARIANT is the quickest way to a moving sound: turn KNOB 4 and listen. The same number with the same source always gives the same motion, so a good one is easy to find again. A variant overwrites the LFOs, MOD ENV 1 and the matrix's slots 1–6 (slots 7 and 8 stay); VARIANT = PRESET brings the preset's motion back.

A hint. If you hold a sound in which nothing moves for 12 s (the footer says STATIC), the header suggests once: "STATIC SOUND? SEQ: EVOLVE".

Every factory preset moves: each has DRIFT, slow LFOs (cycles from ten-odd seconds to a minute and a half) and often an envelope that slowly opens the colour. They make a good starting point: look at EVOLVE and MATRIX to see how they are made.

COLOR (FX)

EQ 1, EQ 2, EQ 3 (FX): a parametric EQ

Three EQ bands act last, on the spectrum, together with TILT. An EQ page shows the whole EQ's curve (the white line, ±18 dB) over the spectrum and the bands' points, this page's band highlighted. The EQ is optional: by default its bands are at 0 dB and change nothing (a low shelf at 150 Hz, a bell at 1 kHz, a high shelf at 5 kHz).

Each band's FREQ, GAIN and WIDTH are matrix destinations (EQ1 FREQ … EQ3 WIDTH), so the EQ can move like any other parameter. A few presets (HARM BLOOM, BELL CLOUD, DAWN and others) use EQ 3 as a gentle high shelf to soften the top.

SETUP (GLO)

The FM-1 has two cores, but its stock firmware uses only one. With 2ND CORE on, the second core paints the spectra of half the voices, which gives headroom with many notes and the HARM source. The core can only be started at power-on, so: set ON, press SAVE, switch the FM-1 off and on again.

The screen shows the state: OFF, RUNNING, DID NOT START (the core did not answer), GIVEN UP: ONE CORE (the core was late or misread a job, so one core plays until power-off) and BARRED UNTIL POWER-OFF (after such an error and a reset). In all these cases the sound carries on with one core. SPLIT FRAMES counts the frames shared between the cores. The second core does not run in the emulator.

The overload guard is always on, with or without the second core. When the processor cannot keep up, AEther first turns off SUB and SHIMMER, then reduces the number of voices (down to two). After three quiet seconds it steps back, one step at a time. You see its state on the SETUP page (OVERLOAD GUARD) and in the header (LOAD).

Presets

Choosing a preset changes the source, every knob, the modulators and the matrix. SAVE stores the current state, including knob changes, but there is only one save slot. With unsaved changes (the asterisk next to the name), the first turn of PRESETS only warns, and the next one changes the preset.

To keep more sounds, store them as user presets (up to 16) from the browser editor: they show in the PRESETS list after the factory ones, under their own names.

Playing

• HOLD (PLAY): play a chord, let go, and it stays. The next chord replaces it. Pressing PLAY again turns HOLD off and releases the notes.

• FREEZE (REC): holds the sample's or VA's spectrum at the current moment. Notes, envelopes and AMP carry on, and the scan moves on from where it was once FREEZE is off. With PAD and HARM the spectrum comes from the knobs anyway, so FREEZE changes nothing.

• Latency: a note starts sounding in the next frame, after ~100–140 ms at SIZE 186 ms and ~20 ms at 23 ms. That is part of the character, not a bug.

• Polyphony: 8 voices. A ninth note takes the quietest voice. When the processor cannot keep up, the overload guard reduces the number of voices for a while (see SETUP).

MIDI

Over USB and the TRS jack:

Notes from the FM-1's keys go out over USB.

The editor in the browser

The project's site has an editor (editor/) that talks to the FM-1 over USB (Chrome, Edge or Opera on a computer; the browser asks for MIDI access with SysEx):

1. Connect the FM-1 running AEther with a USB cable, open the editor, pick the FM-1's port and click Connect.
2. Every page (EDIT, ENV, LFO, SEQ, FX, GLO) is visible at once. A change on the page plays on the FM-1 at once, and a knob turned on the FM-1 shows on the page.
3. Pink marks on the sliders show where modulation (LFOs, envelopes, EVOLVE) moves a parameter right now. The chart on top is the spectrum of what plays, with the EQ curve (as set and as modulated). The matrix shows each slot's source value as it is now.
4. Store as user preset: give it a name (up to 12 characters), pick one of 16 places and store. The preset goes into the FM-1's flash and shows in the PRESETS list (after the 31 factory ones). Save settings does what SAVE does on the FM-1.

Debug (at the bottom of the editor): while it is open the FM-1 reports, once a second, how long each audio render takes (the engine, the source, the modulation), which stages of the engine take the time, and a log of the renders that went wrong (over 80 % of their time, a late frame, an xrun), each with what was running. If the sound glitches, open it, play until it happens, press Copy report and send the text with the bug report.

Double-click a slider to get its default back. With no FM-1 connected the editor is a preview and sends nothing.

Your own sample

pip install numpy mido python-rtmidi
python3 tools/aether_load.py my.wav                 # up to 23 s, 22 kHz + high-band rebuild (SBR)
python3 tools/aether_load.py my.wav --rate 11025    # up to 47 s
python3 tools/aether_load.py my.wav --pcm16         # no compression noise, up to 6 s

After loading, the source switches to USER and the sample stays in memory after power-off. Loading does not work in the emulator.

The emulator in the browser

The same firmware runs in the browser: build it with ./build.sh --web or download the aether-emulator artifact from CI. Click Switch on. Turn knobs by dragging up/down, with the wheel or the arrow keys. To hold a chord with the mouse, Shift-click the keys (the key stays down).