Norilsk

A firmware for the M-VAVE FM-1 for inhospitable soundscapes.

Norilsk is not made for musical niceties. There are no pretty chords here, no polite arpeggios, no presets that flatter. It is made for ambient hellscapes and barren, grim atmospheres: drones that never resolve, textures that corrode as they hold, noise that does not apologise. Sound for places nobody should have to live in.

It is named after Norilsk, the nickel-smelting city above the Arctic Circle: built by prisoners of the Gulag, closed to outsiders, sunk in polar night for weeks each winter, its air thick with sulphur dioxide, its rivers turned red by the works upstream. Every sound here is drawn at random, wired at random into effects drawn at random, and torn apart at will: as fit for noise experiments as for slow, dark ambient.

Website, browser installer and session backup: https://nzimas.github.io/norilsk/

State: build 48. Each build is described in CHANGELOG.md. Norilsk was called Molecular until build 17.

Manual

First steps

1. Power on. Generator 1 is chosen; each generator already has a sound and a lane of effects.
2. Play white keys. Press FX, SEL or ENV to hear the other generators.
3. Press HOME until a generator sounds right to you. SHIFT + HOME keeps its family and tries again.
4. Hold a key and press SHIFT to latch it. Latch notes on two or three generators to build a texture.
5. Turn KNOB 2 for more or less effect, KNOB 1 to disintegrate, KNOB 3 and KNOB 4 for delay and reverb.
6. Press SAVE, hold a white key 0.8 s: the whole machine is stored in that snapshot. Make a few, set a morph time with KNOB 1 and move between them.
7. Hold SAVE (outside the SNAPSHOTS page) to keep everything in the FM-1's flash as a session.

Cheat sheet

SHIFT is the rightmost black key. Black keys are contextual: a key with a job in the current view glows dimly (lit when on); a key with none does nothing and stays dark. "Hold" means 0.8 s unless stated otherwise.

Slots

To	Do this
Choose generator 1, 2 or 3 (keys play it)	Press FX, SEL or ENV
Choose effect slot (lane) 1, 2 or 3	Press LFO, EDIT or GLO
Mute or unmute a slot	Hold its button
Mute fade in / fade out of a generator (OFF to 60 s)	SHIFT + its button, let go: its page. KNOB 1 MUTE FADE IN, KNOB 2 MUTE FADE OUT. Its button to leave
Level / pan of chosen generator (pan moves its lane too)	Turn SELECT / ALGORITHM
Link two generators (first modulates second)	Hold SHIFT, hold first generator's button, then hold second's. Repeat to unlink

Playing

To	Do this
Play	White keys: chosen generator, in current scale. Keys playing the scale's root glow dimly
Play from a MIDI keyboard or computer	USB or the TRS MIDI IN jack: channels 1, 2, 3 play generators 1, 2, 3; channel 16 the chosen one (GLOBAL SETUP changes them)
Change octave (−3 to +3)	OCT− / OCT+
Latch a note	Hold white key, press SHIFT (key stays lit)
Release a latched note	Hold SHIFT, press lit key
Set root and scale	ARP opens SCALE page: SELECT root, ALGORITHM scale (23). ARP again to leave
Random root and scale	SHIFT + ARP (let go at once; held, it opens PRESETS)
DISINTEGRATOR of generator being played (0 to 100)	KNOB 1
Master DRIVE (0 off to 100)	SHIFT + KNOB 1
FX MIX of chosen lane, dry to wet	KNOB 2
Delay send / reverb send of generator being played	KNOB 3 / KNOB 4
Output level	MASTER

Drawing new material

To	Do this
New sound for chosen generator (with its lane's effects)	HOME
New effect chain for chosen lane	Choose the effect slot, press HOME
New, but same family (or same recipe)	SHIFT + HOME
Pick a family (generator) or recipe (effect slot)	Hold SHIFT, turn PRESETS: alphabetical list, four per page. Then SHIFT + HOME draws a new one of it
Everything new, all six slots	Hold HOME
New cables only	1st black key (REWIRE)
New values only (effects), or new sound of same family (generator)	SHIFT + 1st black key (RAND PARAMS)
Bias draws towards harsh, torn material	2nd black key: ABRASIVE path on/off
Bias draws towards dark ambient and drones	3rd black key: DARK path on/off
Draw industrial percussion: struck metal, machines	4th black key: MACHINE path on/off

Pages

To	Do this
Delay settings (TIME, FEEDBACK, DAMP, MIX)	SEQ, then KNOB 1 to 4
Reverb settings (SIZE, DECAY, DAMP, MIX)	SEQ twice, then KNOB 1 to 4
Modulation of chosen slot	SEQ three times. PRESETS picks LFO 1, LFO 2 or route A to H; KNOB 1 to 4 set its values
Back to playing	SEQ a fourth time
A generator's page (MUTE FADE IN, MUTE FADE OUT)	SHIFT + its button, then KNOB 1 / KNOB 2. Its button to leave
Random modulation for chosen slot	SHIFT + SEQ
GLOBAL SETUP (MIDI, USB audio)	Hold SHIFT, hold SAVE 0.8 s. PRESETS moves, SAVE chooses, SHIFT + SAVE goes back (from the top: out)

Looper (generator being played)

To	Do this
Record a loop	REC to arm (first note starts it), REC again to end (plays at once)
Overdub	REC while loops play
Clear loops	Hold REC 1 s
VARY on/off	SHIFT + REC
Stop or restart loops	PLAY
Stop or start all generators' loops	SHIFT + PLAY
Take loops out or bring them back	Hold PLAY, press white keys
REVERSE, PENDULUM, RANDOM, HALF SPEED, DOUBLE SPEED	Hold PLAY, press 4th to 8th black key (again: off)
Move loops one scale step down / up	SHIFT + OCT− / OCT+ (hold a generator's button too for its loops only)

Snapshots

To	Do this
Open SNAPSHOTS page	SAVE (again, or a slot button, to leave)
Recall snapshot	Press and release its white key
Store current state	Hold its white key 0.8 s, or move frame with PRESETS and hold SAVE
Empty snapshot	Hold SHIFT, hold its white key
Morph time (0 to 30 s)	KNOB 1 on SNAPSHOTS page

Sessions

To	Do this
Save while playing	Hold SAVE (saves into loaded session; with none loaded, offers first empty slot)
Clear: a new session in place of the one loaded	10th black key (beside SHIFT): NEW SESSION? PRESETS to YES, SAVE. The saved one stays in the flash until you save over it
Open SESSIONS list	SHIFT + SAVE (let go at once; held, it opens GLOBAL SETUP)
Pick a session	PRESETS
Open its page (BACK, LOAD or NEW, SAVE, COPY, DELETE)	SAVE
Pick and run a row	PRESETS, then SAVE
Go back a level	SHIFT + SAVE

Presets

To	Do this
Open PRESETS for the generator being played	Hold SHIFT, hold ARP 0.8 s
Pick a slot (64)	PRESETS
Load it into the generator	ARP or SAVE (back to playing)
Save the generator into it	Hold ARP or SAVE. Over a full slot: OVERWRITE? PRESETS to YES, ARP
Leave	SHIFT + ARP, SHIFT + SAVE or a slot button

Start-up

To	Do this
Rescue mode (install again)	Hold OCT− while powering on
Chip's own updater	Hold OCT− and OCT+ 5 s

How it is put together

Norilsk has three generators, three effect slots, a master delay and a plate reverb. I think of the generators as furnaces: each burns a sound. Effect slots are the pipes the sound runs through; delay and reverb are the air the fumes end up in. In practice:

• Each generator plays through its own lane of effects: generator 1 through lane 1, 2 through 2, 3 through 3. A small dry part of each generator also goes straight to the master.
• Each lane is a chain of two or three effects, drawn from a recipe. An effect before the last can also send to the master on its own.
• White keys play the generator chosen last, in the current scale. Four voices are shared by the three generators.
• Each generator has level, pan, mute, delay and reverb sends, a looper and a DISINTEGRATOR. Each lane has level and mute. A generator's pan also pans its lane and every effect in it: panning is set on the generator only.
• One generator can modulate another (ring, amplitude or filter), but only if you link them by hand: hold SHIFT, hold one generator's button, then the other's.

CPU core 1 renders the voices. Core 2 runs the effects, delay and reverb, one block (0.73 ms) behind.

Every sound swells in and keeps moving. However, nothing sounds on once no note is held, latched or looped: released voices fade out within three seconds, and effect slots close two seconds after the last voice. Delay and reverb are the exception: their tails always ring out in full, whatever you let go or mute.

What is random and what isn't

Almost nothing is set by hand at the start. It is drawn at random; your job is to choose, keep, throw again and play. Randomness works at every scale:

1. Sound. FURNACE, the engine, draws a sound from family, seed, path and engine generation. The same four values always give exactly the same sound, so a session only needs to store the seed.
2. Note while it sounds. An invisible hand (after Anima) keeps moving each voice's four macros. Russolo's grit drops bits, crosses the sound with itself and makes it stutter. Grains are read from places that wander. In other words, the same key held twice never sounds the same twice.
3. Generator (HOME on a generator): scene, family (chosen by how harsh it may be), which effects it is cabled into, and how much of it is heard dry.
4. Effect slot (HOME on an effect slot): one of 38 recipes. Each place in the recipe gets one of its allowed effects that fits the slot's memory; every value is drawn around its default, and the outs are drawn too. In a twin recipe the second effect is the first again, its values drawn from the first's and kept apart. HOME on a generator also draws its lane's chain.
5. Paths. ABRASIVE and DARK bias every draw above: scenes, families, recipes and effect values. MACHINE draws only the struck families and the recipes that suit a strike.
6. Partial draws. REWIRE draws only cables. RAND PARAMS draws only an effect slot's values, or a new sound of the same family for a generator. SHIFT + HOME keeps family or recipe. Holding HOME draws all six slots.
7. Modulation. SHIFT + SEQ draws a slot's two LFOs and two to six of its eight routes. STEPS and DRIFT shapes and the RANDOM source keep drawing new values as they play.
8. Playing. DISINTEGRATOR gates, stutters, crushes and pans each generator in pulses of random length. Looper's VARY changes every note it plays; RANDOM jumps between loops.
9. What isn't random. A snapshot stores the whole machine and recalls it exactly, or morphs into it. Sessions keep everything in flash.

Screen

Designed for low vision: few words, very large type, high contrast.

Main view is drawn as a place. Smog drifts slowly across the top, with audio load on the left and battery on the right. Below ground, the three effect slots are rusty pipes, one above the other. Each effect is a section between bolted flanges, its name on a dark plate: FLT filter, FLD fold, MU mulaw, SHF shift, MDL modal, STR string, VOX vowel, TAP tape, RVS reverse, SPR spring, GLT glitch, CLD cloud, SCR scream, RNG ring, STV starve, CHB cheb, BNK bank, SMR smear, DIF diffuse, SLW slew, XOR xor, DST dust, WST waveset, XMD xmod, CHS chaos.

Under each name, a band shows the colours of the generators feeding it. Plates fed by the chosen generator are filled with its colour. A section glows hotter while sound passes through it; a muted pipe is cold grey.

At the bottom, the generators are brick furnaces, fire in their mouths in their colours (red, blue, green): brighter while they sound, dark when muted. Chosen slot has a white frame. Cables are not drawn. KNOB 1 shows its value on a full-screen dial.

On the settings pages (DELAY, REVERB, MOD, a generator's page) each setting's name is amber and its value white. The setting just turned is black on white, its name dark amber.

Messages (LANE 2 REWIRED, GEN 1 WIRE, OVERLOAD) cover the top of the screen for a moment. One too wide for a line takes two; a line still too wide drops one size. No word runs off the screen.

Generators

Each generator runs an instance of FURNACE, the engine, playing one sound drawn from forty-four families. Four voices are shared by the three generators, and each voice is a complete instance of the engine. Because of this, one sound on two keys never sounds quite the same. Details: FURNACE engine below.

Mute fades

SHIFT + a generator's button, let go, opens its page: GEN 1, GEN 2 or GEN 3 at the top, two settings below.

• MUTE FADE IN (KNOB 1): how long the generator takes to come back when its button is held to unmute it.
• MUTE FADE OUT (KNOB 2): how long it takes to fade away when its button is held to mute it.

Each OFF (at once, as before) to 60 s: half-second steps to 10 s, whole seconds above. Both OFF at power-on and in a new session. The fade falls evenly in loudness; the generator's sends to its lane and to the master delay and reverb fade with it. Muted or unmuted again halfway, it turns back from where it is. Kept in snapshots and sessions. A snapshot recalled at once, or a session loaded, sets the mutes at once; a morph glides them over its own time.

The generator's button, or SHIFT + it again, leaves the page. Holding SHIFT with one generator's button and then pressing another still links them (no page).

DISINTEGRATOR

KNOB 1 while playing sets the DISINTEGRATOR of the generator the keys play, 0 to 100. It is an unstable gate after the sound is made and before its cables, so effects hear it too.

It cuts the sound into pulses of uneven length. Each pulse lets the sound through, gates it down (to silence from 60 upwards), repeats a 10 to 90 ms slice of what was just played, or crushes it (bits and sample rate). A pulse may also throw the dry part across the stereo image.

Higher values give shorter, more irregular pulses, more of them acting, deeper and wider. Every edge is smoothed over about 1.5 ms, so no clicks. At 0 nothing is touched. Each generator keeps its own value in snapshots and sessions.

Ideas from Destroy FX's Skidder and from buffer repeaters; none of their code.

FURNACE engine

FURNACE started as Tonitor's FM engine and was rebuilt around one goal: sound that is never struck, never still and never exactly the same twice. Struck sound came later, on a path of its own (MACHINE, generation 7).

It works on one voice, one note and one block of 32 samples (0.73 ms at 44.1 kHz) at a time. Everything is integer maths, because the chip has no floating point; per-sample code runs from RAM. Code: firmware/src/mol.c (voice and draw), fm6_core.c (operators), wt.c (waves), found_clips.h (found sounds).

Voice signal path

Every block goes through these stages, in this order:

1. Hand (generation 3). An invisible hand rests on each voice (after Anima: Tonitor's version, from Vascular). One finger drags figures across a surface: orbits, figures of eight, scribbles, slow glides, now and then a flick. It presses in slow swells and sometimes lifts to land elsewhere; a second "ghost" finger comes and goes. Finger position, pressure, speed, angle, distance and age are read once a block. Two to four of them, chosen when the sound is drawn, are mapped to brightness, cloud, level, grit, glitches and cloud darkness. Never to pitch.
2. Operators. Six-operator FM: msfa (Dexed's core) in Felucca's integer port, as Tonitor shaped it. DX7's 32 algorithms, four-rate / four-level envelopes, keyboard scaling, ratio or fixed frequencies, feedback, LFO. Each operator reads a sine or one of 28 band-limited single cycles (four primitives, Bigorna's sixteen harmonic sets, eight made for bells). A wave can morph towards the next in its bank, and its phase can be bent as on the Casio CZ: a sine opens like a filter, a square's width follows its envelope. Each wave has eight levels of detail; one is picked every block from the operator's frequency, so the wave itself never aliases. Macros act here: BRIGHTNESS on modulator index, DETUNE (or INHARMONIC) on ratios, MOTION on LFO and tremolo. Finally a 7 Hz high-pass removes the DC that FM produces, and the sound's measured gain is applied.
3. Exciter and body (generation 4). Operator output, noise or a bow drives a body tuned to the note. TUBE is a waveguide: a delay line one period long, damped and low-passed inside its loop, with an allpass adding a wire's stiffness (partials pulled apart). Open, or closed at one end for odd partials only. MODAL is six resonators on the ratios of a bar, plate, bell, closed pipe or hull, slightly detuned. The bow is Smith's bowed-string model: friction that grips while string and bow move together and slips when they don't. A body rings 2.5 s at most and never bends pitch.
4. Grit (generation 3). Russolo's, after Robert Heel's Noisferatu. Three parts: a small DAC (bits dropped, each sample held several times); XOR of the sample with a triangle at a ratio of the note (logic oscillators); and stutters, looping the last 5 to 120 ms 3 to 12 times before carrying on. Mixed with the clean sound; the hand moves both mix and stutter chance.
5. Grains. Everything above is written continuously into the voice's own buffer: 12288 samples at 22.05 kHz, 8-bit mu-law, about 0.56 s. Up to four grains at once read it back, in one of two ways. CLOUD: grains of 2 to 400 ms at their own rate (1 to 400 per second), starting at a drifting point behind the write head; jittered in time and level, pitched by the sound's intervals, sometimes reversed, darkened by a low-pass, fed back into the buffer so the cloud smears on itself. When the sound asks for it, the cloud is : the buffer stops recording a moment after note-on and the cloud keeps turning over what it holds. (after Curtis Roads): grains locked to the note's period, half a grain to four per period. One grain per period reads the sound back as a formant; a burst mask drops some grains, adding a sub-harmonic. From generation 5, a share of grains reads a found sound instead (see below). GRAIN macro changes the cloud's share and rate, and gives a sound without a cloud the cloud drawn with it.

A voice ends when its note is released and it has been silent for a quarter of a second, or when operators, body and cloud have nothing left. Separately, generators fade a released voice out within three seconds.

Found sounds (generation 5)

Sixteen 0.6 s clips in flash, 8-bit like the grain buffers, each looping without a seam:

• Ice and sea, from NOAA hydrophones: iceberg calving, its tremor, icequake, grounding, ship above the Challenger Deep.
• Aurora radio emissions, from NASA's Polar spacecraft: auroral hiss (twice), kilometric radiation, chorus, "saucers".
• Plant, rendered here: transformer, air duct, furnace, rain on tin, engine room, wind in wires.

A grain can start anywhere in its clip. Playback rate follows the keys only by a drawn share, so clips are barely transposed. DEPTHS, AURORA and PLANT take 70 to 100 % of their grains from a clip. Older sounds with a cloud get a clip one time in three, for 30 to 60 % of their grains. Sources and credits: found/CREDITS.md.

How sounds are drawn

A sound is drawn from four values: family, seed, path and generation. Same values, same sound, bit for bit. This is why sessions store seeds, not sounds. Order of the draw:

1. Family. From the generator's scene and a harshness budget (HOME), or kept (SHIFT + HOME). Scene also sets the path: FIELD ambient, MATERIAL open, FEEDBACK and EROSION experimental.
2. Body. One of eight FM bodies. Newer families each borrow one and build on it.
3. Family features. Cloud, shattered grains, pulsars, freeze, grit and logic, exciter and body, or found sound.
4. Path. AMBIENT: slower and darker (longer attacks and releases, modulators down, longer cloud, an octave down one time in three). EXPERIMENTAL: harsher (modulators and feedback up, mutated more often than not). Open path: one sound in three mutated. A mutation fixes a partial to a frequency, turns an envelope upside down, pushes feedback, moves an octave, replaces a sine with another wave, or bends one.
5. Care. Modulators on high ratios turned down, index scaled down the keyboard, rate scaling on carriers.
6. Generation 2 rule. Every sound swells in, holds and keeps moving: slow LFO (0.1 to 1 Hz) on modulator levels, no pitch envelope, cloud fading in.
7. Later generations. Hand on most sounds (85 %). Grit on some older families on the experimental path. Body for one older sound in five; found sound for one older cloud in three.
8. Sanitiser. Every value forced into range.
9. Measurement. Sound rendered for 2.5 s at middle C, outside the audio path; its loudest 46 ms brought to a fixed level. Boost limited to +15.6 dB, so a slow swell stays a swell.

Engine generations

A sound keeps the generation it was drawn under, and a generation never changes what it draws. Tests check this with a hash of hundreds of sounds per generation. In practice, a session from an older build sounds exactly as it did. New sounds are always drawn on the newest generation.

Generation	Added
0	FM with waves in the operators, grains, twelve families
1	No pitch bends in bodies (no zaps, no bleeps), tonal ones roughened; no freeze before the body has sounded
2	Textures and drones only: IMPACT and PULSE no longer drawn; every sound swells in, holds and keeps moving
3	Hand, grit, eight families
4	Exciter and body, five families
5	Found sounds, three families
6	Eight families; one older sound in four gets other waves (harmonic sets, bells, bent)
7	Struck: eight families of industrial percussion, drawn only on the MACHINE path. Older families as in 6
8	ANVIL, STAMP, RIVET and SHEET strike again while held, on an unstable clock. The rest as in 7

Families

Family	Gen.	What it is
METAL	0	Risset's bells and gongs: many carriers on inharmonic ratios, high partials dying first
DRONE	0	Slow pairs, near-harmonic, detuned to beat, wandering index
BRUIT	0	Noise from feedback and high ratios, scattered by a sample-and-hold LFO
IMPACT	0	Struck body, modulators dying first (not drawn from generation 2)
PULSE	0	Sound pulsed by its own LFO (not drawn from generation 2)
GLASS	0	Carriers on bell waves, morphed, barely modulated
FORMANT	0	CZ approach: carriers bent by their envelopes under a modulator at the fundamental
REED	0	Saw or square whose width follows its envelope, under a feedback operator
CLOUD	0	Body under a slow cloud: long grains, pitched, dark, smeared
SHATTER	0	Body broken into short grains: fast, jittered, reversed, scattered
PULSAR	0	Sustained body read back one grain per period: formants, sub-harmonics
FREEZE	0	Body frozen into a cloud a moment after it starts
FURNACE	3	Low and roaring, crushed, dark cloud over it
HUM	3	Machine room: carriers fixed near 50 and 100 Hz, beating, XOR'd
STATIC	3	Feedback noise, crushed hard, stuttering, shattered
HOWL	3	Formants an octave down under long, dark grains
SCRAPE	3	Scraping metal: high inharmonic partials, bent grains, held samples
DATA	3	Glass through bitwise logic, crushed, stuttering, bent pulsars
ASH	3	Dark drone under sparse, dusty crackle
TUNNEL	3	Huge dark cloud, fed back, sometimes frozen
WIRE	4	Stiff wire bowed by friction, operators as the bow arm
STEAM

Macros

Four macros, each -64 to 64. At 0 the sound is exactly as drawn. There is no page to set them by hand: the hand moves them, and so do modulation routes (MOD page) aimed at them. Response follows the square root of the knob's travel, so the first part of the turn does the most.

• BRIGHTNESS: modulator index about 27 dB either way, higher carriers tilted up, feedback with it.
• DETUNE: carriers pulled apart (up to 40 cents), modulators moved off their carriers. On metallic and noisy bodies it becomes INHARMONIC: every operator except the lowest carrier moved off its ratio.
• GRAIN: cloud wetter and faster, or drier and slower. On a sound without a cloud, fades in the cloud drawn with it.
• MOTION: LFO depths, a tremolo (1.5 to 6 Hz), grain drift.

Hand and modulation routes can move the macros at the same time.

Effect slots

Twenty-five effects, two or three per slot. SMEAR to DUST came in build 32, WAVESET, XMOD and CHAOS in build 45; their names are provisional. Delay and plate reverb belong to the master only (since build 30). A session saved with them in a slot loads them as TAPE and SPRING.

Effect	What it is
FILTER	Driven state-variable filter: low-pass, band-pass, high-pass or notch. Resonant to the edge of screaming, never piercing
FOLD	Wavefolder, with a second fold and a tone control
MULAW	Rate and bit reduction, filter open enough to alias, drive into it
SHIFT	Frequency shifter: every partial moved by the same 40 to 900 Hz, tearing the harmony apart
MODAL	Three tuned resonators, spread inharmonically, ringing up to Q 325
STRING	Three Karplus-Strong strings on the scale's root, ringing up to 8 s
VOWEL	Three formants morphing through vowels, driven
TAPE	Echo through a worn head: dropouts, saturation, age, hiss under the sound
REVERSE	Windows of the sound played backwards, fed back
SPRING	Spring tank, with its chirps
GLITCH	Russolo's bent buffers: jumps and stutters through the last 0.74 s, never at another pitch
CLOUD	Granular cloud that can freeze what it holds
SCREAM	Shaped feedback howl
RING	Diode ring modulator modulating itself
STARVE	Starved, gated fuzz (after the Fuzz Factory)
CHEB	Harmonic re-voicer using Chebyshev polynomials (after Airwindows' Pafnuty)
BANK	Inharmonic resonator bank: bar, plate, bell, membrane (after Mutable Instruments' Rings)
SMEAR	Sound through twenty random taps, each + or −, over 12 to 46 ms: grainy haze rather than a room (velvet-noise decorrelator)
DIFFUSE	Four allpasses in series (lengths from Mutable Instruments' Clouds): blurred edges, no tail of its own
SLEW	Limits how far the sound can move in one sample: highs turned into dark, grinding ramps (after Airwindows' Slew)
XOR	Sound combined bit by bit (XOR, AND, OR) with itself a moment earlier: broken and digital, but following its shape
DUST	Hiss and crackle where the sound moves, none where it is still (after Airwindows' TapeDust)
WAVESET	Sound cut at its zero crossings into its own small cycles, replayed a group at a time: repeated, reversed, shuffled or left out (after Trevor Wishart). Grain, never rhythm

Last three follow what goes in more than their own values: same values on a drone, a cloud and a hiss give three different things.

Thirty-eight recipes decide which effects may stand at each place: SPACE, ECHO, METAL, STRINGS, EROSION, GHOST, SPECTRAL, RESONANT, FOLDS, TELEPHONE, HELL, FACTORY, GLITCH, BROADCAST, ABYSS, RUST, FREEZER, FEEDBACK, FOUNDRY, GONG, SPECTRE, SPUTTER, SMOG, STATIC; with the new effects, SHATTER, MOSAIC, CROSSFIRE, ATTRACTOR, TURBINE.

Twin recipes put one effect twice in a row: MIRRORS (SHIFT), FOLDOVER (FOLD), CLANGOUR (RING), CRUSH (MULAW), OVERTONE (CHEB), SHATTER (WAVESET), CROSSFIRE (XMOD). Second one's values are drawn from the first's and kept apart: shifter going the other way, ring and crusher at another rate, another shape, mode or algorithm. In SWARM (CLOUD), LOOPHOLE (GLITCH), CAVERN (SPRING) and FOG (SMEAR) the second also feeds back into the first. The feedback follows what comes into the lane: no sound in, it dies within about 2 s. Recipe names are provisional.

Every effect falls silent with nothing coming in. None sounds on by itself.

Lanes

Generator 1 plays through lane 1 only, generator 2 through lane 2, generator 3 through lane 3. Each generator is cabled into the head of its lane, with a small dry share. No cables between lanes. A lane has no pan of its own: it and every effect in it follow its generator's pan (centre, left and right at power-on).

HOME on a generator also draws its lane's chain, so the chain is part of the generator's patch (SHIFT + HOME keeps family and recipe). HOME on an effect slot redraws that lane and keeps its generator. REWIRE inside a lane redraws where the generator enters and which effects also send to the master. Holding HOME draws all three generators and their lanes.

From build 28 to 35 a session could also be MESH: any generator cabled into any effect, effects cabled across slots. In practice it mostly produced smear, so from build 36 there are only lanes. A MESH session loads rewired into lanes, snapshots included, nothing redrawn.

Paths

Three black keys bias everything HOME draws, and RAND PARAMS too:

• ABRASIVE (2nd black key): gnarly, textural, torn. Favours experimental scenes; harsh families (BRUIT, SHATTER, FURNACE, STATIC, SCRAPE, DATA, METAL); more cables and cross-modulation; torn and crushed recipes; more drive, breakage and crushing in effects.

• DARK (3rd black key): dark ambient, drones, introspection, along the lines of Lustmord and the Cold Meat Industry catalogue. Favours the FIELD scene; drones, hums, tunnels, ash and freezes, nothing harsh; spacious and ringing recipes (SPACE, GHOST, ABYSS, FREEZER, RESONANT, GONG and others); darker, less driven values, larger spaces. Also 3 dB quieter.

• MACHINE (4th black key): industrial percussion. HOME on a generator draws only the struck families (ANVIL, STAMP, RIVET, SHEET, GEARS, PISTON, RATCHET, FORGE): metal against metal, presses, pistons, gears. No drums. The first four strike at the key, then again while it is held on a very unstable clock: intervals from 40 ms to 2.5 s, clusters, long pauses, each strike at its own level (softer ones darker) -- a percussive texture, nothing to count. The other four are machines: they keep striking on their own while the key is held, each strike a little early or late, the pace wandering, no tempo. Let go, they stop and ring out. (Sounds saved in build 47, generation 7, keep their single strike.) HOME on an effect slot favours rooms, echoes, metal resonances and crushing; not frozen clouds or smoke, which would hold a strike into a drone. The struck families are never drawn on the other paths. SHIFT + HOME on a struck sound keeps its family on any path.

One path at a time. With none on, anything goes (nothing struck). Path is saved with the session and with each snapshot.

Modulation

Every slot, generator or effect slot, has two LFOs and eight routes, A to H.

• LFO shapes: SINE, TRI, SAW UP, SAW DOWN, SQUARE, STEPS, DRIFT. Each LFO runs FREE, restarts on each NOTE, or runs ONCE, and has a fade-in.
• A route goes from a source (LFO 1, LFO 2, VELOCITY, KEY, RANDOM) to a destination, by an amount.
• Generator destinations: four macros, level, pan, sends, LFO rates.
• Effect slot destinations: effect values by place, level, LFO rates (a lane's pan is its generator's). Routes point at a place, not at an effect, so after HOME draws new effects the LFO moves the new effect's value at that place.

SEQ's third page sets them; SHIFT + SEQ draws them at random.

Snapshots and sessions

A snapshot is the whole machine. Every slot's sound, effects, values and cables; levels, pans, mutes, mute fades and sends; DISINTEGRATORs; FX MIX; master delay and reverb; modulation; scale and root; octave; path. It also stores how the machine is being played: latched notes, whether each generator's loops are playing, which loops are taken out, their direction and speed, VARY, and moves along the scale. Loop recordings themselves belong to the session. Sixteen snapshots per session.

SAVE opens the SNAPSHOTS page. Release a white key to recall its snapshot. Hold it 0.8 s to store the current state in it. Hold SHIFT as well to empty it.

KNOB 1 on this page sets morph time, 0 to 30 s. A recalled snapshot moves into place over that time. Levels, pans, sends, values and LFOs glide. Sounds cross-fade on voices of their own; effect chains fade out and in, one after the other. Anything without an in-between value switches halfway. The target snapshot's square and key blink until the morph is done.

SHIFT + SAVE opens the SESSIONS list, as on Bigorna: four per page, PRESETS moves through 64 slots. Saved session white, empty slot grey, loaded one marked on its right. SAVE opens the slot's page:

• BACK
• LOAD, or NEW on an empty slot (clean slate)
• SAVE (asks first before overwriting another session)
• COPY to a slot chosen with PRESETS. First empty slot offered; copying over a session asks first
• DELETE (asks first)

PRESETS moves through the rows, SAVE runs the selected one, SHIFT + SAVE goes back a level. While playing, holding SAVE saves straight into the loaded session. A session holds the machine, its sixteen snapshots, latched notes and every loop, in the FM-1's flash.

Presets

Hold SHIFT and hold ARP 0.8 s: the PRESETS page, for the generator being played (its number in its colour at the top right). 64 slots. A preset is one generator's patch: its sound, its lane (effects, values, outs, return), how it is cabled into the lane, its DISINTEGRATOR and its lane's FX MIX. Level, pan, delay and reverb sends, modulation and mute are not part of it: they belong to the mix.

A preset is named by its sound's family and numbered within that family, in slot order: ANVIL 1, ANVIL 2, DRONE 1. Empty slots are grey.

• PRESETS chooses a slot.
• ARP (or SAVE) loads it into the generator and goes back to playing. A preset saved from one generator loads into any other, in that generator's own lane.
• ARP (or SAVE) held 0.8 s saves the generator into the slot. Over a full slot it asks OVERWRITE?, NO first.
• SHIFT + ARP, SHIFT + SAVE or a slot button leaves.

Presets are kept in the flash apart from the sessions, like the global setup, and backed up with them.

Norilsk only writes to blank flash or to its own retired sessions, never over another firmware's data. Other firmware does not return the favour, however: back up your sessions before installing something else.

Looper

Each generator has Tonitor's looper: up to ten free-running loops, each on its own clock. No tempo, no grid.

Press REC to arm a loop; the first note starts it. Press REC again to end it; it plays at once. Press REC again while loops play to overdub. A note held across the end of a loop is tied over.

Hold PLAY to show loops on the white keys and take them out or bring them back. This also lights the 4th to 8th black keys: REVERSE, PENDULUM, RANDOM, HALF SPEED, DOUBLE SPEED. SHIFT + OCT moves all loops along the scale; SHIFT + REC turns on VARY.

Backing up sessions

The website's backup page saves every session on the FM-1 to a file, with the global setup and the presets, and writes them back, from desktop Chrome, Edge or Opera.

From a terminal: tools/fm1_sessions.py lists sessions, tools/fm1_sessions.py save N saves one, tools/fm1_sessions.py restore FILE writes one back. Page and script only talk to an FM-1 whose USB name is FM-1 Norilsk.

USB audio

Connected to a computer, the FM-1 is also a class-compliant USB audio interface: no driver needed. It sends 16 bits, 48 kHz (or 44.1 kHz), taken before the MASTER knob: recordings don't follow the headphone level. Code from Tonitor and Bigorna.

GLOBAL SETUP, AUDIO > USB chooses what it sends:

• STEREO (default): the master, left and right.
• TRACKS: three channels, one per generator, mono: the generator with its lane of effects, after its level, before its pan, the master delay and reverb, and the drive. For recording each generator apart.

Changing it, the FM-1 leaves USB for a moment and comes back as the new device.

Global setup and MIDI

Settings of the machine, not of a session. Hold SHIFT, hold SAVE 0.8 s. PRESETS moves through the list, SAVE chooses or sets, SHIFT + SAVE goes back a level (from the top: out). A slot's button also leaves. Changes are written to the flash on leaving. Sessions and snapshots never change them; the backup page saves them with the sessions.

Setting	Default
MIDI > IN CHAN: GEN 1, 2, 3; AUTO (the generator being played)	1, 2, 3; 16
MIDI > OUT CHAN: GEN 1, 2, 3	1, 2, 3
MIDI > RECEIVE: NOTES, CC	ON, ON
MIDI > SEND: NOTES, CC	OFF, OFF
MIDI > PORTS: USB IN, TRS IN (the 3.5 mm MIDI IN jack)	ON, ON
AUDIO > USB	STEREO

MIDI in plays each generator on its channel, from USB or the TRS jack. CCs set the generator on that channel:

CC	Sets
7	Level
10	Pan
16	DISINTEGRATOR
17	FX MIX of its lane
91	Reverb send
92	Delay send

With SEND on, each generator's notes (keys, loops, MIDI) and those CCs go out on its OUT channel. A note sent on is always sent off on the same channel, even if the setting changes while it sounds. No clock, no transport.

Building from source

./setup.sh once: a Python environment, JieLi's toolchain and three files of the AC79 SDK (Tonitor's procedure). On macOS, Docker Desktop must be running to build. Then:

./build.sh

It must print package ... build N with no FAIL. ./install.sh builds and installs over USB; ./install.sh --no-build installs build/norilsk.fwsc as it is; ./install.sh FILE.fwsc installs another package; ./install.sh --info says what the connected FM-1 runs.

Running tests

tests/run_tests.sh

Needs clang and python3 with Pillow. It checks the firmware unit for anything the chip's runtime lacks (no float, no 64-bit division), renders thousands of sounds (none silent, none clipping, none running away), plays the panel through the real firmware code, checks every effect falls silent, every recipe fits its slot's memory, snapshots and morphs land exactly, every message fits the screen, sessions survive power cuts and never touch another firmware's flash, and that the engine's generations still draw what they drew. Renders land in build/sounds (WAV), the screens in build/screens (PNG). The website: tools/make_logo.py, tools/make_demos.sh, then tools/make_site.py (into docs/, served by GitHub Pages).

Layout

Path	What
firmware/src/norilsk.c	the single compilation unit: the sources in order
firmware/hal/, crt0.S, app.ld, loader/	the board layer, boot, memory map and update loader (Tonitor's, from Felucca and SLOOP)
firmware/src/main.c, usb.c, ota.c, recovery.c, lcd.c, gfx.c	boot and interrupts, USB, the installer's handshake, the rescue mode, the screen
firmware/src/setup.c, midi.c, midi_uart.c	GLOBAL SETUP, MIDI in and out, the TRS MIDI IN jack
firmware/src/mol.c, fm6_core.c, wt.c	FURNACE: the voice, the grains, the hand, the grit, the families; the FM core; the waves
firmware/src/gens.c	the three generators: the draw, the voices, the two cores, the DISINTEGRATOR, the mix
firmware/src/rack.c, reverb.c	the effect slots: the twenty-five effects, the recipes, the paths, the memory, the cables
firmware/src/mod.c, loop.c, master.c	the modulation; the loopers; the master delay and reverb
firmware/src/sessions.c, backup.c	sessions, snapshots and the morph; the sessions over USB
firmware/src/ui.c	the panel and the screen
tools/	the build, the installer, the sessions tool, the tables, fonts, logo, demos and website
tests/host/host.c	the host harness: every test named above, render, one, replay
docs/	the website (GitHub Pages); docs/ENGINE.md the engine's first design (0.01)
site/	the website's pages, before tools/make_site.py frames them

Licensing

The firmware is GPL-3.0-only (LICENSE); fm6_core.c is msfa under Apache-2.0 (LICENSES/); the website and logo are MIT. See LICENSING.md.

Disclaimer

Norilsk is unofficial. It is not made, endorsed or supported by M-VAVE. Installing it replaces the FM-1's firmware and may void any warranty that applies to your device; an interrupted update can leave the FM-1 unable to start until it is recovered. The software comes with no warranty of any kind; you install it entirely at your own risk. Norilsk is named after the city; it has nothing to do with the company that runs its smelters.