What Macchinetta.AM is
Macchinetta.AM is a groovebox that runs entirely inside a browser tab. There is nothing to install, no account to create and no server involved: the synthesis, the sequencing and the mixing all happen on your own machine, in real time, through the Web Audio API.
It is built around two acid-style synth voices, a four-part drum machine, two samplers, a metallic percussion synth, two granular engines, a drone generator, an arpeggiator, a deterministic glitch processor and a drag-and-drop song arranger. The naming follows Luigi Russolo's futurist taxonomy of noise instruments rather than the usual 303 and 808 vocabulary, which is also a fair description of what the machine is for: it leans towards industrial, noise and rhythmic experimentation more than towards clean dance production.
It is developed and maintained by Retrofuturista, and it is updated continuously: modules get added, reworked and occasionally replaced as the instrument evolves. The version number in the title tells you which build you are looking at.
How to start
Press PLAY in the transport bar, then draw steps in the Pulsator Sequencer grid at the top. Every module has its own grid of eight patterns; the numbered buttons switch between them, and COPY, PASTE and CLEAR work on the pattern you are currently editing. The time signature button cycles between 4/4, 3/4 and 5/4.
Each panel has a small red R in its top left corner that resets that module to its defaults, and a vertical fader on its left edge for its own level. The Combinator is the mixer: one channel per module, with volume and pan.
The modules
Pulsator
The drum machine: kick, snare, hat and clap, with three kits ranging from 808-style to lo-fi to industrial. Each voice has its own distortion, delay, reverb and bit crusher.
Gravis 1 and Gravis 2
Two monophonic subtractive voices with resonant filters, envelope modulation and accent, in the tradition of the acid bass line. Each has its own piano roll, presets and effects, plus a LEGATO switch that makes consecutive notes glide into each other instead of retriggering.
Cubion
A single voice that can be rebuilt as FM, dual-oscillator, subtractive, AM or membrane synthesis. The HOLD button sustains the last note of the pattern, which turns it into a drone that changes pitch when the sequence tells it to.
Ferrum
Metallic percussion: inharmonic frequency modulation with a resonant body, for cymbals, gongs and electric zaps. Three presets cover the extremes, and the sequencer plays it chromatically.
Crepitatore
Granular synthesis on resonant bodies. Each note fires a cloud of grains, and every grain is a very short burst of noise driven into a tuned comb resonator, which is how a struck plate actually behaves. GRAIN sets grain length from 1.5 to 120 milliseconds: below five you get dry crackle, above fifty the cloud fuses into continuous texture. CHAOS scatters the timing and pitch of every grain until a single note disintegrates into a swarm.
Stropicciatore
A granulator that chews on recorded material rather than on synthesis. It works on three sources: five internal materials built from harmonic series, an audio file you load yourself, or a four-second capture of Macchinetta's own output, which lets the machine granulate itself.
POSITION picks the point in the material, SPRAY scatters the grains around it, SIZE sets grain length, OVERLAP their density and JITTER the probability that a grain jumps to a consonant interval. SPEED is bidirectional with FREEZE at the centre: the reading point can stand still, crawl forward or run backwards, independently of pitch.
Rombatore
The drone generator, in five characters: drifting FM, ring modulation, filtered noise, a detuned oscillator stack and a crunchy subtractive voice. Its output passes through soft saturation and a diffuser made of three short modulated delay lines spread across the stereo field, which is what gives it warmth and width instead of the flatness of a single oscillator. PITCH sweeps two octaves either way and glides rather than jumping, so it can be played as a modulation.
Arpeggiator
Eight patterns, from straight up and down to alternating and random walk, over eight note sets ranging from major seventh to whole tone, fifths and diminished. Five synth engines and a frequency shifter.
Replicator and Replicator 2
Two samplers for your own audio, up to twelve seconds each, playable from an on-screen keyboard or from their piano rolls. Unlike the other modules these are polyphonic, so a column of notes sounds as a chord.
Scoppiatore
The glitch engine, and the one design decision worth explaining. It rewrites patterns bar by bar with rotation, decimation and segment swaps, turns single steps into ratchets, and processes the master through a feedback line and a rhythmic gate.
Crucially, it is deterministic: the randomness derives from a seed combined with the bar number, so bar twelve always glitches the same way, today and in a month. Chaos becomes something you can compose with and share, instead of a lucky take you can never get back. Hold GLITCH for a momentary burst, or engage HOLD to run it as a permanent processor. Your own patterns are never modified: the engine works on copies.
Intonarumori
The song arranger. Switch from LIVE to SONG, drag patterns from the library on the left onto the timeline, and build an arrangement. Blocks can be moved, resized from their right edge and removed with a double click. Drone modules and the glitch engine appear as lanes too, so they can be composed rather than only performed.
Sincronizzatore
MIDI clock output, which makes Macchinetta the master of a hardware setup. Press ENABLE MIDI, select the output ports that appear, and switch CLOCK on: PLAY and STOP then drive your external gear as well. A song position message is sent before starting, so hardware aligns to the right bar instead of restarting from the top. The OFFSET control compensates the small discrepancy between audio latency and MIDI latency.
This requires the Web MIDI API, available in Chrome, Edge, Opera and Firefox. Safari does not implement it.
Sharing a patch as a link
Press COPY LINK, in the transport bar or in the arranger toolbar, and the entire state of the machine is packed into the address: grids, knob positions, synth modes, mixer settings, the full arrangement and the glitch seed.
Nothing is uploaded. The state travels in the fragment of the URL, which browsers never send to a server, so a patch link works on static hosting, inside a page, or anywhere a file can sit. Two things a link cannot carry: audio files you loaded from your own disk, and the glitch HOLD state, deliberately left out so a shared patch never opens already falling apart.
Recording
The REC button captures the master output, glitch included, and downloads it as an audio file when you stop. It records what you hear, in real time, so a four-bar loop takes four bars to record.