1981 FM: 80s Track Generator

Three chaotic attractors write the music; a policy that learns as it goes keeps what works. Full 64-bar tracks, never the same twice. Free app, one-time AUv3 unlock.

1981 FM writes complete tracks. Press generate and you get 64 bars with an intro, verses, choruses, a break and an outro, played by a four-operator FM synth. Lead, bass, arp, pad and a drum machine, through chorus, delay and reverb.

Nothing is sampled. Every note is made on the fly and no two tracks come out the same.

The music comes from chaos maths. A Lorenz attractor shapes the melody, rhythm and mood. A Hénon map keeps the arpeggio moving. A logistic map handles the drum fills: turn it down and they repeat every bar, turn it up and they never do.

Chaos on its own is noise, so a small model filters it. It gets rewarded for consonant intervals and practises over the chord changes before it writes anything. The CHAOS / POLICY slider decides how much say each one gets.

Ten styles, and they are properly different. Funk plays a 16th-note slap line with ghost notes between the backbeats. Bebop walks the bass and puts the ride in charge of the time. Bossa runs a clave. Space strips the kit back to a pulse.

Every track is built from its seed. Write the seed down and you can have that exact track again, note for note, whenever you want it.

You can play over it, too. The pads are the notes of the song's key rather than a piano keyboard, so nothing you touch is wrong, and the sixteen-step lane runs in time with the song and follows your host. Both play any part you like: lead, bass, arp or pad, through that part's sound and out on its MIDI channel. Choose which sections the lane plays in - just the choruses, say - and preview it on its own without starting the song.

Turn on RADIO and it keeps playing, picking a new key, mode, style and tempo for each track.

You also get:

• 10 styles, 6 modes, 12 keys, tempo and density • Four-operator FM engine, 6 algorithms, 11 presets, random patch • Five-part mixer, chorus, delay, plate reverb and filter • A PLAY panel: pads in the song's own key, and a 16-step lane running in time with the song and only in the sections you pick • MIDI in, so your keyboard plays whichever part you have selected • MIDI export: five tracks, one per part • Live spectrum, waveform and a view of the chaos engine at work

Two Audio Units, an instrument and a MIDI processor. Each part sends on its own MIDI channel, drums on 10, so one instance can drive five instruments. The MIDI version passes your keyboard through instead of swallowing it. Both follow your host's tempo and transport. One install registers both.

The app is free and nothing in it is held back. Using the Audio Units inside other apps is a one-time purchase, and each AUv3 session plays for two minutes first so you can try them properly.

No account, no ads, no subscription. Works offline.