1981 FM vs ARPJAM Player
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
1981 FM
This app generates complete, unique musical tracks using chaotic mathematical principles. It offers various styles, modes, and keys, with customizable FM synth sounds and effects. Tracks can be recreated using seeds and exported via MIDI.
- Chaos-driven track generation
- Four-operator FM synth engine
- Multiple musical styles and modes
- MIDI export and input
- Customizable effects (chorus, delay, reverb)
- Offline functionality
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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.
ARPJAM Player
This app allows you to queue music tracks and set individual playback durations. It automatically fades out the current track and transitions to the next, ensuring consistent loudness and background playback. Explore a library of published tracks or import your own.
- Queue and time music tracks
- Automatic track fading and transition
- Matched loudness for consistent volume
- Background playback with screen off
- Browse and import music library
- Dynamic music generation engine
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ARPJAM Player is a device for leaving your JAMs running. Line up the JAMs you want to hear and give each one a play time. When the time is up it fades out on its own and hands over to the next one. Nothing else to do. ■ For as long as you like Play times run from one minute to twelve hours, set on a reel. Leave one JAM running all afternoon, or cut them short and keep moving. It is built for the kind of listening that lasts a whole opening shift. ■ Matched loudness JAMs vary in level. Each one is measured once when you add it, and matched on playback — the loud ones come down, the quiet ones come up. No sudden jump when the next one starts. Nothing chases the level while the music plays, so the volume never moves mid-performance. ■ With the screen off Background playback is supported. Lock the screen and it keeps going. Play, pause and skip from the Lock Screen or Control Center. ■ JAM Library Open the JAM Library from inside the app and add published JAMs directly. Browse by genre and see the artist, the notes, the BPM and the key. Official JAMs and submitted JAMs sit side by side. You can also import .arpjam files stored on your device, including files written by the earlier ARPJAM. ■ It never plays the same way twice The ARPJAM engine is not playing back a fixed score. It builds the performance as it goes, following rules. The same JAM sounds different every time you play it, so it does not become a loop you get tired of — even after hours. Same engine as ARPJAM Studio. ■ Made for · Saunas, spas, treatment rooms · Cafes, shops, galleries · Working, studying, winding down · Exhibitions and installations — — ARPJAM Player does not create JAMs. To make them, use ARPJAM Studio.
Screenshots
Verdict
The clearest difference is in-app purchases: ARPJAM Player at none against 1981 FM's 1. ARPJAM Player also leads on update cadence (every 2 days vs every 2 weeks). 1981 FM's advantage is ratings volume (3 vs 1). On price, rating, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. 1981 FM sells 1 one-off in-app purchase. ARPJAM Player asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for 1981 FM against 5.0 for ARPJAM Player. Both are backed by a comparable volume of ratings — 3 and 1 respectively.
1981 FM ships an update every 2 weeks, ARPJAM Player every 2 days. Both last shipped on October 24, 2026.
| Parameter | 1981 FM | ARPJAM Player |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (3 ratings) | 5.0 (1 ratings) |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 3 — better | 1 |
| Update frequency | Every 2 weeks | Every 2 days — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 15 MB | 78 MB |
| Age rating | 4+ | 4+ |
| Developer | Soft Brew Mobile | Takashi Tsunoda |
Customer experience
1981 FM
ARPJAM Player
In-app purchases
1981 FM
- AUv3 Unlock$2.99
ARPJAM Player
No in-app purchases









