MelodySlotMachine vs Nulltrack
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
MelodySlotMachine
Create new melody combinations by rearranging variations using slot dials. This AI-powered tool analyzes musical structure to generate new compositions, aiding composers in projects requiring many variations. Explore next-generation music production and consumption.
- Dial-based melody variation selection
- Grid tile operation for timeline visualization
- Melody shuffle via device shake
- Song and part selection
- AI-driven musical structure analysis
- Next-generation music creation
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Melody Slot Machine is an application developed by RIKEN towards the integration of music and AI. You can create new melody combinations by rearranging melody variations using slot dials. When the composer composes melody variations, the structure of the melody is analyzed using a theory of music known as generative theory of tonal music (GTTM). Even if the melody switches to another variation in the middle, the structure will not be disrupted. You can expand the possibilities of composition with Melody Slot Machine. - Dial operation By rotating the dials similar to a slot machine, you can select a melody from multiple variations. The dial scrolls to the left as the performance progresses, and the leftmost dial on the screen represents the score of the performance currently being played. - Grid tile operation The horizontal grid tiles below the dials show the dial changes throughout the song. Swipe up to expand and use the elongated grid tile. - Melody shuffle When you shake your iPhone, all the dials rotate simultaneously, similar to when you pull the lever on a slot machine and stop at a random combination. - Song selection / Part switching You can select a song by pressing the musical note button. For songs containing multiple parts, you can press the button to switch between parts. - Development history The Music Information Intelligence Team, part of the RIKEN Center for Advanced Intelligence Project, is exploring potential new ways of creating and listening to music using AI. The Melody Slot Machine is an example of next-generation music production and consumption in which AI automatically analyzes the structure of a melody and resynthesizes a new melody using the obtained structure. We aim to support composers in projects that require many variations, such as in movies and games. The app is available to the public to gauge the overall interest in such a method of music creation. We ask that users the app who are prompted to fill out a questionnaire to please submit their responses. We plan to add songs in the future. If you are interested in the app and technology, please contact us at the support URL.
Nulltrack
This mobile digital audio workstation offers a unique, grid-based approach to music creation, inspired by classic trackers. It includes built-in synths, a sampler, extensive modulation options, and mixing tools.
- AUv3 plugin support
- Two built-in synthesizers
- Built-in sampler
- Extensive modulation options
- Mixing features with track faders
- Groove tables for swing/playback
- Pattern locking to scales
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Nulltrack! It's null when you start and a track when you finish! Nulltrack is a tracker and digital audio workstation app for your phone. A different way to make music inspired by LSDJ and the Dirtywave M8. Features: AUv3 plugin support - bring your external synths and effects into your track! Two built-in synthesizers -- A versatile two-oscillator Basic Synth and a feature-rich Bass Synth. A built-in sampler -- record your own samples with your phone's microphone, load your own, or use the built-in samples, set loop points, slice, reverse, etc. Modulation -- Modulate nearly anything with LFOs, AHD / ADSR / drum envelopes, velocity, randomness, and key tracking, filter, panning, and more. Mixing Features -- track faders with solo and mute, 13 built-in effects, sidechain compression Sends -- share effects between tracks Customize your swing/playback with groove tables! Lock your patterns to a built-in scale! ...and much more! New to trackers? They're a fast, grid-based way to write music. Try it out! No ads, no subscription, no in-app-purchases, and no account needed.
Screenshots
Verdict
The clearest difference is price: MelodySlotMachine at Free against Nulltrack's $7.99. MelodySlotMachine also leads on iOS requirement (11.4 vs 17.0). On update cadence, ads, in-app purchases 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
MelodySlotMachine is free to download; Nulltrack costs $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.
MelodySlotMachine ships an update weekly, Nulltrack every 9 days. The most recent releases landed on October 11, 2026 and October 18, 2026 respectively.
| Parameter | MelodySlotMachine | Nulltrack |
|---|---|---|
| Price | Free — better | $7.99 |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 1 — better | — |
| Update frequency | Weekly — better | Every 9 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPod — better | iPhone |
| Requires iOS | 11.4 — better | 17.0 |
| Further details — not scored | ||
| Size | 192 MB | 17 MB |
| Age rating | 4+ | 4+ |
| Developer | newforestar co,.ltd | DECTET LLC |
Customer experience
MelodySlotMachine
Nulltrack
In-app purchases
MelodySlotMachine
No in-app purchases
Nulltrack
No in-app purchases









