Concentric Rhythm vs Polly
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Concentric Rhythm
Generate, develop, and explore musical patterns using geometric transformations and simple processes. Visualize musical timelines as circles for intuitive manipulation and create complex rhythms and melodies. Connect to other MIDI-compatible apps and devices.
- Geometric pattern generation
- Circular musical timeline visualization
- Melodic line tools (random-walk, scale-based)
- Rhythmic line generation (cross-rhythms, Euclidean algorithm)
- MIDI output to other apps/devices
- Visualizations of polyrhythms
Read full descriptionHide full description
Concentric Rhythm is an interactive tool for generating, developing, and exploring musical patterns. It uses geometric transformations and many other simple processes to create, develop, and evolve music. The looping musical timeline is visualized as a circle, which allows you to treat musical patterns as concentric shapes. This makes performing geometric transformations such as rotations, reflections and folding very natural and intuitive. It also provides tools for melodic lines such as random-walk generation and scale-based inversion and transposition. You can generate rhythmic lines using cross-rhythms or the Euclidean algorithm, and allows for great visualisations of complex polyrhythms. Concentric Rhythm now allows you to assign each pattern to a different MIDI channel and send your results to other MIDI compatible apps or devices. Concentric Rhythm was originally developed as a new way to improvise electronic music, but it is also a great tool experimenting with and developing musical material, or just for casually playing with music in a unique, hands-on, way. Many of the ideas here were inspired by the book ‘The Geometry of Musical Rhythm’ and this app is a powerful tool for anyone who is interested in exploring these ideas. But at the same time is easy enough to use that anyone (even with no musical or mathematical background) can make interesting musical patterns and think about the musical world a little differently. Note: There are known compatibility issues when used with AUM, especially on iOS 14
Polly
Explore complex rhythms with a versatile metronome app. It offers five tracks for accents, subdivisions, polyrhythms, and hypertuplets, with options to mute tracks for customized assistance. Designed for accessibility, it supports VoiceOver and offers stereo or mono audio.
- Polyrhythm exploration
- Five customizable tracks
- Accent and subdivision support
- VoiceOver compatibility
- Background audio playback
- MIDI output for DAWs
Read full descriptionHide full description
Polly is designed as a polyrhythm explorer, and also works great as a standard metronome! Use Polly's five tracks for: • Accents • Subdivisions • Polyrhythms • Hypertuplets Each track can be muted, so Polly can provide as much or as little help as you want. Polly is accessible, providing: • Voiceover support • Accessible color theme • Stereo or Mono audio Polly supports your iPhone, iPad, and Apple Silicon Mac with: • Background use • Light and Dark modes • Bluetooth Audio • Keyboard shortcuts • Multi-tasking support MIDI Support • Connect Polly on your iOS or iPadOS device to your computer to drive drum kits in your computer's digital audio workstation software • Use Polly on your Apple Silicon Mac to send General MIDI Percussion to your digital audio workstation drum kits • Use Polly to drive MIDI drum machines
Screenshots
Verdict
The clearest difference is in-app purchases: Polly at none against Concentric Rhythm's 1. Polly also leads on rating (5.0 vs 4.7) and review sentiment (100% vs 80%). Concentric Rhythm's advantage is update cadence (every 2 weeks vs every 9 months) and ratings volume (43 vs 2). On 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
Concentric Rhythm costs $3.99 and Polly $0.99 up front. Concentric Rhythm sells 1 one-off in-app purchase. Polly asks for nothing beyond the download.
Polly holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Concentric Rhythm has 43 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 80% of Concentric Rhythm's written reviews are positive against 100% of Polly's.
Concentric Rhythm ships an update every 2 weeks, Polly every 9 months. The most recent releases landed on October 17, 2026 and October 16, 2026 respectively.
| Parameter | Concentric Rhythm | Polly |
|---|---|---|
| Price | $3.99 | $0.99 — better |
| Rating | 4.7 (43 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 80.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 43 — better | 2 |
| Update frequency | Every 2 weeks — better | Every 9 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 10.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 44 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Jeff Holtzkener | 591 Group Ltd. |
Customer experience
Concentric Rhythm
Polly
In-app purchases
Concentric Rhythm
- MIDI Send$4.99
Polly
No in-app purchases









