Comparison

Concentric Rhythm vs Polly

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read 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

About

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.

Highlights
  • Polyrhythm exploration
  • Five customizable tracks
  • Accent and subdivision support
  • VoiceOver compatibility
  • Background audio playback
  • MIDI output for DAWs
Features
Read 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

Concentric Rhythm4 screens
Polly3 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard8 real differences · 2 level
Concentric Rhythm versus Polly: the parameters behind the verdict, then further details
ParameterConcentric RhythmPolly
Price$3.99$0.99 — better
Rating4.7 (43 ratings)5.0 (2 ratings) — better
Positive reviews80.0% of reviews100.0% of reviews — better
Number of ratings43 — better2
Update frequencyEvery 2 weeks — betterEvery 9 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS10.0 — better16.0
Further details — not scored
Size44 MB5 MB
Age rating4+4+
DeveloperJeff Holtzkener591 Group Ltd.

Customer experience

Concentric Rhythm

All ratings43 ratings
Positive90.7%
Neutral4.7%
Negative4.7%
Written reviews30 reviews
Positive80.0%
Neutral10.0%
Negative10.0%

Polly

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

1 purchases

Concentric Rhythm

One-time1
  • MIDI Send$4.99
None

Polly

No in-app purchases

Questions

Is Concentric Rhythm free?
Concentric Rhythm costs $3.99, and also offers in-app purchases.
Is Polly free?
Polly costs $0.99, with no in-app purchases.
Which has better reviews, Concentric Rhythm or Polly?
Polly is rated higher. Concentric Rhythm averages 4.7 out of 5 from 43 ratings, while Polly averages 5.0 from 2 ratings.
Do Concentric Rhythm or Polly have ads?
Neither Concentric Rhythm nor Polly shows ads.
Which is updated more often, Concentric Rhythm or Polly?
Concentric Rhythm ships an update every 2 weeks, and Polly every 9 months. Most recently, Concentric Rhythm was updated on October 17, 2026 and Polly on October 16, 2026.

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