Comparison

Theremin I/O vs Polybeep

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

Head to head
About

Theremin I/O

Transform your iPhone into a touchless musical instrument using your camera and flash. Control sound generation by hand proximity, with options for scales, sound presets, and effects. An in-app purchase enables MIDI controller functionality.

Highlights
  • Touchless instrument control via camera
  • Adjustable scales and harmony quantization
  • Multiple sound presets with effects
  • MIDI controller functionality (in-app purchase)
  • Interactive tutorial overlay
Features
Currently charting
Read full description

Play with light – Theremin I/O turns your iPhone into a touchless music instrument. It uses your camera and flash to measure the distance to your hand, this signal is then processed by a synthesizer to generate a tone. Features: • Old-school synthesizer • Constrain input to scales (harmony quantization) • 8 sound presets with effect controls • 50+ scale presets • Use as a MIDI controller (requires in-app purchase) • Learn fast with the tutorial overlay For more information visit http://theremin.io

About

Polybeep

Create unique music with a polyrhythmic sound machine. Record or load samples, arrange them into looping shapes, and apply various effects. MIDI input is supported, and songs can be exported as WAV files.

Highlights
  • Polyrhythmic sound generation
  • Record microphone audio
  • Load sample files
  • Looping shape arrangement
  • Extensive audio effects
  • MIDI input support
  • Export to WAV
Features
Read full description

From the creators of DefleMask and Minimic, introducing Polybeep, a magnificent polyrhythmic sound machine designed to unlock your creativity. We even prepared a built-in tutorial to get you started. With aesthetically pleasing colors and design alongside unmatched visual feedback, you can really feel the beeping beeps and the poly rhythms. Yes, you can set up polyrhythms as easy as 3-4-5. You can record sounds directly from your microphone or load sample files. There’s some magic to make them sound great. Arrange the sounds into up to 6 looping shapes that can be configured as polygons of 3~16 vertices, then tweak their effects (delay, reverb, EQ, panning, chorus, and more), make a sequence of many melodies, and you’ll have a song in no time! You can even tap to change the tempo based on a rhythmic pulse. MIDI device input is as well supported! MIDI output coming soon! (notes, sync) macOS version is also available! Polybeep has been designed with a touch screen in mind from day one but it works perfectly fine on computers. When ready, you can save your songs and export them to wav files. We’d love to hear the songs that you come up with!

Screenshots

Theremin I/O3 screens
Polybeep4 screens

Verdict

The call

The clearest difference is rating: Polybeep at 4.7 against Theremin I/O's 4.0. Polybeep also leads on in-app purchases (none vs 1) and update cadence (fortnightly vs every 24 months). Theremin I/O's advantage is review sentiment (77% vs 50%) and chart position (#163 vs unranked). On ratings volume, ads, monetization model 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

Theremin I/O costs $2.99 and Polybeep $4.99 up front. Theremin I/O sells 1 one-off in-app purchase. Polybeep asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Polybeep holds the better App Store score, 4.7 against 4.0. Both are backed by a comparable volume of ratings — 5 and 3 respectively. Written reviews complicate that: 77% of Theremin I/O's written reviews are positive against 50% of Polybeep's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Theremin I/O ships an update every 24 months, Polybeep fortnightly. The most recent releases landed on October 12, 2026 and September 30, 2026 respectively.

Scorecard7 real differences · 4 level
Theremin I/O versus Polybeep: the parameters behind the verdict, then further details
ParameterTheremin I/OPolybeep
Price$2.99 — better$4.99
Rating4.0 (5 ratings)4.7 (3 ratings) — better
Positive reviews76.9% of reviews — better50.0% of reviews
Number of ratings5 — better3
Update frequencyEvery 24 monthsFortnightly — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidPaid
Best chart rank#163 — better—
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS8.0 — better12.0
Further details — not scored
Size18 MB101 MB
Age rating+44+
DeveloperFFFF00 Agents ABLeonardo Demartino

Customer experience

Theremin I/O

All ratings5 ratings
Positive60.0%
Neutral20.0%
Negative20.0%
Written reviews13 reviews
Positive76.9%
Neutral15.4%
Negative7.7%

Polybeep

All ratings3 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

In-app purchases

1 purchases

Theremin I/O

One-time1
  • Network MIDI$5.99
None

Polybeep

No in-app purchases

Questions

Is Theremin I/O free?
Theremin I/O costs $2.99, and also offers in-app purchases.
Is Polybeep free?
Polybeep costs $4.99, with no in-app purchases.
Which has better reviews, Theremin I/O or Polybeep?
Polybeep is rated higher. Theremin I/O averages 4.0 out of 5 from 5 ratings, while Polybeep averages 4.7 from 3 ratings.
Do Theremin I/O or Polybeep have ads?
Neither Theremin I/O nor Polybeep shows ads.
Which is updated more often, Theremin I/O or Polybeep?
Theremin I/O ships an update every 24 months, and Polybeep fortnightly. Most recently, Theremin I/O was updated on October 12, 2026 and Polybeep on September 30, 2026.

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