VOSIS vs Holon
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
VOSIS
This app transforms image data into sound, allowing for unique musical compositions and experimental sound design. It offers control over pitch, timbre, and envelopes to create shape-timbre relationships from visual input.
- Image sonification
- Visual music composition
- Experimental sound design
- Pixel luminance audification
- Shape-timbre relationships
- Adjustable pitch and timbre
- ADSR envelope control
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VOSIS is a synthesizer combining audification of greyscale pixel data with several image filters. It is a tool for image sonification, visual music composition, and experimental sound design. The audification of pixel luminance values creates shape-timbre relationships. Pixel scan rate is controlled in terms of note interval, octave, and scale to give varying pitch between image regions. The ADSR envelope allows one to play images as a non-linear sequence of pitches with varying wavetable/timbre. For more features including presets and unlimited recording see VOSIS Pro. Visit vosis.app for sound example, demo videos, and user guide!
Holon
This app transforms your movement through cities into a dynamic, real-time musical score. It uses your physical location and activity to generate interactive synth music, encouraging outdoor exploration and turning listeners into performers.
- Human-powered music generation
- Encourages outdoor activity
- Zero UI for minimal distraction
- Environmentally responsive music
- Real-time synth music creation
- Optional AirPods and Apple Watch integration
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Holon makes the city your instrument. It turns your movement in the environment into a synthetic, interactive score that reflects your context, supports your activities and alerts you to changes in the surrounding area. Holon uses physical computing and a geospatial dataset to synthesize music on the iPhone in real time from your data - no streaming or AI involved, just pure DSP and logic. What Holon Does: * Human powered music. Every action generates dynamic, improvised synth music in real time. * Encourages outdoor activities. Holon doesn’t work in your apartment or by shaking your phone around. Move through streets, parks, and transit systems to make the music happen. * Stays out of your way. Zero UI means less screen time, no distractions. * Uses places and spaces to modify the music you make. The environment isn’t background - it’s the score. * The more and further you move, the more things happen in the music. Use your musical agency instead of skipping and swiping. Why Holon Exists: Music has been reduced to a commodity and a background activity for consumerism. Holon isn’t here to help you chill when you swipe, scroll and buy more stuff, or improve your focus when working for the Man. Holon is here to break away from the static, one-way relationship of streaming services and to put the human in the loop - yourself. Forget emoting celebrities with their false sincerity, throw overproduced passive soundscapes and statistical algorithms on the dung heap of history. Holon turns listeners into performers and unlocks the musical potential of places. How to Use: * Go outside - Holon needs space to function, just like you. Different districts, parks, bridges, shops, street furniture - all contribute to the musical output. Strolling around your apartment or shaking your phone won’t do. * Put the phone in your pocket or on your dashboard. * Walk, run, drive - the world is now the interface, space is the machine. * Use the big button in the middle to power Holon off when not in use - Auditory AR can be a battery-intensive process! * Optional Apple AirPods support for head-controlled musical interactions! * Optional Apple Watch support for heart rate-synced music (biofeedback) *the Watch app may take a moment to install* Requirements: * Available in over 1000 regions in more than 100 countries. * Check coverage or request a new area at holonic.systems/holon. * Best experienced with headphones. Ensure adequate battery level for extended use. * A data plan is required to access our geospatial engine but use of data is low. Holon: Become part of the circuit and… Become Sound™
Screenshots
Verdict
The clearest difference is in-app purchases: VOSIS at none against Holon's 2. VOSIS also leads on review sentiment (86% vs 75%). Holon's advantage is rating (4.5 vs 4.2) and update cadence (every 3 months vs every 8 months). On price, ratings volume, 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. Holon sells 2 one-off in-app purchases. VOSIS asks for nothing beyond the download.
Holon holds the better App Store score, 4.5 against 4.2. Both are backed by a comparable volume of ratings — 5 and 14 respectively. Written reviews complicate that: 86% of VOSIS's written reviews are positive against 75% of Holon's, so the app with the better star average is not the one people write more warmly about.
VOSIS ships an update every 8 months, Holon every 3 months. The most recent releases landed on October 26, 2026 and October 19, 2026 respectively.
| Parameter | VOSIS | Holon |
|---|---|---|
| Price | Free | Free |
| Rating | 4.2 (5 ratings) | 4.5 (14 ratings) — better |
| Positive reviews | 85.7% of reviews — better | 75.0% of reviews |
| Number of ratings | 5 | 14 — better |
| Update frequency | Every 8 months | Every 3 months — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod, Apple Watch — better |
| Requires iOS | 13.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 11 MB | 144 MB |
| Age rating | 4+ | 4+ |
| Developer | Life Orange LLC | Holonic Systems Oy |
Customer experience
VOSIS
Holon
In-app purchases
VOSIS
No in-app purchases
Holon
- Apple Watch supportFree
- Movesense SupportFree









