KORG iM1 vs Zeeon synth
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
KORG iM1
This app faithfully reproduces the legendary M1 synthesizer, offering its iconic sounds and expanded features for modern music creation. It provides a vast library of presets and intuitive performance tools, making it accessible to both experienced musicians and beginners.
- Faithful reproduction of original M1 sound
- Expanded filter resonance and 18 effects
- Gigantic library of 3,300 sounds
- Intuitive KAOSS pad for performance
- Smart Sound Browser for quick sound selection
- Compatible with KORG Gadget
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A complete reproduction - and more - of the legendary M1 that defined an era. Mobile Digital Synthesizer for the iPad. ● Selected by Apple as "App Store Best of 2015" ● Ranked #1 on the App Store on Top Paid Music category in more than 20 countries! (15/5/27) Since it went on sale in 1988 the legendary M1 music workstation rapidly achieved record-breaking sales, becoming a mainstay of the music scene from the late 1980s and beyond. The common element of electronic instruments that have left their name in history is that they had a unique sound that was difficult if not impossible to replicate. Sounds such as the “M1 Piano” is instantly recognizable and have appeared on countless hit records over many years, and yet these are sounds that could only be produced by the M1. And that’s what you can now have on your iPad! ● A faithful reproduction of the original M1 Sound The PCM data provides the library of the original M1. For the hardware, we analyzed the circuit diagram of the original design, and completely replicated it in software down to the last detailed parameters. Engineers with an exhaustive knowledge of the M1 made careful adjustments in order to obtain the sound of the original unit, something that cannot be obtained simply by sampling the original sounds. ● A continued evolution of the M1 Not content with simply reproducing the original, iM1 provides further evolutionary developments. Synth parts now have the Filter Resonance that was requested at the time of the original. The effect parts, originally consisting of only two effects, have been powered-up to 18 effects. The user interface has also been refreshed with additions such as a KAOSS pad. iM1 is the ultimate version of the KORG M1. ● A gigantic library encompassing 3,300 sounds and 34 cards* In addition to all 19 of the ROM cards originally released for the M1, iM1 also covers the sounds of the M1EX which expanded the internal PCM of the M1, as well as the sounds of the T-series which appeared as an evolution of the M1. There’s also “BEST OF M1”, a selection of 100 great M1 programs. The new “Smart Sound Browser” makes it quick to find the desired sound. You can also view the sounds ranked by how often they are selected by iM1 users around the world. *with all the expansion card installed via in-app purchase ● KAOSS pad lets anybody perform iM1 features a KAOSS pad from the popular KAOSSILATOR, allowing you to perform intuitively just by touching the screen. By using the dual KAOSS pads to play phrases or adjust the sound, even people who are not accustomed to keyboard instruments or knowledgeable about synthesizers can enjoy performing the iM1. There’s also a conventional keyboard, as well as the “Smart Keyboard”, which lets you specify a scale setting and play phrases with a single finger. ● Use with KORG Gadget for song production iM1 can be used together with Gadget, the music production DAW app that won the App Store Best App of 2014 award in Japan. If both apps are installed, you can use iM1 as a sound module within Gadget, taking advantage of the program sounds in iM1 for music production. iM1 also supports Audiobus and Inter-App Audio, so it can also be used for GarageBand etc. ● Connect a MIDI keyboard and use as a sound module In addition to enjoying iM1 on its own, you can connect a USB MIDI keyboard* via a Lightning adaptor and play the iM1 as an external sound module. You can easily take along an even more powerful workstation sound module as part of your iPad-based compact mobile system. *microKEY, nanoKEY etc. ● Interchangeable with the KORG Legacy Collection and the original M1 Sounds that you create in iM1 can be sent from your iPad via iTunes to a Mac/PC. If you have the Legacy Collection M1, you can use those sounds in a DAW. More info at korg.com
Zeeon synth
This app is a virtual analog synthesizer that recreates the sound and feel of classic hardware. It features a detailed circuit-modeling engine, powerful modulation, and multiple filter models for rich, organic soundscapes. Explore a vast array of presets and expand your sonic palette with additional sound banks.
- Circuit-modeling engine
- Powerful modulation matrix
- Dual oscillators with variable waveforms
- Multiple filter models
- Built-in effects unit
- Audio Unit v3 support
- Polyphonic step sequencer
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Zeeon is a virtual-analog synthesizer built on a deeply detailed circuit-modeling engine. We’ve studied classic and modern analog synths to uncover what gives them their unmistakable character and recreated that essence with precision. The result is a unique instrument that delivers the warmth, movement, and organic depth of true hardware. While many emulations sound flat, Zeeon breathes. Every note is alive, with tight lows and shimmering highs. All audio and modulation are processed at 176 kHz (4× oversampling) for uncompromised quality across the entire spectrum. “Desktop-class sound engine … fidelity of this analog emulation goes beyond everything else on iOS.” – App Store review Features • Audio Unit v3 and standalone application with a simple polyphonic step sequencer • Powerful modulation matrix offering self-modulation and cross-layer modulation, 8 modulation slots, 17 signal sources and 41 targets available, both from modulation modules and audio signal path. This takes Zeeon into semi-modular territory. Imagine oscillator waveform, panning, filter cutoff, resonance or LP-HP mode modulated by oscillators or another layer! • 2 oscillators with continuously variable waveforms, hard-sync and sub-oscillator. Carefully simulated analog drift and PSU influence. • Filter: 3 models available: Transistor ladder low pass, OTA cascade low pass and State Variable Filter with continuously variable LP-HP + BP mode. • 2 low frequency oscillators and envelope generators per voice. • Overdrive: diode clipper, transistor saturation, wave folder, pre and post filter. • Up to 2 layers per voice. Layers can modulate each other. • Effects unit: Circuit modelled BBD chorus, bass booster, zero-delay Phaser, Stereo delay and Reverb. • 280 presets and Tutorials bank. 3 additional banks available as IAPs. Full manual and audio demos available at the BeepStreet website.
Screenshots
Verdict
The clearest difference is price: Zeeon synth at $14.99 against KORG iM1's $29.99. Zeeon synth also leads on update cadence (every 2 months vs every 7 months). KORG iM1's advantage is ratings volume (1K vs 209) and iOS requirement (12.0 vs 15.6). On rating, review sentiment, ads and in-app purchases 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
KORG iM1 costs $29.99 and Zeeon synth $14.99 up front. KORG iM1 sells 2 one-off in-app purchases and Zeeon synth sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 4.7 for KORG iM1 against 4.8 for Zeeon synth. Both are backed by a comparable volume of ratings — 1K and 209 respectively. Written reviews are what separate them: 82% of KORG iM1's written reviews are positive against 76% of Zeeon synth's.
KORG iM1 ships an update every 7 months, Zeeon synth every 2 months. The most recent releases landed on October 26, 2026 and October 24, 2026 respectively.
| Parameter | KORG iM1 | Zeeon synth |
|---|---|---|
| Price | $29.99 | $14.99 — better |
| Rating | 4.7 (1K ratings) | 4.8 (209 ratings) — better |
| Positive reviews | 81.5% of reviews — better | 76.0% of reviews |
| Number of ratings | 1K — better | 209 |
| Update frequency | Every 7 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 15.6 |
| Further details — not scored | ||
| Size | 200 MB | 27 MB |
| Age rating | 4+ | 4+ |
| Developer | KORG INC. | BeepStreet |
Customer experience
KORG iM1
Zeeon synth
User reviews
KORG iM1
From 1K App Store ratingsWhat we love
- 👍 Authentic M1 sound reproduction
- 💰 Great value for money
- 🎹 Faithful recreation of the original hardware
- 🎨 Powerful sound customization options
- 🔗 Works well with MIDI controllers
Room to improve
- 🐛 Occasional crashes or stability issues
- 🔇 Low output volume compared to other apps
- 🤔 Confusing UI for patch editing and saving
- 🔴 Missing AUv3 support for integration with DAWs
Zeeon synth
From 209 App Store ratingsWhat we love
- 🎨 Excellent sound quality
- 🎹 Intuitive and well-designed interface
- 🔧 Flexible and deep sound design capabilities
- 💻 Seamless integration as an AUv3 plugin
- 🎚️ Smooth and responsive controls
Room to improve
- 🐛 Stability issues, crashes on some devices
- 🔌 Compatibility problems with newer iOS versions
- 📂 Preset management could be improved
- 🔀 Lack of MIDI learn and sequencer features
- 🖥️ UI scaling issues on larger iPad displays
Bugs and requests
KORG iM1
Reported bugs
3 issues- Disappearing or missing purchased sound cards
- Bluetooth MIDI connectivity issues
- Compatibility problems with certain iOS versions or devices
Requested features
4 requests- Add AUv3 support for better DAW integration
- Improve preset management and saving capabilities
- Increase master volume control options
- Expand sound library with more cards/expansions
Zeeon synth
Reported bugs
4 issues- Preset settings not retained after app restart
- Synth reverts to default settings when reopening Logic Pro project
- Crashes and freezes on certain iOS 14+ devices
- Inability to access in-app purchases from within the app
Requested features
5 requests- Add MIDI learn functionality
- Implement a more robust preset management system
- Include a built-in sequencer with save/load capabilities
- Improve UI scaling and layout for larger iPad screens
- Provide better integration with inter-app audio and Audiobus
In-app purchases
KORG iM1
- M1 Cards Pack$4.99
- T1 Cards Pack$4.99
Zeeon synth
- OI - Exploration Vol. 1$3.99
- BB Z-Space$4.99
- BB Synthwave$4.99









