Zeeon synth vs Krill Synthesizer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
Krill Synthesizer
This virtual analog polyphonic synthesizer offers a streamlined interface for creating quick synth sounds on iPad. It features two oscillators, an LFO, a low-pass filter, two envelopes, and stereo effects, all accessible from a single screen.
- Virtual analog polyphonic synthesizer
- Single-screen interface
- Two oscillators
- One LFO
- Low-pass filter
- Stereo chorus and ping-pong delay
- 64 presets
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The GSi Krill Synthesizer was born from a design originally conceived to work as a mono synthesizer on an embedded processor (RP2040), then it was modified to be polyphonic for a more powerful processor (ARM H7) and finally we thought it would be perfect as a AUv3 for iPad, for those quick and dirty synth sounds you sometimes need without getting lost in endless parameter navigation and menu diving. So here it is, just one screen, one knob - one function, what you see is what you get. Two oscillators, one LFO, one low pass filter, two envelopes, stereo chorus, ping-pong delay, 64 presets. Have fun!
Screenshots
Verdict
The clearest difference is in-app purchases: Krill Synthesizer at none against Zeeon synth's 3. Krill Synthesizer also leads on update cadence (weekly vs every 2 months) and review sentiment (100% vs 76%). Zeeon synth's advantage is ratings volume (209 vs 6). 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
Zeeon synth costs $14.99 and Krill Synthesizer $11.99 up front. Zeeon synth sells 3 one-off in-app purchases. Krill Synthesizer asks for nothing beyond the download.
Krill Synthesizer holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Zeeon synth has 209 ratings behind it against 6, so its average is the more settled of the two. Written reviews point the same way: 76% of Zeeon synth's written reviews are positive against 100% of Krill Synthesizer's.
Zeeon synth ships an update every 2 months, Krill Synthesizer weekly. The most recent releases landed on October 24, 2026 and October 11, 2026 respectively.
| Parameter | Zeeon synth | Krill Synthesizer |
|---|---|---|
| Price | $14.99 | $11.99 — better |
| Rating | 4.8 (209 ratings) | 5.0 (6 ratings) — better |
| Positive reviews | 76.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 209 — better | 6 |
| Update frequency | Every 2 months | Weekly — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.6 | 11.0 — better |
| Further details — not scored | ||
| Size | 27 MB | 8 MB |
| Age rating | 4+ | 4+ |
| Developer | BeepStreet | Genuine Soundware |
Customer experience
Zeeon synth
Krill Synthesizer
Bugs and requests
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
Krill Synthesizer
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Zeeon synth
- OI - Exploration Vol. 1$3.99
- BB Z-Space$4.99
- BB Synthwave$4.99
Krill Synthesizer
No in-app purchases









