WretchUp vs Krill Synthesizer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
WretchUp
This app offers a unique audio manipulation experience, allowing users to create sonic mayhem with pitch-shifted delays, filters, and sampling. It's designed for live performance and studio use, enabling musicians and sound enthusiasts to generate wild noises and unique effects.
- Pitch-shifted delay with feedback and filter
- Live performance-oriented controls
- Gesture-based play
- Record vocals and instruments
- Sample and manipulate loops
- Inter-App-Audio and Audiobus support
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An effect instrument anyone can play - sonic anarchy in the palm of your hand. iOS Mars: "Barely controlled chaos“, "sonic extremes“, "well suited for live use“ Music App Blog: "if you like the occasional dose of sonic mayhem, then this is an app that will let you make it" WretchUp is the sonic instrument from the imagination of Mouse on Mars Instruments. Used by the duo in their live performances, it's a playable effect inspired by analog hardware. Sing into it, speak into it, plug in an instrument, sample sounds, and then make sonic mayhem. It's been tested in Mouse on Mars' live shows and used in studio albums. But now it's available to anyone - whether you're a musician wanting to create unique sounds or you just want to make some wild noises and frighten friends and enemies. // FEATURES - Pitch-shifted delay with feedback and filter - Unique controls, designed to be used in live performance and tested onstage - Play with gestures, even without looking closely at the screen - Record vocals or instruments from the built-in mic or another input - Sample loops and change their speed - Adjust the feedback loop, pitch, and filter for unique sounds - Make inputs by holding down your finger, or lock input for continuous sampling - Inter-App-Audio supported - Audiobus supported www.mouseonmars.com/mominstruments Features artwork by Rupert Smyth. Pure Data-based, open source patch created by Florian Grote and Peter Kirn with Mouse on Mars. App design by Oliver Greschke. Powered by free and open source software libpd. Note: like all mic-based effects, you need to enable microphone input. If you accidentally did not allow mic input, you can allow later via: Device settings, WretchUp, Data settings, Microphone, allow mic input.
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 rating: Krill Synthesizer at 5.0 against WretchUp's 3.1. Krill Synthesizer also leads on update cadence (weekly vs every 3 weeks) and review sentiment (100% vs 91%). WretchUp's advantage is price ($4.99 vs $11.99). On ratings volume, ads, in-app purchases and monetization model 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
WretchUp costs $4.99 and Krill Synthesizer $11.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Krill Synthesizer holds the better App Store score, 5.0 against 3.1. Both are backed by a comparable volume of ratings — 9 and 6 respectively. Written reviews point the same way: 91% of WretchUp's written reviews are positive against 100% of Krill Synthesizer's.
WretchUp ships an update every 3 weeks, Krill Synthesizer weekly. The most recent releases landed on October 3, 2026 and October 11, 2026 respectively.
| Parameter | WretchUp | Krill Synthesizer |
|---|---|---|
| Price | $4.99 — better | $11.99 |
| Rating | 3.1 (9 ratings) | 5.0 (6 ratings) — better |
| Positive reviews | 90.9% of reviews | 100.0% of reviews — better |
| Number of ratings | 9 — better | 6 |
| Update frequency | Every 3 weeks | Weekly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 11.0 | 11.0 |
| Further details — not scored | ||
| Size | 15 MB | 8 MB |
| Age rating | 4+ | 4+ |
| Developer | MoMinstruments GbR | Genuine Soundware |
Customer experience
WretchUp
Krill Synthesizer
In-app purchases
WretchUp
No in-app purchases
Krill Synthesizer
No in-app purchases









