WretchUp vs Theremin Synth
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.
Theremin Synth
Create unique soundscapes with this multitouch synthesizer. Record, loop, and overdub your creations, then export them as WAV files to share. Experiment with various waveforms and effects for endless sonic possibilities.
- Multitouch synthesis
- Record, loop, and overdub
- Adjustable delay, feedback, and scuzz effects
- Four waveform options
- Export recordings as WAV files
- Offline functionality
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This is a multitouch synth instrument. Play it by touching and swiping the screen, changing the waveforms and sliding the effects to create anything from traditional sci-fi theremin sounds to deep scuzzy soundscapes. Use the looper controls to record, loop and overdub layers. Then if you wish to save or share your recording, hit the download button to send your wav file to other compatible apps like Messages, Email, Dropbox etc. The original Theremin went live in 2014 on the web at femurdesign.com/theremin. Over a million hits later and hundreds of requests for a record button, I have redesigned it. Now the Theremin is ready for you to experiment with. Happy playing! -- SPECIFICATIONS -- • Record, loop and overdub options. • Multitouch allows up to 8 tones to be played simultaneously with your fingers • 3 sliders: delay, feedback and scuzz • 4 waveforms: sine, square, triangle and saw • No internet needed, works both online and offline • Download the loop as a .wav file • Loops can be shared with other apps like Mail, Message and more. • 1000+ installs • Compatible with iOS versions 8 - 10 • Optimized for iPhone, iPad & iPad Pro -- REVIEWS -- Gizmodo "Just mess around! Twiddle those faders! Swipe and click with reckless abandon! Turn the volume all the way up, give the dog a panic fit, and make your neighbours think the street's being invaded by giant cabbage people from planet Zok. Trust me, this will never get old.” Dangerous Minds “New online theremin simulator kind of sounds cooler than the real thing. Check it out and annoy your co-workers.” Mashable “Messing around with this virtual theremin is completely addicting” -- CONTACT -- To find out about my other musical app projects, please go to femurdesign.com and share your loops with me on Facebook and Twitter. Facebook: facebook.com/femurdesign Twitter: @femurdesign For any queries and support contact me here: femurdesign.com/support
Screenshots
Verdict
WretchUp and Theremin Synth both sit at 3.1 stars, but that hides the real split: 91% of WretchUp's written reviews are positive against 64% of Theremin Synth's. WretchUp also leads on update cadence (every 3 weeks vs every 2 months). Theremin Synth's advantage is price ($2.99 vs $4.99). On rating, ratings volume, 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
WretchUp costs $4.99 and Theremin Synth $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 3.1 for WretchUp against 3.2 for Theremin Synth. Both are backed by a comparable volume of ratings — 9 and 6 respectively. Written reviews are what separate them: 91% of WretchUp's written reviews are positive against 64% of Theremin Synth's.
WretchUp ships an update every 3 weeks, Theremin Synth every 2 months. Both last shipped on October 24, 2026.
| Parameter | WretchUp | Theremin Synth |
|---|---|---|
| Price | $4.99 | $2.99 — better |
| Rating | 3.1 (9 ratings) | 3.2 (6 ratings) — better |
| Positive reviews | 90.9% of reviews — better | 63.6% of reviews |
| Number of ratings | 9 — better | 6 |
| Update frequency | Every 3 weeks — better | Every 2 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 11.0 — better | 12.1 |
| Further details — not scored | ||
| Size | 15 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | MoMinstruments GbR | Luke Phillips |
Customer experience
WretchUp
Theremin Synth
In-app purchases
WretchUp
No in-app purchases
Theremin Synth
No in-app purchases









