# Theremin I/O — user reviews > 13 indexed App Store user reviews of Theremin I/O by FFFF00 Agents AB, rated 4.00/5 from 5 ratings. - Source: https://appshunter.io/ios/app/theremin-io/id669456913/reviews - App overview in markdown: https://appshunter.io/ios/app/theremin-io/id669456913.md - Rating breakdown: 5★ 3 · 4★ 0 · 3★ 1 · 2★ 1 · 1★ 0 ## Most critical reviews (10 lowest-rated) ### 1/5 — Issue with calibration *2014-10-01* I checked, and my phone allows this app to use the camera, but it could never calibrate. **Developer response:** Hi, I know this is several years late but Apple just started allowing Developers to respond to reviews. If you still need help with the app send me an email at johan@yellowagents.com and I'll do my best to assist you! ### 3/5 — Sounds *2018-10-29* I have no access to change sounds. The bottom shows up for half a second and then goes blank. Where do I change sounds? Pretty cool how it works though. It’s awesome. Just love to have other sounds. ### 3/5 — Interesting, but MIDI upgrade expensive *2013-11-08* Kinda fun,when it works. Calibration and use us a little cumbersome and the sounds are actually not very good (have a listen to "Bebot" for top-notch synth/theremin sounds). But definitely interesting and has potential. Oh, and $8.99 for MIDI upgrade??!! Lol. Worth the intro price maybe, but I wouldn't pay more than a buck or two, max, for this. ### 4/5 — Super ! *2016-04-01* J'avoue que c'est quand même un super gadget qui permet d'émuler cet instrument de musique très étrange. On retrouve effectivement les sonorités mais il manque quand même un contrôle car le terremin d'origine utilise deux antennes. Mais c'est quand même bien fun de créer des sons sans toucher le téléphone ### 4/5 — Sounds good but... *2013-11-19* The sound is pretty authentic, but a real theremin isn't zippered. ### 4/5 — Very nice app!!! *2013-11-06, version 1.0* This app is a real theremin! Never seen anything like it before. You can play music just by moving your hand in front of the iPhone camera and there's plenty of preset tones to play with. Very fine design too, looks like a little robot :) Great job! ### 5/5 — AWSOME!!! *2016-10-19* This tool for making sound is truly fantastic! I have used it in the recording studio and even used it on stage! You just need to download it, experiment and fun! That's all I can say! If your looking for a really cool, responsive and versatile instrument on your phone...look no further! Enjoy!!! ### 5/5 — Awesome simulation! *2015-10-31* The GUI is top notch. Way above other apps that try to mimic the theremin. Very customizable and well worth the small cost. ### 5/5 — Fun Fun Fun *2014-04-28* Too cool try it ! ### 5/5 — Bellissima *2014-02-23, version 1.0* Un vero theremin ## Most praised reviews (3 highest-rated) ### 5/5 — Cool gestures *2014-01-31* It's a fun little app to experiment with camera gestures like air vox ### 5/5 — Very, very cool. *2013-12-09* Not only is it sensitive to your hand motions, but it calibrates well for light conditions. Also, lots of voices and harmonic settings. Very nicely done. ### 5/5 — Incredibly cool *2013-11-08* Functions perfectly! The light sensor functionality is virtually flawless and the sound presets sound beautiful! It's really cool controlling the sound just by moving your hand closer or further away from the iPhone. You can also manually adjust vibrato and delay for added customization. In addition, they give you around 70 unique scales to choose from, and an option to just use the whole keyboard! It's one of my favorite apps! --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-17.*