Comparison

Syntheremin vs Index Theremin

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Syntheremin

Read full description

Play the air. Syntheremin Instrument turns the space in front of your iPhone into a continuous musical instrument. Move both hands through the camera view to perform without touching the screen. PLAY CONTINUOUS PITCH Move your dominant hand horizontally through the note field. Raise or lower it to keep gliding smoothly across octaves—without the steps of a keyboard. CONDUCT THE VOLUME Raise your other hand to swell and lower it to quiet. Keep it still for a steady level, or close your fist for an immediate mute. SCULPT THE SOUND Roll your pitch wrist to sweep an analog-style filter. Roll your volume wrist to move from dry and focused to wide with a short echo. BUILD HARMONIC THREADS Touch matching fingertips to layer an octave, scale third, scale fifth, or high shimmer. Stretch the glowing connections to intensify them, then pinch a connected finger to release its voice. MADE TO BE PLAYED • Classic, Choir, and Glass synth characters • Scale-based note gravity that helps intonation while preserving glides • Live pitch lanes, note readout, and tuner • Role-colored hand tracking that shows what the instrument hears • Right- and left-handed layouts • No account, ads, or microphone access PRIVATE CAMERA PROCESSING Camera frames and hand landmarks are processed on the iPhone and are never saved or uploaded. The bundled Google MediaPipe SDK sends limited usage and performance metrics to Google; details are available in the in-app Privacy screen and privacy policy. REQUIREMENTS Syntheremin Instrument requires an iPhone with a front TrueDepth camera—the hardware used for Face ID. For the most responsive playing experience, use the built-in speaker, wired audio, or low-latency headphones.

About

Index Theremin

Features
Read full description

Theremin is a tiny instrument you play with thin air. Hold up one finger in front of your phone: raise it for higher notes, move it sideways to play louder. That's it, you're playing. Make a fist to stop. A SOUND FOR EVERY MOOD • Theremin: the classic eerie wail • Dusk: a dark, slow, melancholic synth • Aura: an airy, voice-like pad • Glass: a soft, bell-like shimmer • 8-Bit: a video-game square wave ALWAYS IN TUNE Auto-Tune snaps you to a scale (major, minor, pentatonic or every note) in any key. Hard for the robot effect, Smooth for a gentle glide. PLAY A DUET Turn on Duet Mode and each hand becomes its own instrument, with its own sound and settings. MORE TO PLAY WITH • Reverb and Pulse effects • Volume and octave for each hand • Make a fist to mute without hiding your hand • Portrait or landscape, iPhone and iPad PRIVATE BY DESIGN Hand tracking happens entirely on your device. Nothing is recorded, uploaded or collected.

Screenshots

Syntheremin4 screens
Index Theremin4 screens

Verdict

The call

Syntheremin and Index Theremin are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ScorecardNo meaningful differences
Syntheremin versus Index Theremin: the parameters behind the verdict, then further details
ParameterSynthereminIndex Theremin
PriceFreeFree
AdsNoNo
In-app purchasesNoNo
DevicesiPhoneiPhone, iPad — better
Requires iOS17.017.0
Further details — not scored
Size44 MB1 MB
Age rating4+4+
DeveloperXYK LLCNOAH REMI FINN BESENDORFER STAHLHACKE

In-app purchases

None

Syntheremin

No in-app purchases

None

Index Theremin

No in-app purchases

Questions

Is Syntheremin free?
Syntheremin is free to download, with no in-app purchases.
Is Index Theremin free?
Index Theremin is free to download, with no in-app purchases.
Do Syntheremin or Index Theremin have ads?
Neither Syntheremin nor Index Theremin shows ads.

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