Comparison

Synesthesia Synth vs ThereminAir

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

Head to head
About

Synesthesia Synth

An experimental audio-visual instrument that allows users to sculpt evolving spatial audio by manipulating floating capsules. Position, rotation, and pulse changes affect tone, texture, and synchronized particle generation. It's a visual synthesizer, not a game.

Highlights
  • Experimental audio-visual instrument
  • Sculpt evolving spatial audio
  • Manipulate floating capsules
  • Control tone, texture, and particles
  • Visual synthesizer
Read full description

Synthaestesia is a free experimental audio-visual instrument. Three capsules float in space. Every contraction produces sound. Move them, rotate them, reshape their pulse — and sculpt evolving spatial audio. Position changes tone. Rotation alters texture. Delay generates synchronized particles. This is not a game. It’s a spatial synth you can see.

About

ThereminAir

This app transforms your Apple Watch into a unique theremin instrument. Play music through arm gestures, controlling pitch and volume without touching any buttons. Explore different modes and scales to create a variety of sounds.

Highlights
  • Gesture-based pitch and volume control
  • Pure mode for continuous glide
  • Scale modes for staying in tune
  • Adjustable pitch ranges and vibrato depths
  • Live readout of frequency and note name
  • Complication for instant play
Features
Read full description

ThereminAir turns your Apple Watch into a theremin — the legendary instrument you play without ever touching it. Anchor your elbow and sweep your forearm like the hand of a clock: raise it and the pitch rises, lower it and the pitch falls. Rotate your wrist to swell the volume. There are no buttons to press while you play, no strings, no keys — just the motion of your arm in the air, exactly like the real thing. Your arm becomes the antenna. HOW IT WORKS • Sweep your forearm for pitch — glide smoothly or lock to musical notes • Rotate your wrist for volume — from a whisper to full voice • Wobble your wrist on a held note and it sings with real vibrato • Turn the Digital Crown to set your maximum volume • Watch the live readout — frequency, note name, and a scrolling trace of your vibrato PLAY IN KEY Pure mode gives you the classic continuous theremin glide. Prefer to stay in tune? Choose a scale and every note snaps to it: • Major and Minor • Major and Minor Pentatonic • Pick any root note Vibrato sings around the note you land on, so playing in key never sounds locked to a grid. MAKE IT YOURS • Three pitch ranges — Precise for playing in tune, Standard for everyday play, Wide for drama • Three vibrato depths — Subtle, Natural, Wide • The tone brightens as you play louder, the way an acoustic instrument does • Plays the right way round on either wrist, in either crown orientation • Vibrato-only mode, so travelling to a new note stays clean RECOMMENDED SETTINGS Precise range · Pure scale · Dynamic timbre on · Wide vibrato depth · Vibrato only on · Travel-proof vibrato off · Exclusive audio off TAP AND PLAY Add the ThereminAir complication to your watch face and a single tap launches you straight into play mode — no menus, no waiting. Or just say "Hey Siri, play ThereminAir". BUILT FOR THE WATCH • Smooth, low-latency synthesis tuned for Apple Watch • Clean, glanceable interface • Works on the go — your instrument is always on your wrist Whether you're making eerie sci-fi sweeps, practicing pitch, or just playing with sound while you wait for coffee, ThereminAir puts a real instrument on your wrist.

Screenshots

Synesthesia Synth2 screens

Verdict

The call

The clearest difference is price: Synesthesia Synth at Free against ThereminAir's $3.99. On rating, ratings volume, update cadence and ads 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

CostPrice · In-app purchases · Ads · Monetization

Synesthesia Synth is free to download; ThereminAir costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for Synesthesia Synth against 5.0 for ThereminAir. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

UpkeepUpdate frequency

Synesthesia Synth ships an update every 10 days, ThereminAir every 11 days. The most recent releases landed on October 19, 2026 and October 11, 2026 respectively.

Scorecard1 real difference · 8 level
Synesthesia Synth versus ThereminAir: the parameters behind the verdict, then further details
ParameterSynesthesia SynthThereminAir
PriceFree — better$3.99
Rating5.0 (2 ratings)5.0 (1 ratings)
Number of ratings2 — better1
Update frequencyEvery 10 days — betterEvery 11 days
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPadiPhone, iPad, Apple Watch — better
Requires iOS16.0 — better17.0
Further details — not scored
Size141 MB2 MB
Age rating4+4+
DeveloperMICHELE ZACCAGNINITom Pardee

In-app purchases

None

Synesthesia Synth

No in-app purchases

None

ThereminAir

No in-app purchases

Questions

Is Synesthesia Synth free?
Synesthesia Synth is free to download, with no in-app purchases.
Is ThereminAir free?
ThereminAir costs $3.99, with no in-app purchases.
Which has better reviews, Synesthesia Synth or ThereminAir?
Synesthesia Synth and ThereminAir are both rated 5.0 out of 5 on the App Store, from 2 and 1 ratings respectively.
Do Synesthesia Synth or ThereminAir have ads?
Neither Synesthesia Synth nor ThereminAir shows ads.
Which is updated more often, Synesthesia Synth or ThereminAir?
Synesthesia Synth ships an update every 10 days, and ThereminAir every 11 days. Most recently, Synesthesia Synth was updated on October 19, 2026 and ThereminAir on October 11, 2026.

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