Synesthesia Synth vs IMPSY
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- Experimental audio-visual instrument
- Sculpt evolving spatial audio
- Manipulate floating capsules
- Control tone, texture, and particles
- Visual synthesizer
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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.
IMPSY
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Jam with an AI MIDI partner on iPad and iPhone. IMPSY listens to what you play and improvises musical responses. Load it as an AUv3 MIDI Processor in AUM, AudioBus, Cubasis or Logic Pro for iPad, play it from a USB or Bluetooth controller (or the on-screen faders), and route its output to any instrument app. IMPSY also runs on its own: it appears as Core MIDI virtual ports (IMPSY In / IMPSY Out) and connects directly to a plugged-in controller, so you can play it without a DAW. How it works IMPSY runs a Mixture Density Recurrent Neural Network (MDRNN) on-device. Every note, control change or pitch-bend you send becomes input to the model, which predicts what comes next, including the timing of the response. Shape the conversation with: • Threshold: how long IMPSY waits between your input and its reply • Sigma Temperature: randomness of pitch and control values • Pi Temperature: randomness of which musical "idea" the model picks • Timescale: speeds up or slows down the response • MIDI Thru: passes your own playing through to the output alongside IMPSY's Connect anything • Map each model dimension to any MIDI message (notes, CCs or pitch-bend) on any channel, independently for input and output • Connect a controller directly, or use the always-on IMPSY In / IMPSY Out virtual ports • Import and export your mappings as TOML, compatible with the IMPSY Python toolkit Custom models IMPSY ships with a default 9-dimensional model trained for general musical interaction, but you can load any .tflite model trained with the open-source IMPSY research toolkit: synths, drum machines, lighting rigs, or anything that speaks MIDI. Accessibility IMPSY is built to work with VoiceOver and Dynamic Type. Every control is labelled, the sliders are adjustable by VoiceOver, and status shows as text, not colour alone. Full statement: charlesmartin.au/impsy-auv3/accessibility.html Compatibility • AUv3 MIDI Processor, no audio I/O • Hosts in AUM, AudioBus, Cubasis and Logic Pro for iPad, or any other AUv3 host that supports midi processors. • Also runs standalone with Core MIDI virtual ports and direct device connection • Requires iOS 17 • MIDI stays on-device. No network, no telemetry
Screenshots
Verdict
Synesthesia Synth and IMPSY 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
| Parameter | Synesthesia Synth | IMPSY |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) — better | — |
| Number of ratings | 2 — better | — |
| Update frequency | Every 10 days | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad, Mac — better |
| Requires iOS | 16.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 141 MB | 18 MB |
| Age rating | 4+ | 4+ |
| Developer | MICHELE ZACCAGNINI | Charles Martin |
In-app purchases
Synesthesia Synth
No in-app purchases
IMPSY
No in-app purchases









