MIDI Aid vs Contour
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
MIDI Aid
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MIDI Aid is a MIDI monitor: connect your MIDI devices and see every incoming event in one clean, technical view. Whether you are debugging a synth patch, checking a controller mapping, or just curious what your gear is sending, MIDI Aid shows you what is really happening on the wire. CAPTURE • Live event log with precise timestamps • Start, pause, and resume capturing at any time • Clear the log with one tap • Follow mode keeps the newest events in view UNDERSTAND • Every event decoded into plain language: notes with names and velocities, controllers with their standard names, program changes, aftertouch, pitch wheel, and more • Raw status and data bytes side by side with the decoded event • Hex or decimal display, your choice • Tap any event for a detail view including the full raw bytes FILTER • Focus on what matters: filter by device, event type, and MIDI channel • Channel events, system common events, and system real time events can be toggled individually • Mute noisy events like Timing Clock or Active Sensing with one tap DEVICES • Works with USB MIDI devices out of the box • Network MIDI sessions and Bluetooth MIDI devices set up at system level appear automatically MIDI Aid supports all 16 MIDI channels, running status, and System Exclusive messages. No account, no ads, no tracking. Your MIDI data never leaves your device. MIDI Aid only counts anonymously which features are used; a random install ID is added only if you allow it.
Contour
This app is a unique musical instrument played by touch. It uses a visual interface where your finger's position determines the sound, offering a novel way to create drones, textures, and pads. It also functions as an AUv3 plugin for use in other music production apps.
- Touch-based sound generation
- Perceptual distance mapping
- Eleven distinct sound sheets
- MIDI input and ribbon controller
- AUv3 plugin support
- Recording functionality (Pro)
- Customizable sound sheets (Pro)
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Contour is an instrument you play by walking. Four neural decoders sit at the corners of a square. Your finger somewhere in the middle is a blend of all four, and the square is drawn as a survey sheet. The contour lines are not decoration. They come from what those four decoders actually produce, laid out so that equal distances on screen are equal perceptual distances in sound. Cross a line and the sound has changed by a measured amount. THE SHEETS Eleven of them, each a different set of four corners, each chosen by measuring the whole library rather than by ear. They are grouped by what the measurement found: BRIGHT — HEHUAN, the brightest, where all four corners hold their own. CONTRAST — BEIYIDUAN, the widest corner spread at 8.2 times. BREATH — NENGGAO, the breathiest. DEPTH — MABO, the deepest at 53 dB. RANGE — YUSHAN, the widest at 66 semitones; JIAMING, the most focused at 17. They are named after Taiwan's high mountain traverses. PLAYING IT Touch the sheet to sound it. The ribbon underneath sets pitch, or send MIDI and play it from a keyboard. Press harder and the note opens up — the contact patch of your finger is the dynamic. Hold on empty ground to drop a mark you can come back to. The readout above the ribbon tells you where you are while you are there: brightness, noise, the grid reference, the frequency. IN A HOST Contour is also an AUv3 plug-in. It runs in AUM, GarageBand, Cubasis, Logic for iPad and anything else that hosts Audio Units, with the position automatable as two parameters and the sheet recallable with your session. The plug-in draws the same map the app does, laid out for the window a host gives it. WHAT IS FREE Three sheets — BEIYIDUAN, NENGGAO and YUSHAN — with the whole instrument: the map, the ribbon, MIDI, reverb, marks, and the plug-in. No time limit and no account. CONTOUR PRO A single purchase, once, unlocks: • All eleven sheets • Recording, straight to a file • The envelope panel — attack, decay, sustain, release • Composing sheets of your own from the library, 4,845 combinations of four corners, with the map baked for the pitches they share Requires iOS 16 or later. iPhone and iPad.
Screenshots
Verdict
The clearest difference is price: Contour at Free against MIDI Aid's $0.99. Contour also leads on update cadence (weekly vs every 7 months). MIDI Aid's advantage is in-app purchases (none vs 1). On ads, device support and iOS requirement 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
Contour is free to download; MIDI Aid costs $0.99 up front. Contour sells 1 one-off in-app purchase. MIDI Aid asks for nothing beyond the download.
MIDI Aid ships an update every 7 months, Contour weekly. The most recent releases landed on October 26, 2026 and October 25, 2026 respectively.
| Parameter | MIDI Aid | Contour |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | — | 4.0 (2 ratings) — better |
| Positive reviews | — | 0.0% of reviews |
| Number of ratings | — | 2 — better |
| Update frequency | Every 7 months | Weekly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Freemium |
| Devices | iPhone, iPad, Mac — better | iPhone, iPad |
| Requires iOS | 16.0 | 16.0 |
| Further details — not scored | ||
| Size | 29 MB | 108 MB |
| Age rating | 4+ | 4+ |
| Developer | Tobias Wissmueller | Chih Han Lin |
In-app purchases
MIDI Aid
No in-app purchases
Contour
- Contour Pro$3.99









