Audio Unit Player vs Contour
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Audio Unit Player
This music player offers real-time audio processing, including time stretching, pitch shifting, and a 31-band equalizer. It supports AUv3 effects and allows for A-B loop playback, making it ideal for practice, transcription, and performance adjustments.
- Real-time time stretch (50-200%)
- Real-time pitch shift (-12 to +12 semitones)
- 31-band equalizer with presets
- AUv3 effects support
- A-B loop playback
- Background playback
- Audio file export
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This app is a music player that can process the following effects in real time. - Time stretch (0.5-2.0 double speed) - Pitch shift (-1 ~ +1 octave) - 31 band equalizer - Reverb - AUv3 (Audio Unit v3) host [Use cases] - Karaoke's training. (Can be changed speed units of 10%, pitch shift in semitones easily) - Can playback at reduced tempo to copy phrase for guitar or bass, the keyboard instrument. - Can playback by changing the pitch to play by changing the key in the band performance (Developer himself has experience). [Function] - Perform time stretch (50 - 200%) / pitch shift (-12 - +12) in real time. - 31 bands EQ (Hz: 20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1k, 1.25k, 1.6k, 2k, 2.5k, 3.15k, 4k, 5k, 6.3k, 8k, 10k, 12.5k, 16k, 20k). - EQ preset (Abundant Built-in Presets / Custom Presets). - Reverb: Adjustable decay time (Low freq, High freq) / 13 presets - Reverb preset (Built-in Presets / Custom Presets) - Can be used as an AUv3 host. - A-B loop playback. - Center Cancel / Center Emphasis. - Lch, Rch each mute. - Quick fast forward, rewind (specify the number of seconds). - Check and set current position graphically in wave view. - Supports Auto-Lock ON/OFF. - Supports background playback. - Supports export (file writing) function (Each effect (speed/pitch/EQ) value set for each song is also reflected. The range specified in the loop section is output.) In addition to loading "music" data included in the standard music app, it also supports the function to import audio files from other apps ("Voice Memos" etc.). [How to import from "Voice Memos"] 1. Start the app "Voice Memos" and tap the mark "..." of the file to be imported from the list. 2. Tap "Share" on the sheet displayed from the bottom. 3. Tap "More" found by scrolling the displayed list of sharing destination apps to the right. 4. Select "AU Player" if available. The file is copied to this app. ================================================ [Note 1] This application will not be able to read songs of the following formats. - Songs from Apple Music, iCloud, iTunes Match - Songs that are protected by digital copyright (DRM) [Note 2] Depending on the state of your device, your custom AUv3 effects may not appear in the list. As a solution, you can solve the problem by starting "GarageBand" once and restarting this app. ================================================
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
Audio Unit Player and Contour both sit at 3.9 stars, but that hides the real split: 67% of Audio Unit Player's written reviews are positive against 0% of Contour's. Audio Unit Player also leads on ratings volume (32 vs 2). Contour's advantage is ads (none vs shown) and update cadence (weekly vs every 2 weeks). On price, rating, in-app purchases and device support 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
Both are free to download. Audio Unit Player sells 1 one-off in-app purchase and Contour sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 3.9 for Audio Unit Player against 4.0 for Contour. That said, the two scores are not equally well evidenced: Audio Unit Player has 32 ratings behind it against 2, so its average is the more settled of the two. Written reviews are what separate them: 67% of Audio Unit Player's written reviews are positive against 0% of Contour's.
Audio Unit Player ships an update every 2 weeks, Contour weekly. Both last shipped on October 29, 2026.
| Parameter | Audio Unit Player | Contour |
|---|---|---|
| Price | Free | Free |
| Rating | 3.9 (32 ratings) | 4.0 (2 ratings) — better |
| Positive reviews | 66.7% of reviews — better | 0.0% of reviews |
| Number of ratings | 32 — better | 2 |
| Update frequency | Every 2 weeks | Weekly — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | Yes |
| Monetization | Paid | Freemium — better |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 | 16.0 — better |
| Further details — not scored | ||
| Size | 5 MB | 108 MB |
| Age rating | 4+ | 4+ |
| Developer | Loop-Sessions.LLC. | Chih Han Lin |
Customer experience
Audio Unit Player
Contour
In-app purchases
Audio Unit Player
- Always remove banner ads.$3.99
Contour
- Contour Pro$3.99








