StepPolyArp vs AU3FX
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
StepPolyArp
This app functions as a real-time polyphonic and polyrhythmic MIDI step arpeggiator and sequencer. It can generate melodic patterns from input or operate as a standalone sequencer. Save and sync unlimited presets with iCloud, featuring extensive customization for patterns and step controllers.
- Standalone app and AUv3 MIDI effect plugin
- Arpeggiator and step sequencer modes
- Programmable step matrix with transposition lines
- Polyrhythmic step controllers
- Internal sound bank
- Ableton Link and MIDI sync support
- Unlimited preset saving with iCloud sync
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"StepPolyArp" is a real-time polyphonic and polyrhythmic MIDI step arpeggiator and step sequencer. It can be used as a standalone application or as an AUv3 MIDI effect plug-in. The application and the plug-in can operate as a step arpeggiator, automatically generating melodic patterns from played notes or chords, or as a step sequencer that does not require MIDI input to play. Unlimited presets can be saved locally and synchronized with iCloud. Each preset contains 16 patterns, 5 customizable polyrhythmic step controllers, and a 32-step event matrix with 11 polyphonic and polyrhythmic lines driving the arpeggiator engine. The application supports full internal and external MIDI connections for input and output, Ableton Link synchronization, and MIDI clock synchronization. An internal sound bank is included. The AUv3 MIDI effect plug-in supports multiple instances. A compatible host is required to run the plug-in. The host must support the Audio Unit v3 (AUv3) MIDI effect format. Hosts supporting AUv3 MIDI effect on iOS: Logic Pro, Cubasis, Beatmaker, AUM, Audiobus, NanoStudio, Auria Pro, apeMatrix. Hosts supporting AUv3 MIDI effect on macOS: Logic Pro 10.7 or later. Features: • Standalone application and AUv3 MIDI effect plug-in • Arpeggiator and step sequencer mode • 1 to 32-step programmable matrix • 11 configurable transposition lines • Polyrhythmic lines and clock dividers per line • Mute by line • Gate, velocity, probability, random pitch, random gate, and random velocity per event • 16 patterns by preset • Automatic pattern chaining • 8-octave resizable keyboard • Multitasking support • Stop "Audio Background" automatically after inactivity (15 min, 30 min, 1 h, 2 h, or never) • Sample-accurate timing • Internal sound bank • Tap tempo • Receiving MIDI from external MIDI sources • Receiving external MIDI sync (MIDI clock) • Ableton Link support • Internal routing of inputs, outputs, and MIDI sync • Send MIDI to a virtual port usable as MIDI input by other "Core MIDI" compatible apps • Default velocity, modulation, pan, volume, aftertouch, and pitch bend step controllers • Customizable MIDI setup for step controllers • Arpeggiator and sequencer can conform to the selected scale • Predefined scales and possibility to create custom scales • 6 arpeggiator modes • 1 random mode • 1 chord mode • Randomization panel for generating random patterns with a large number of parameters to control the result • Preset manager with support for in-app purchase packs • "Program Change" support • Preset sharing via "AirDrop", "Mail", "Messages", and other supported services • Native iCloud support • "iCloud Drive" support in the "Files" app on iOS and "Finder" on macOS • Full support of "Windowed Apps" mode on iPad • Undo/Redo • Lockable keyboard (latch mode) Supported MIDI connections: • Virtual "Core MIDI" connections between applications • Any compatible MIDI interface • MIDI over Wi-Fi • MIDI over Bluetooth • Ableton Link (sync and transport)
AU3FX
A powerful 4-band parametric stereo equalizer AUv3 plugin for iOS. It offers detailed frequency control, real-time spectrum analysis, and customizable presets for subtle enhancements or aggressive sound shaping. Load it within compatible music apps to enhance your audio.
- 4-band parametric stereo equalizer
- High quality 32-bit DSP engine
- Interactive frequency response curve
- Real-time FFT spectrum analyzer
- Bundled presets and user preset saving
- Multiple instances and external control
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A versatile 4-band parametric stereo equalizer AUv3 plugin for everything between subtle frequency enhancements to agressive boosting/cutting or special resonator effects. This app is part of the AU3FX series, a collection of simple and powerful audio unit effect plugins. • High quality 32-bit DSP engine. • Two parametric peak filters with gain, frequency and Q. • Low-shelf filter with gain and frequency. • High-shelf filter with gain and frequency. • On/Off toggle for each band. • Interactive frequency response curve with draggable handles. • Real-time FFT spectrum analyzer with pre/post/off switch. • Comes with several bundled presets. • Use multiple instances at the same time. • Save/load session state in host. • External access and control of all parameters from host. • User presets shared across hosts (on iOS 13 and later). The container app shows the Users Guide. Load the AU3FX:PeakQ inside any music app that supports hosting Audio Unit Extensions to use the plugin.
Screenshots
Verdict
The clearest difference is price: AU3FX at $4.99 against StepPolyArp's $19.99. AU3FX also leads on in-app purchases (none vs 2) and review sentiment (100% vs 87%). StepPolyArp's advantage is rating (4.8 vs 4.6) and ratings volume (48 vs 10). On ads, monetization model 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
StepPolyArp costs $19.99 and AU3FX $4.99 up front. StepPolyArp sells 2 one-off in-app purchases. AU3FX asks for nothing beyond the download.
StepPolyArp holds the better App Store score, 4.8 against 4.6. Both are backed by a comparable volume of ratings — 48 and 10 respectively. Written reviews complicate that: 87% of StepPolyArp's written reviews are positive against 100% of AU3FX's, so the app with the better star average is not the one people write more warmly about.
| Parameter | StepPolyArp | AU3FX |
|---|---|---|
| Price | $19.99 | $4.99 — better |
| Rating | 4.8 (48 ratings) — better | 4.6 (10 ratings) |
| Positive reviews | 87.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 48 — better | 10 |
| Update frequency | Every 2 months | — |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 38 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Laurent Colson | Kymatica AB |
Customer experience
StepPolyArp
AU3FX
In-app purchases
StepPolyArp
- Dance Horizons$4.99
- Analog Sequence$4.99
AU3FX
No in-app purchases









