Comparison

StepPolyArp vs OCTACHRON MIDI Drum Sequencer

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

Head to head
About

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.

Highlights
  • 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
Features
Read full description

"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)

About

OCTACHRON MIDI Drum Sequencer

This app is a flexible MIDI drum sequencer for iOS, offering up to 16 tracks with advanced modulation and sequencing. It can be used standalone or as an AUv3 plugin in DAWs, and is optimized for drums but also suitable for melodies. It requires iOS 12 or higher.

Highlights
  • 16 mutable tracks
  • AUv3 MIDI plugin
  • Standalone operation
  • Parameter locking
  • Smart randomizer
  • Chainable patterns
  • Custom time signatures
Features
Read full description

OCTACHRON is a very flexible iOS MIDI Drum Sequencer with up to 16 tracks and rich modulation and sequencing capabilities. It is optimized for drums, but also a lot of fun for basic melody lines. It works standalone or as AUv3 MIDI plugin in your favorite iOS DAW or mixer. (E.g. AUM, Logic Pro, Cubasis, Beatmaker, ApeMatrix, Groove Rider, Nanostudio and more (not GarageBand)) PRESS REVIEWS - “OCTACHRON is almost perfect now” (haQ attaQ) - “Favorite MIDI Sequencer - User's Choice Award 2022” (iOS AUv3 Facebook Group) - “An exciting MIDI sequencer with advanced features” (Synth Anatomy) - “Particularly the probability parameters are a lot of fun” (Amazona) !!! PLEASE NOTICE: OCTACHRON IS A MIDI SEQUENCER AND DOES NOT CREATE ANY SOUNDS OF ITS OWN !!! We believe in specialization. This is why OCTACHRON is focused on in depth MIDI sequencing. Control your favorite iOS drums like Blip Box, Ruismaker or MV08, synths like Zeeon or Model D or any other hard- or software MIDI instrument with it. iOS 12 or higher required. If used with a host software, this has to be compatible with the MIDI AudioUnit standard. OVERVIEW - Standalone or AUv3 AudioUnit - 1-32 steps with flexible clock divider and custom time signatures - Up to 16 mutable tracks with adjustable length - Up to 8 chainable patterns (song mode) - Swing with flexible swing grid - Save, restore and export your pattern presets, MIDI files and MIDI mapping presets - Parameter lock for velocity, ratcheting, offset, trigger probability, trigger condition, gate length and MIDI CC Modulation - Scales generator - MIDI control pattern selection, play and mute - Customizable mapping and mapping presets - Works iOS 12 upwards - Optimized for iPad and iPhone - Also compatible standalone with M Macs and Apple Vision Pro LOTS OF MAPPING PRESETS FOR POPULAR DRUM APPS AND HARDWARE - AR-909, Axxon 2 & Blip Box - Dadamachines Automat, Digistix & DM1/DM2/Drumlab - DrumComputer by Sugar Bytes - EGDR 606, 808 & 909 - FAC Drumkit, Hammerhead - Koala Sampler & Korg Gadgets - MV08 & NS2 Slate - Pure Acid Drums - Ruismaker & Ruismaker FM - SDS-X, Sitala & Splat-To-Clat - VA Drum SM, VA Drum2 808 & 909 - Vatanator - Korg Electribe EMX & ER-1 - Korg Volca Beats - MFB 522 - Roland MC-101 - Roland TR-08 - Roland TR-707 & 727 - Roland TR-808 - Roland TR-909 Also save, load and share your own MIDI mappings ... SMART RANDOMIZER - Smart pattern randomizer - Randomizer configuration per track - Trigger mutation per track - Mutation of internal and CC modulation parameters PARAMETER LOCK - Velocity and MIDI CC modulation - Multiple hits per step with ratcheting - Offset - Trigger probability - Trigger condition - Gate length - MIDI CC on every step - 8 CCs per Track - Mutation of Internal and CC Modulation TRACK SETTINGS - Assign MIDI notes to each track or use mapping presets - Individual track length to create polyrhythms LIVE PERFORMANCE FEATURES - Instant pattern switch option - Mute function per track to easily build up layers CONNECTIVIY - Sequence other standalone apps, AUv3 AudioUnits or external hardware via MIDI - OCTACHRON derives its timing from the host application, its internal clock or via AbletonLink - Trigger on different MIDI channels per track NO TRACKING - OCTACHRON works offline - No push notifications - No ads or in-app purchases - No tracking tools - Active on social media and in the mobile music community - Ongoing development and support and many new features on the list FOR MELODIC INSTRUMENTS GENERATE VARIOUS SCALES IN ALL KEYS OCTACHRON is optimized for drums. But it also supports standard melodic scales like major, minor and also more unusual ones like mixolydian, phrygian and more ...

Screenshots

StepPolyArp3 screens
OCTACHRON MIDI Drum Sequencer4 screens

Verdict

The call

The clearest difference is price: OCTACHRON MIDI Drum Sequencer at $9.99 against StepPolyArp's $19.99. OCTACHRON MIDI Drum Sequencer also leads on in-app purchases (none vs 2) and iOS requirement (12.0 vs 15.0). StepPolyArp's advantage is rating (4.8 vs 4.5). On review sentiment, 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

StepPolyArp costs $19.99 and OCTACHRON MIDI Drum Sequencer $9.99 up front. StepPolyArp sells 2 one-off in-app purchases. OCTACHRON MIDI Drum Sequencer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

StepPolyArp holds the better App Store score, 4.8 against 4.5. Both are backed by a comparable volume of ratings — 48 and 104 respectively. Written reviews point the same way: 87% of StepPolyArp's written reviews are positive against 81% of OCTACHRON MIDI Drum Sequencer's.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on September 22, 2026 and September 18, 2026 respectively.

Scorecard4 real differences · 6 level
StepPolyArp versus OCTACHRON MIDI Drum Sequencer: the parameters behind the verdict, then further details
ParameterStepPolyArpOCTACHRON MIDI Drum Sequencer
Price$19.99$9.99 — better
Rating4.8 (48 ratings) — better4.5 (104 ratings)
Positive reviews86.7% of reviews — better80.8% of reviews
Number of ratings48104 — better
Update frequencyEvery 2 monthsEvery 2 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidPaid
DevicesiPhone, iPad, iPod, Mac — betteriPhone, iPad, iPod
Requires iOS15.012.0 — better
Further details — not scored
Size38 MB12 MB
Age rating4+4+
DeveloperLaurent ColsonMarkus Teufel

Customer experience

StepPolyArp

All ratings48 ratings
Positive97.9%
Neutral0.0%
Negative2.1%
Written reviews45 reviews
Positive86.7%
Neutral6.7%
Negative6.7%

OCTACHRON MIDI Drum Sequencer

All ratings104 ratings
Positive88.5%
Neutral3.8%
Negative7.7%
Written reviews104 reviews
Positive80.8%
Neutral8.7%
Negative10.6%

Bugs and requests

StepPolyArp

Not enough reviews yet to summarise bugs or requests.

OCTACHRON MIDI Drum Sequencer

Reported bugs

24 issues
  • Clock div issues reported
  • No sound output reported
  • Projects broken by update
  • Skipping first note on pattern change
  • GUI glitchy/choppy
Show 19 more
  • Crashing when loading custom mapping
  • Repeating notes unexpectedly
  • Kick muting in song mode
  • Controller faders not working perfectly
  • Unwanted random notes
  • MIDI recording not an option
  • Pattern change via MIDI difficult
  • GarageBand AUv3 compatibility issues
  • No sound output
  • Projects corrupted after update
  • Clock division not working
  • Difficulty changing patterns
  • MIDI note sequences cannot be recorded
  • Choppy visual experience
  • Random notes played with ThumbJam
  • Crash when loading saved custom mapping
  • Skipping first note when switching patterns
  • Repeating notes without repeat enabled
  • Kick drum mutes in song mode

Requested features

26 requests
  • Add touchable pads
  • Add MIDI Step record feature
  • Add triplets
  • Add MIDI file export and import
  • Add system-wide preset save and load
Show 21 more
  • Add randomization for different genres
  • Increase channel count to 16
  • Add more options for MIDI input for real-time control
  • Add MIDI learn button for each track
  • Add option to record drums live into the sequencer
  • Add more patterns
  • Follow mode for song mode GUI
  • Enhanced mod edit mode with inline editing
  • Ability to drag/select patterns in song mode to auto loop
  • App preset for Arturia iSpark
  • MIDI channel per drum sound
  • Number indicating parameter value while changing
  • Ability to tie patterns
  • Note length option
  • 16 channel support
  • MIDI channel per track
  • Pattern resync for DAW synchronization
  • Expandable number of patterns and rows
  • Preview sounds
  • Import sound directly into slots
  • Triplets division

In-app purchases

2 purchases

StepPolyArp

One-time2
  • Dance Horizons$4.99
  • Analog Sequence$4.99
None

OCTACHRON MIDI Drum Sequencer

No in-app purchases

Questions

Is StepPolyArp free?
StepPolyArp costs $19.99, and also offers in-app purchases.
Is OCTACHRON MIDI Drum Sequencer free?
OCTACHRON MIDI Drum Sequencer costs $9.99, with no in-app purchases.
Which has better reviews, StepPolyArp or OCTACHRON MIDI Drum Sequencer?
StepPolyArp is rated higher. StepPolyArp averages 4.8 out of 5 from 48 ratings, while OCTACHRON MIDI Drum Sequencer averages 4.5 from 104 ratings.
Do StepPolyArp or OCTACHRON MIDI Drum Sequencer have ads?
Neither StepPolyArp nor OCTACHRON MIDI Drum Sequencer shows ads.
Which is updated more often, StepPolyArp or OCTACHRON MIDI Drum Sequencer?
StepPolyArp ships an update every 2 months, and OCTACHRON MIDI Drum Sequencer every 2 months. Most recently, StepPolyArp was updated on September 22, 2026 and OCTACHRON MIDI Drum Sequencer on September 18, 2026.

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