StepPolyArp MIDI Arpeggiator Updated With Polyrhythm Support & More

Developer Laurent Colson has released a major update to StepPolyArp, his advanced iOS MIDI arpeggiator.

StepPolyArp can be used to control Midi instruments, sequencers like Logic, Cubase, Live, other MIDI sequencers, or even other virtual instruments installed on the same iPad. The arpeggiator can automatically generate melodic patterns from notes or chords played in real time.

Here’s what’s new in StepPolyArp v3:

  • Polyrhythm lines
  • iOS 11 support
    Resizable Keyboard
  • Keyboard is scrollable from the bottom area
  • Presets available from “Files” application
  • Full support of “Split View” and “Slide Over”
  • Graphics and user interface improvements
  • Option to retrig the position of a pattern when launching
  • The scale can be saved with pattern
  • Open presets created from version 1.x and 2.x
  • Added a drum kit in the internal sounds
  • Added new presets


  • 1 to 32 steps programmable matrix
  • 16 patterns by preset
  • Polyrhythm lines
  • Automatic chaining patterns
  • 11 configurable transposition lines
  • Features copy and paste
  • 8 octaves resizable keyboard
  • Multitasking
  • Internal sound bank
  • Tap tempo
  • Receiving Midi notes and control from external devices
  • External Midi sync (Midi Clock)
  • Midi over wifi latency compensation
  • Internal routing of inputs, outputs and Midi sync
  • Send Midi to a virtual port that can be used as Midi input by other Core Midi compatible
  • applications managing multitasking on the same device
  • Velocity, modulation, pan, volume, aftertouch and pitch bend step controller
  • Customizable step controller Midi datas
  • The arpeggiator and keyboard fit the selected scale
  • 6 arpeggiator modes
  • 1 random mode
  • 1 chord mode
  • Unlimited number of saves
  • Random patterns creation
  • Presets manager
  • iCloud and iCloud Drive support
  • Presets shared between computer and iPad using iTunes 9.1 or later
  • Presets available from “Files” application
  • Full support of “Split View” and “Slide Over”
  • 128 Undo/Redo levels
  • Lockable keyboard (latch mode)

Pricing and Availability

StepPolyArp is available for iPad for US $14.99.

8 thoughts on “StepPolyArp MIDI Arpeggiator Updated With Polyrhythm Support & More

    1. Yup… you’d think by now, for the price class, this thing would either go the AU route to allow multiple instances, or be able to have multiple arps…

      Speaking of arps, the arp settings in the new KASPAR synth are really cool. So much amazing for $4.00!!!

  1. @ Salt each note row can be assigned to a different channel in settings on left .

    Another misuse of the term “polyrhythm” ( like Beatstep Pro/Drumbrute misuse ) ,
    as it seems to be polymeter in fact .
    Each row runs along its number of steps indepenently at the same tempo ,
    thus each completes its cycle at a different time = polymeter .

    a true polyrhythm would complete whatever differing number of steps over the SAME time , by varying the tempo of each row , so they all restart each bar together .

    1. But they all share modulation and velocity?

      This would be my dream sequencer, if it had 4 simultaneous instances.

      ? perhaps I could buy 3 more iPads…

  2. I agree. Another way to say it is that with polyrhythms, you can have different step rates per beat(s). And these apps which claim to have “polyrhythmic” abilities offer only the ability to vary the length of each track in 16th note increments but the result is still walt-to-wall 16ths.

    Yes, you can jump through hoops to make other kinds of things happen, but if it isn’t baked into the workflow, then it’s just tedious and limited.

  3. Sparkle and stub

    Not sure why you’re getting hung up on their take on polyrhythm -it’s a catch-all term to begin with, not a specific technique.

    About the ‘non-stop’ 16th notes – traditional polyrhythms are based on a common pulse, and for step sequencing, it doesn’t matter if you call them 8ths, 16ths or whatever – understanding the polyrhythm means understanding the pulse and being able to play against it in different meters or rhythmic groupings.

    The Buchla sequencer does avant-garde polyrhythms, but it also costs more than most synthesizers.

    If you just want to play 7 notes against 11, there are cheap iPad apps that let you do that, like Concentric.

    1. It’s a pretty common MIS-usage. Some developers claim to offer “polyrhythmic” capability by simply allowing users to adjust the length if a track in step increments. This provides control of group or cycle length, but doesn’t offer control of step-rate.

      Some apps like Molten, Patterning, DrumPerfect, and all the LumBeat drum machines– will let you change the step rate on a track, or on each beat individually. And those apps are welcome to boast that they offer polyrhythmic capability.

      If I want a polyrhythm of 5 over 4, I do have a common pulse, but if I am placing the 5 over 4 beats, I need each beat to be divided into quintuplets. Yes, I can make a 20 step sequence and ignore the BPM– and not sync to the outside world.

      If an app is polyrhythmic it should be smarter than me, not a lot dumber.

  4. Agreed on the misuse of ‘polyrhythm’. @jert, one simple way to think of it: with polyrhythms, measure downbeats (often) remain the same. So 12345 over 1234 will have ‘the one’ in sync each time. That means one is playing, er, 5th notes while the other is playing quarter notes.

    Another way to think about it… ‘the pulse’ is actually different in polyrhythmic music. The tempo, however, is the same though. So even divisions of the BPM are actually different *rhythms*.

    iOS sidebar: Quantum can do both polymeters and polyrhythms. At the same time.

    Anyway, SPA is boss. And worth the price to me, especially with polymetric support. It’s a total blast. I don’t think it’s mentioned in the press release but the control patterns (velocity, etc) can also have their own length.

    I’d love to see it go full-multitrack or AU MIDI but as is, it’s totally worth 15 bucks. It’s absurdly good at what it does. To me, presuming I want what it does, that’s worth a movie ticket.

    Fun times: set three lanes to three different length patterns. Set the all to 0 (no transpose). Set them to 1, 2 and 3 respectively in the note settings so that each lane will only play the 1st, 2nd or 3rd note in the chord. Set the ARP direction to chord mode (three lines I think) Play a chord and instead of getting regular arp, you get each note in the chord at different rhythmic pulses. With different loop lengths, it can evolve over time.

    Extra fun, point each row at a different synth.

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