Audiobus: Use your music apps together.

What is Audiobus?Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.

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Audiobus is the app that makes the rest of your setup better.

Atom | Piano Roll 2 is now available

What a journey. Happy to finally say that I’ve pushed the big “Release” button and the app should start rolling out on the App Store. Now, it might not be immediately available in your country, but availability should increase throughout the day. Get it here once it does:


Atom 2 includes hardware integration for Launchpad Mini Mk3, Launchpad X and Launchpad Pro Mk3. You need iOS 14 and iCloud Drive enabled for them to work.

Pad assignment

Placing your clips onto pads and organizing them into sessions is different from what you might be used to with other plugins. Atom 2 has special integration with AUM so that your session is mirrored onto supported controllers by default.

Zoom out a bit in how you think about using the plugin: don't think of Atom as a standalone audio unit. Think of one Atom as representing a clip placed on rows and columns (tracks and slots) inside an AUM project, just like with Ableton’s "Session" view:

  • AUM MIDI channels (tracks) with Atom clips are columns on your controller.
  • AUM AU nodes (slots) with Atom clips are rows on your controller.
  • Empty channels and nodes in AUM will be empty pads on your controller.
  • AUM's node color (long press titlebar to assign one) will be closely matched to a supported color.

For other hosts, you can configure pad assignment yourself using the “Clip” menu.


No routing is necessary for the usual workflows when using supported controllers! You don’t need to constantly fumble around with the MIDI matrix to connect and disconnect the controller. If a scripted controller is connected:

  • Open a clip (make the instance visible) if you want to noodle around and experiment.
  • Arm a clip (even when the instance isn’t visible, directly from the controller) to record.

The record arm function is automatically available on the Launchpad X and Pro Mk3. Parameter mapping for opening and arming clips is available for all controllers (including non-scripted ones) in hosts that support it.

Of course, you'll still need to point your clips to the instruments you want sequenced :)

Scripting and Theming

Atom 2 can be extended with your own code. You can write scripts for hardware controllers, and new themes to change the look and feel. But beware: all of this is still very much experimental and not at all beginner friendly.

Documentation for scripting can be found here:

Notably, there’s a few things that will make this difficult right now:

  • When editing on your iPad directly, an external text editor is required. I’ve found that Textastic works great, but any other app that can add and edit files on iCloud should work just fine.
  • First-class debugging support is non-existent: there is no logging yet. You can probably hack your way around by emitting MIDI notes instead of console messages, but it’s not the perfect user experience.

Scripting is available for hardware controllers for now, and exotic integration with virtual MIDI ports and such is theoretically doable but not officially supported. Most styling use cases should be possible with themes and layout rules, but exotic things like completely changing and reshuffling the UI is not officially supported and not documented.

Upgrade bundle

As promised, I’ll request for an upgrade bundle soon. I have no timeline for when this will become available, it depends on Apple's review process which I’m told can take longer in certain situations. I don’t know exactly how bundles work, so I can’t say precisely what the upgrade cost will be, but I’m aiming for the lowest it can go.

That being said, please consider purchasing :)

Bugs reports and feature requests

If “everything that can go wrong will go wrong”, you’re bound to find a few bugs. With the plethora of possible workflows that each one of you has, you’re also bound to find some “obviously” missing features. Please reach out at, it’s the best way for me to categorize these requests. However, I’ll of course be around on the forum as well.

“Day 1” updates

Obviously there had to be a few small fixes and a couple of new features added while Apple has been busy reviewing.

The 2.0.1 update is already here. Here’s a list of changes and improvements:

  • Support for the Launchpad Pro Mk3 controller, in addition to Launchpad Mini Mk3 and X.
  • A "Sausage Fingers" mode, for people who want bigger UI elements.
  • A "Roboto" font based theme, for people who want larger and more legible text.
  • New pattern controls: "Add Default", "Add Empty", "Add duplicate", "Reset Pattern", "Delete Notes".
  • Help messages when using non-destructive processing operations.
  • Better track cloning support in AUM, cloned tracks now also show up in Layers.
  • Better iCloud support, also preventing a crash when iCloud is disabled.
  • Support for simultaneous touch and mouse input. Using both touch and mouse input together was causing instability in 2.0, update to 2.0.1 to avoid any issues!

In update 2.0.2:

  • MIDI files will now automatically set the clip length, time signature, and adjust the loop markers when imported.
  • Multi-channel MIDI files will include all lanes as separate Patterns when imported.
  • Drag and drop import from other apps. Open Files side by side, and drag MIDI files onto Atom instances.
  • New style: "Larger Fonts".
  • New Pattern controls: “Select Notes”.
  • Added basic support for the "Quantize" function on the Launchpad Pro Mk3.
  • Added support for the “Clear” and “Duplicate” functions on the Launchpad Pro Mk3 when the instance is visible.
  • Exposed AU parameters and scripting hooks for clearing/duplicating patterns, and toggling quantization.
  • Broadened the types of operations remembered on the history stack when applying non-destructive processing.
  • Improved handling of overlapping notes with applied swing for monophonic synths.
  • Improved discoverability and added helpful tips for the advanced configuration panels (available with a long-press).
  • Better performance when using many instances or importing very large clips.

In update 2.0.3:

  • Full support for Apple Pencil, and greatly improved input responsiveness overall.
  • Added a new advanced launch setting: "Choke Mode".
  • Added on-screen track choking with the Launch buttons in AUM. Turn your AUM session into a mini on-screen Launchpad.
  • Added the ability to arm record multiple clips at the same time from Launchpad X and Launchpad Pro Mk3 controllers. Enter "Record Arm" mode and tap on the pads you want to arm.
  • More layout configurations and more font themes. Combine “Larger Controls” with “Larger Fonts”, or “Sausage Fingers” with “Sausage Fonts”, or mix and match.

In update 2.0.4:

  • A user manual is now available. Find it in an instance's app menu.
  • Tapping will now preview notes on the piano roll vertical keyboard.
  • Powerful new swing controls: apply negative swing, nudge the timings or control the durations.
  • Drag and drop not just MIDI, but also scripts, styles or configurations onto your clips, and they will immediately apply to your session. Want to try out a different skin? Or bring your controller to life? Just drag and drop. Easily import and use code that others wrote!
  • Scripts now support message logging. A new directory called "Logs" is created in your Atom folder containing log files. Devices, input and output ports are automatically logged for convenience. Use console.log(...) to log a custom message from your script.
  • Controller scripts specifying an input and output port can now use either the short name or the longer label for port identification.
  • Added new ways of visualizing velocity: with colors, opacity, bar positioning or thickness, or the numerical value itself.
  • Added new ways of visualizing pitch: octave colors, highlighting in and out of scale notes and others.
  • Added a plethora of additional example styles to get you inspired.
  • Fixed an issue where certain controllers (like the Launchkey Mini) would emit high-pitched sounds when manually routed.
  • MIDI clock is now passed-through with Novation controllers when routed through clips.
  • CC messages are now passed-through (but not recorded yet) when routed through clips.
  • Mutation panel controls are now reset to default after baking non-destructive processing operations.
  • The velocity offset slider is now more accurate.


After you've used Atom 2 for a while, please consider leaving an honest review on the App Store. Cheers!



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