Ruismaker 4+‎

What the reviews say:

"A must-have drum synth for electronic music lovers on iOS" - Keyboard Mag

"All of this comes together in a vision that’s really playable [...] this is another excellent choice for the iPad." - CreateDigitalMusic

"Small, compact and easy to use, Ruismaker is both inexpensive and a perfectly credible choice if you are after solid drum synth sounds." - MusicAppBlog

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Ruismaker is a unique drumsynth plugin (i.e. it does not use samples), which is coupled with a creative Euclidean sequencer when run in standalone mode.

The plugin is fully AUv3 (Audio Unit) compatible:
- Seamless integration with Garageband and other AU hosts
- Audio Unit Instrument: making music on iOS doesn't get more convenient
- Supports Multi-Output AUv3 in AUM and ApeMatrix!
- Each sound is modeled using authentic analog and FM algorithms;
- Comes with dozens of unique customizable models
- Does not use any samples; all sounds are synthesized in realtime, on the fly
- Emulates analog components, introducing subtle, natural fluctuations in the sound
- Light on the CPU, so you can run lots of Ruismakers simultaneously
- Fully automatable parameters (requires host support) and MIDI CC controllable
- Has its own preset manager

The standalone sequencer is refreshingly different:
- Program patterns using Euclidean algorithms
- Powerful random feature and mutation probability settings per channel
- Syncs with Ableton Link or MIDI Clock
- Exports WAV and MIDI
- Compatible with Audiobus 3 (including MIDI IN/OUT mode)
- CoreMIDI In and Out
- AU MIDI output for the on-screen pads

User manual available on Ruismaker.com