StepPolyArp is a versatile and powerful application that functions as a real-time polyphonic and polyrhythmic MIDI step arpeggiator and step sequencer. Developed by Laurent Colson, this program is available for iPhone and can be used as a standalone application or an AUv3 MIDI effect plug-in.

In arpeggiator mode, StepPolyArp automatically generates melodic patterns from played notes or chords. It features a 1 to 32 steps programmable matrix with 11 configurable transposition lines, allowing for complex and unique arpeggiations. The polyrhythmic lines add a dynamic and rhythmic element to the arpeggiator engine.

StepPolyArp also functions as a step sequencer, eliminating the need for MIDI input to play. It supports 16 patterns per preset, with the ability to chain patterns automatically. The application includes an 8-octave resizable keyboard for easy input.

With full internal and external MIDI connections, StepPolyArp offers seamless integration with other MIDI devices and software. It supports Ableton Link sync and MIDI clock source sync, ensuring precise timing and synchronization. The program also includes an internal sound bank for immediate sound exploration.

Whether used as a standalone application or an AUv3 MIDI effect plug-in, StepPolyArp offers a wide range of features for musicians and producers. Its customizable steps controller MIDI setup, arpeggiator modes, random patterns creation, and chord mode provide endless possibilities for creating unique and innovative compositions.

StepPolyArp supports multiple instances as an AUv3 MIDI effect plug-in, and is compatible with hosts such as Logic Pro, Cubasis, Beatmaker, AUM, Audiobus, NanoStudio, Auria Pro, and apeMatrix.

With its comprehensive feature set and intuitive interface, StepPolyArp is a valuable tool for musicians looking to add depth and complexity to their compositions.