Numerical Audio MIDIRackMIDIRack is a MIDI toolkit for iPad: a control surface builder combined with an optional visual MIDI processing graph. Users build a custom touch surface from keyboards, step sequencers, knobs, faders, XY pads and buttons on a snapping grid, and send MIDI to any synth, app or hardware. It runs standalone or as an AUv3 MIDI processor in hosts such as AUM, Logic Pro, GarageBand, Cubasis, Drambo and Loopy Pro. MIDIRack is the successor to the KB-1 Expressive Keyboard Suite. Performance surface (base app) Six keyboards from KB-1, each a routable node with latch and octave shift: velocity-sensitive piano, diatonic chord pads, scale-locked keyboard, MPE Seaboard-style ribbon (per-note glide and slide), MPE Strings grid in 4ths, and a 4×4 GM drum-pad grid. A suite of tap-to-edit sequencers: drum, melody, chord, analog and CC step lanes plus a Matrix note grid — per-step velocity, probability, tie, trigger conditions and microtiming; 4 pattern banks per lane with chaining; a 4-pad scene launcher that switches every lane's pattern at once. Analog Seq: a knob-per-step sequencer with slide steps and a built-in key/scale quantizer that re-roots live from played notes. Knobs, faders, XY pads, buttons and live visualizers, bindable to raw MIDI CC or graph parameters. Built-in polyphonic synth (MPE-aware) and drum kit, so the app plays out of the box. CoreMIDI in/out plus an always-on virtual port ("MIDIRack Out"); connects to desktop DAWs over USB (IDAM) or Bluetooth MIDI with no driver or helper app. Output on all 16 MIDI channels plus a dedicated MPE connector. Graph Editor (in-app unlock) A visual canvas wiring MIDI In processors MIDI Out, with 60+ node kinds: arpeggiator, scale/key quantizer, transpose, chord, echo, ratchet, humanize, swing, euclidean rhythms, LFO, envelope, sample & hold, CC tools, and more. Generative "emergence" nodes: Conway's Game of Life, Turing machine, Wolfram rules, Markov chains, bouncing balls and a Lorenz attractor. Instrument nodes: Synth, Drums, Sampler and a loop Slicer (auto-slices a loop into 16 one-shots with a sequencer lane per slice). Every surface keyboard is its own node in the graph; surface controls bind to graph parameters and move on screen as LFOs modulate them. Factory patches by category (control surfaces, generators, keyboards, utilities), including self-playing patches such as the Amen Engine breakbeat machine. Without the unlock, factory graph patches can be opened and run; editing and saving require the purchase. Pricing One-time purchases, no subscription: base app $14.99, Graph Editor unlock $14.99. Introductory pricing of $7.99 each through August 31, 2026. Requires an iPad on iPadOS 18 or later. iPhone and Mac (Apple silicon) versions are in development. Read More