Konstrukt 1.2, formerly MIDIRack, adds AUv3 hosting and recording
Numerical has released Konstrukt 1.2, the music app for iPad and iPhone that used to be called MIDIRack, for $7.99 on the Apple App Store. The update adds AUv3 plugin hosting, built-in synthesizers and effects, audio recording and a mixer to what began as a MIDI tool.
Sequencers for drums, chords and stages
Drum Grid fits the rows of a whole drum kit onto a single card for programming percussion. The Stage Sequencer works in eight stages. Each has its own pitch and pulse count, and the sequencer adds gate modes, ratchets, slide and skip. The Chord Sequencer picks up Rhythm, Strum and Voicing layers.
Pattern generators can seed lanes in the Drum, Drum Grid, Step, Analog and Chord sequencers. You pick a style, set a Complexity value and get a starting pattern. It stays editable with the ordinary sequencer controls.
Fragments and a wider graph editor
The visual graph editor from the first MIDIRack release stays, and it now routes audio as well as MIDI. The node library has over 80 types: MIDI processors, generators, instruments and effects. It also draws the routing set up on the Rack page: instrument outputs, effects, sends and sidechain links.
Fragments let you select connected nodes and store them as one reusable component. The group collapses into a card with its own inputs and outputs. Control assignments made on the nodes carry over into the saved fragment, and the card can be placed in other patches, where it remains editable.
Plugins and built-in sound
Konstrukt can host third-party AUv3 instruments, effects and MIDI effects inside the standalone app. Plugins open in floating windows and keep their own presets. Their parameters can be mapped to controls on the custom performance surfaces.
No plugins are needed to make noise. The built-in instruments are an Analog synth with two oscillators, a Wavetable synth, MegaSaw, a drum instrument, a sampler and a loop slicer, with 164 factory sounds sorted into categories. Eight effects come with them: Drive, Filter, Delay, Reverb, Compressor, EQ, Chorus and Phaser. Each has a hardware-style control panel.
Mixing, recording and sync
On the new Rack page, mixing happens per instrument: level, pan, mute and solo sit beside insert effects and auxiliary sends. Sends can be pre- or post-fader and go to bus channels, and sidechain routing is supported. The master channel has insert effects of its own, scenes recall mixer levels with adjustable fades, and MIDI Learn lets hardware controllers move faders and pans. An External Instrument channel links a hardware synth's MIDI output to the audio routing.
Audio input channels bring in external instruments, microphones and other sources. From the transport you can record the master output, or only the channels you have armed, as 24-bit WAV files. Sync covers Ableton Link, MIDI clock in and out, tap tempo and a metronome with count-in. Multi-output routing works with compatible multichannel audio interfaces.
What carried over from MIDIRack
MIDIRack first appeared in August 2026 as an app for building MIDI instruments. Users made custom performance surfaces from touch keyboards, pads, knobs, faders and sequencers. Six keyboards came over from the KB-1 Expressive Keyboard Suite: piano, chord pads, a scale keyboard, two MPE controllers and drum pads. Konstrukt also offers CoreMIDI and virtual MIDI connections, MPE included, and can run as an AUv3 MIDI processor or instrument in compatible hosts.
Source: Synthtopia