CoVariant app for iPhone and iPad

CoVariant is a set of audio units that turn a DC coupled audio interface into a MIDI to CV converter. The audio units convert MIDI note and controller data and timing information from the host app to control voltages that can be used to control external analog synthesizers, modular systems, sequencers, drum machines or other CV controlled analog equipment.

The app contains five audio units that can be loaded by AU host apps. Please note that these audio units do not run stand-alone: they require a compatible host to work.

CoVariantAU is a MIDI to CV converter that provides outputs for CV/Gate, two MIDI controllers and two ADSR-type envelope generators. It supports last, low and high note priorities, multiple or single trigger modes, legato or continuous glide/portamento with constant rate or constant time modes and pitch bend. The controller outputs can be set to note velocity, aftertouch or any MIDI continuous controller number (0 to 127). Controller outputs are smoothed to prevent any stepping.

TriggerAU is a simplified version of CoVariant AU that responds to MIDI note events and provides outputs for gate/trigger and one MIDI controller. Its primary purposes are to control drum modules or to convert MIDI controller data to control voltages.

ClockAU provides outputs for Clock and Run/Stop/Reset, allowing analog sequencers and DIN Sync drum machines or synthesizers/sequencers to be synchronised to the tempo and transport of the host app.

PolyphonyAU is a MIDI processor that functions as a polyphonic voice controller for multiple instances of CoVariantAU.

EncoderAU allows the use of the Expert Sleepers ES-5, ES-40, ESX-8GT and ESX-8CV eurorack modules. The outputs from the other AUs (or any other software capable of acting as a CV/Gate souce) may be routed to the hardware outputs of the ES / ESX modules.

The Audio Units require a host application that supports multi-channel audio interfaces. Please note that GarageBand lacks this ability and so is not suitable. The accuracy of the ClockAU is dependent on the timing and transport state data provided by the host app. EncoderAU requires a host app that can support an AU with multiple input busses (AUM by Kymatica fully supports this AU).