CoVariant is a set of three 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.

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.

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.

What’s New

Version 1.1.0

Version 1.1.0 adds two new Audio Units:

Trigger responds to MIDI note events and provides outputs for gate/trigger and one MIDI controller. It's suitable for driving drum modules or converting MIDI controller data when the full capabilities of the CoVariant AU aren't required.

Clock generates clock and run/stop/reset signals that are synchronised to the tempo and transport state of the host app. The clock can be beat-based for analog sequencers or PPQN based for drum machines that use the DIN-Sync standard.

Ratings and Reviews

5.0 out of 5
1 Rating

1 Rating

Nsolarz ,

Must have if you use your iPad with modular synths!

Hello audio clock sync!

App Privacy

The developer, Alan Clifton, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer's privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


Alan Clifton
2 MB

Requires iOS 11.4 or later. Compatible with iPhone, iPad, and iPod touch.



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