Sorry for the cheesy video quality… 🧀
The iOS app serves as a wireless remote control for Talkback with a suitable OSC-capable audio application ( e.g. RME TotalMix).
To adapt to your application, change the OSC Address string in setup.
If your application does not have a talkback function, you can also use any other single toggle OSC-Parameter, e.g. ‘mute on/off’