I am using two AudioDeviceManager instances, one for input and one for output (I know one AudioDeviceManager can handle input *and* output but only when the sample rate is the same).
I have an Apple monitor with built-in audio. The first AudioDeviceManager to select the "Display Audio" device works fine, but when the other one selects it, it's audioDeviceAboutToStart() callback is called but audioDeviceIOCallback() is not.
What could be wrong? Where can I look for problems?