When dealing with small packages you often need to look at the code, because the documentation is sometimes lacking.
AudioIO.jl uses the C library PortAudio, so in theory anything that can be done with PortAudio can be done in Julia, you need to have the right wrappers for the C functions. It seems AudioIO.jl implementation isn't complete, so probably some things cannot be done currently without getting your hands dirty (meaning reading the Julia code and the PortAudio doc and trying to understand what's going on). if you look the constructor of PortAudioStream you can see you can change the sampling rate there (the PortAudioStream can then be passed to play it seems), however it call the default stream (Pa_OpenDefaultStream) so I'm not sure you can select the audio device. There's also a get_portaudio_devices function, but it's not used anywhere it seems (you can search the repository to see where things are used) https://github.com/ssfrr/AudioIO.jl/blob/26fd1fdf232fbe8a0115203f8c253c8cff7a0827/src/portaudio.jl#L53 I don't know much about PortAudio, so take that with a grain of salt, I'm just guessing.
