e.g. this command below opens the Audio tab in your Multimedia Devices applet.
RunDll32.exe shell32.dll,Control_RunDLL mmsys.cpl,,2
-lanux128
Great start ...
Once the window is open you can use ALT D to make sure the device field is highlighted.
If the device names start with different letters just press the first letter to select the device and press return to close the window.
An AHK script to do this would be:
Run, RunDll32.exe shell32.dll`,Control_RunDLL mmsys.cpl`,`,2
Sleep, 1000
send, {alt down}d{alt up}m{enter}
where m (in the last line) is the first letter of your device name.
If you make two scripts, one for each device you can just double click the correct device when you need to swap.
You may need to fiddle with the sleep delay too on your system depending on how quickly the window opens.