
#Mac sound settings set a default microphone windows
Microsoft does not restrict Windows to a select group of systems (the way macOS only works on an Apple device, with the exception of unsupported Hackintosh builds). Unlike in the Windows world, where a Default Device can be set in the Sound Settings, Macs (unlike PC's) have a built-in speaker and microphone in pretty much every single (recent) computer ever released. This is how Apple views it and most customers don't want to put up with picking the right source every time they connect a pair of headphones. Input switching occurs when the new input/output device has microphone capabilities, which (in theory) gets the mic closer to the user thus produces greater audio and reducing background noise through less distance between the source and the mic - as the majority of headphones/earphones do with a built-in mic. I may not be the answer you are looking for but I wanted to share this information with you anyway, in the hope that it shows the problem from a different perspective or somebody is able to add to my thinking. I have added a simple trick (that you may already be aware of) to switch between input devices quickly and given an explanation as to why macOS behaves this way. Right now, to the best of my knowledge, it is not possible to prevent the input/output switching between external devices and the onboard instruments using built-in features from the Operating System.
