When setting up a microphone, if 'Use for voice output too' is not checked, the 'Voice recording device' will immediately default back to 'Built-in Audio'. It will only save the microphone settings if 'Use for voice output too' is checked.
Hello @bstascavage, Steam's voice chat has been overhauled since this issue report. If you're still experiencing this issue on an up to date system, please open a new issue report.
When setting up a microphone, if 'Use for voice output too' is not checked, the 'Voice recording device' will immediately default back to 'Built-in Audio'. It will only save the microphone settings if 'Use for voice output too' is checked.