How to permanently disconnect iPhone as sound input device to Mac?

Hello stephenbunch,

The following user guide goes over how to manage microphone access on your Mac: Control access to the microphone on Mac - Apple Support

"Some apps and websites can use the microphone on your Mac to capture or record audio. You can decide which apps are allowed to use the microphone.

1. Choose Apple menu  > System Settings, then click Privacy & Security  in the sidebar. (You may need to scroll down.)
2. Click Microphone.
3. Turn access to the microphone on or off for each app in the list.
4. If you turn off access for an app, you’re asked to turn it on again the next time that app tries to use your microphone."

Your iPhone may also be the default microphone if the switch is automatic. Check your settings here: Use your iPhone as a webcam on your Mac - Apple Support

"Make your iPhone the default microphone



1. On your Mac, choose Apple menu  > System Settings, then click Sound  in the sidebar. (You may need to scroll down.)
2. Select your iPhone in the list of sound input devices. 
3. The Continuity app opens on your iPhone and starts capturing audio."

Regards.

Hi stephenbunch,

We are glad to hear you were able to find the settings. If you need anything else, don't hesitate to reach out in Apple Support Communities.

Kindest regards!