Garageband on macbook connects to my phone microphone and I can't get it to stop

Hi nickchou,

For help with checking and changing your microphone settings, test the steps below found in the article here: Use your iPhone as a webcam on your Mac - Apple Support

"Use your iPhone as a webcam or microphone

1. On your Mac, open any app that has access to the camera or microphone, like FaceTime or PhotoBooth.
2. In the app’s menu bar or settings, choose your iPhone as the camera or microphone.
3. The Continuity app opens on your iPhone and begins capturing audio or video from the rear camera.
4. Note: In order to use your iPhone as a microphone on a Mac without a built-in camera, the iPhone must be in landscape orientation, stationary, and locked.
5. Do any of the following:

• Pause the video or audio: On your iPhone, tap Pause, or swipe up to unlock it.
• Resume the video or audio: On your iPhone, tap Resume, or press the side button or Sleep/Wake button to lock it.
• Stop using your iPhone as a webcam or microphone: On your Mac, quit the app.
• Remove your iPhone as an option: On your iPhone, tap Disconnect. Your iPhone is removed from the camera and microphone lists in apps, and also from the list of sound input devices in Sound settings."

The section "Make your iPhone the default microphone" in the same article also has helpful information. Find helpful access settings here as well: Control access to the microphone on Mac and here: Control access to hardware features on iPhone

Cheers.