Google Meet generates a specific kind of frustration: you set your microphone in macOS, you set it again inside Meet, and Meet keeps using something else anyway. The reason is a settings layer most people don't know exists — Meet runs in a browser, and the browser has its own microphone opinions that sit between macOS and the meeting.
Three layers, not two
For a native app like Zoom, there are two places a mic can be chosen: macOS and the app. For Meet there are three:
1. macOS System Settings → Sound → Input. The system default, and the one most people change first.
2. The browser's own device preference. Chrome and Safari each keep per-site microphone permissions and a preferred-input setting. In Chrome: Settings → Privacy and security → Site settings → Microphone. There's a dropdown there that overrides your system default for web pages, and a per-site list where meet.google.com has its own entry.
3. Meet's in-call settings. The gear icon during a call, which picks among whatever the browser is willing to hand it.
The classic failure: you change macOS, Meet doesn't budge, because Chrome's site setting is pinning something else. Fix layer 2 and layers 1 and 3 usually fall into line.
The permission trap
If Meet shows no microphones at all, or a permission error, the block is usually macOS-level rather than browser-level: System Settings → Privacy & Security → Microphone, and confirm your browser is toggled on. A browser denied at the OS level will show an empty device list rather than a helpful error, which sends people hunting in entirely the wrong place.
Why your mic changes between meetings
macOS re-picks the default input whenever devices appear or disappear — connect AirPods for music and your next Meet call may quietly switch to their microphone, which sounds dramatically worse than your desk mic (there's a real technical reason for that). Browsers inherit that shuffle. This is the same device-roulette problem we mapped for macOS audio settings generally.
The stable answer
Every one of these mysteries has the same root: apps and browsers bind to one physical device, and physical devices come, go, and get reshuffled by the OS. A virtual device that never changes identity removes the whole class of problem. SoundMesh presents one microphone — "SoundMesh Virtual Mic" — that you select once in Chrome's site settings and once in Meet. Behind it, every physical mic you own stays in play, and which one is actually live gets decided continuously based on which hears your voice best. Plug things in, unplug them, connect AirPods for playback; the input your browser sees never changes again.
Bookmark the three-layer checklist for the next time Meet plays dumb. And if you'd rather stop checking layers entirely, the two-mic setup walkthrough gets you there in about twenty minutes.