Dictation and “Hey, Siri” in macOS Tahoe

Mic Drop mutes your microphone(s) using a standard macOS API that prevents audio from being transmitted to any app/software on the system. It uses the low-level “Core Audio” system that has been around in macOS since 2003.

Apple, of course, can still modify macOS to ignore the fact that a microphone is muted, and does this in two ways starting in macOS Tahoe:

1. Overriding a microphone’s mute state when Dictation input is triggered and preventing Mic Drop from working until you finish dictating text.
2. Listening for the “Hey Siri” keyword on your Mac, even when the microphone is muted.

Dictation in macOS Tahoe

When you hold down the dictation key/start dictation on macOS, Apple overrides the mute flag set on all devices by Mic Drop. Starting in macOS Tahoe, Mic Drop cannot re-mute you until you’ve finished dictation. After that, Mic Drop will instantly & automatically mute all of your microphones again.

“Hey Siri” in macOS Tahoe

“Hey Siri” can also be triggered even when your microphone is muted, but audio from “Hey Siri” does not seem to be transmitted to your system. (If you try recording audio with Voice Recorder on your Mac while Mic Drop is muted, you’ll see that you cannot see audio being transmitted, including when you say “Hey Siri”.)

Does this means apps can listen to me?

No, Mic Drop still keeps you muted even if macOS is listening for the “Hey, Siri” keyword.

Rest assured no other app on the system can hear your mic, but it looks like Apple has changed the way that the low-level code in the operating system handles a muted microphone, and they will override it for dictation, as well maintain the ability to listen for “Hey Siri” even though the mic is otherwise inactive.

You can still reliably mute/unmute with Mic Drop without any issue and trust you’re muted—as long as you don’t open dictation, Mic Drop will keep you muted. And if you do use Dictation—once you close it Mic Drop will set you back to muted, as expected.