Hi MPUers, so I usually keep my sound input to zero when I’m not using the mic which is most of the day. I only turn it on when I use the microphone during meetings. I recently turned on the dictation feature on macOS, and even with the sound input zero, the dictation feature seems to work, so does it mean that macOS can still hear you even with the sound zero, this seems weird!
I don’t know the reason behind it, but setting your sound input to “0” doesn’t actually mute the microphone, and even doing it via AppleScript doesn’t really mute it completely. That’s why I rely on third-party software to mute the system mic. Alternatively, you could create a virtual input via the Audio MIDI Setup app, but without configuring a microphone, and just switch to it when you don’t want any audio input.
Since dictation has its own setting for microphone input I guess it sets the input volume level automatically regardless of the input level in sound settings, so you can always use, even if you muted your system accidentally.