How do you change the microphone Mac dictation uses?

To change the microphone Mac dictation uses, go to System Settings > Keyboard > Dictation, and choose the device in the Microphone source menu. Apple's steps for this are in its current Dictation guide, and the menu names can change between macOS versions. If the Mac has no built-in microphone, connect an external one before you start, then select it in Sound settings too and raise its input volume.

Keyboard settings chooses the microphone for Dictation

Dictation has its own microphone menu. Apple says the microphone source in Keyboard settings shows which device your Mac is currently using to listen for Dictation ¹. To change it, choose Apple menu > System Settings, click Keyboard in the sidebar (you may need to scroll down), go to Dictation, and click the pop-up menu next to Microphone source. Then choose the microphone you speak into ².

Set it here when the problem is with Dictation. The Microphone source menu is the place to look first, before you change anything else in the system.

Automatic is the Mac's guess, and it can be wrong

On Automatic, your Mac listens to the device it thinks you are most likely to use for Dictation ². For a Mac with only a built-in microphone, Automatic is a sensible default. Once you add headphones, a webcam or an external microphone, the guess can land on the wrong device. Choose the microphone by name when Dictation ignores the one you are speaking into.

Sound settings sets the input and its level

The Dictation menu tells Dictation which device to listen to. It does not set how loud that device is. Apple's troubleshooting says that if your Mac does not respond to your voice, you should select the microphone in Sound settings and increase its input volume ³. For an external microphone, Apple also says to make sure its input volume is sufficient ⁴. Apple gives no number for a sufficient level, so test by dictating a sentence in Notes after each change.

A Mac without a built-in microphone needs an external one first

If the Mac has no built-in microphone, Apple says to connect an external microphone and select it in Sound or Keyboard settings ⁵. If you have just set up a Mac that has no microphone inside, connect the microphone first, then open the Dictation menu again so the device appears in the list.

AirPods and Bluetooth headsets lower the audio quality

When a headset's microphone is in use, Bluetooth switches to a second mode, and Apple says audio quality is reduced until the microphone is no longer in use ⁶. A reduced signal gives the recognizer less to work with, so Dictation can get worse whenever a headset's microphone is the one in use. If that happens, choose the built-in microphone in the Microphone source menu and test again. Use the headset only when the built-in microphone is not good enough.

Distance matters more than which microphone you pick

Where the microphone sits changes the result. In a 2017 study of distant speech recognition, close-talking read speech recorded in a studio had a word error rate of 3.7 percent ⁷. A single distant microphone in a real apartment had a word error rate of 12.0 percent ⁸. That study used a different recognizer from Apple's, so read it as a direction and not as Apple's own figures. For how close a headset should sit, see how close a dictation microphone should be.

When only one app ignores the microphone

If Dictation works in Notes but not in one other app, the microphone choice is probably fine, and the problem is that app's microphone access. Open System Settings, click Privacy & Security, click Microphone, and turn on access for that app. Quit and reopen the app afterward. The app-level check is covered in why Mac dictation is not working.

The steps in order

1. Connect an external microphone if the Mac has no built-in one.
2. Open Keyboard settings, go to Dictation, and choose the device in Microphone source.
3. Open Sound settings, select the same microphone, and raise its input volume.
4. Test a sentence in Notes.
5. If it fails, change only one setting, then test again, so you know which change fixed it.

If the microphone is right and Dictation still stops, read why Mac dictation keeps stopping. If it still fails in every app, the whole checklist is in why Mac dictation is not working. The general microphone question for all devices is answered in is a laptop microphone good enough for dictation, and the guide to the feature itself is how to use Dictation on a Mac, part of dictation on Mac.