Quick fix: Voice Access uses the system default capture device, not the per-app one you set in Settings → Sound. Set the default explicitly: open mmsys.cpl → Recording tab, right-click the mic you want, and choose Set as Default Device. Voice Access picks it up at the next launch.

You enabled Voice Access for hands-free typing. It hears you when you say “Voice Access wake up” but transcribes garbage as soon as you start dictating. Your built-in laptop mic is being used instead of the high-quality USB headset mic you wanted. The headset is set as default for some apps but not for Voice Access — it’s reading the system default, and the system default never changed.

Symptom: Voice Access transcribes incorrectly because it’s using the wrong microphone (typically the built-in instead of a connected headset).
Affects: Windows 11 with Voice Access enabled and multiple microphones available.
Fix time: 5 minutes.

Why Voice Access ignores per-app mic settings

Modern Windows audio has two default-device concepts: Default (used by most apps) and Default Communication Device (used by VoIP apps like Teams, Zoom). The new Settings app lets you also override per-app input under Settings → System → Sound → Volume mixer. Voice Access bypasses all per-app overrides and reads only the system Default Communication Device, with fallback to the regular Default.

If your headset is set as Default for most apps but the built-in mic is still Default Communication Device (or vice versa), Voice Access uses the wrong one. Setting both defaults to the same headset solves it.

Method 1: Set system defaults via the legacy Sound dialog

Press Win + R, type mmsys.cpl, press Enter.
Click the Recording tab.
Find the microphone you want Voice Access to use.
Right-click it and choose Set as Default Device. A green checkmark appears.
Right-click it again and choose Set as Default Communication Device. A phone icon appears next to the checkmark.
Click OK.
Open Voice Access (Win+H or Search). It now uses the headset.

Voice Access reads the default at startup, not continuously. If it was already running, close and reopen it.

Method 2: Set defaults via the new Settings app

Open Settings → System → Sound.
Under Input, click the microphone you want as default. The selection becomes active.
For finer control, scroll to Advanced → All sound devices. Click the microphone and confirm Default audio device shows Default.
The new Settings app doesn’t separate Default from Default Communication. Use Method 1 if you need both set explicitly.

For most cases, Method 2 is enough — Voice Access uses whichever is set. Method 1 is needed only when communication apps and Voice Access need different defaults.

Method 3: Lock the default mic so Windows doesn’t switch on disconnect

USB headsets disconnect when you unplug them, and Windows defaults to the next-best input (usually built-in). When you replug, Windows doesn’t always restore the headset as default.

In the legacy Sound dialog (Method 1), find the headset.
Right-click → Properties → Advanced tab. Confirm Allow applications to take exclusive control of this device is unchecked (sharing is fine).
On the General tab, set Device usage to Use this device (enable).
Disconnect and reconnect the headset. Check if it returns to Default automatically.
If it doesn’t, your USB headset may be enumerated under a different name each time — check Device Manager → Sound, video and game controllers, and look for duplicates with parenthetical numbers.

For USB mics that change device IDs each time they’re plugged in, a third-party tool like SoundSwitch (free, open-source) can auto-set the default whenever the headset appears.

How to verify the fix worked

Open Voice Access. The mic icon at the top reads the correct device name.
Say “Voice Access listen.” The wake response shows it heard the right mic.
Dictate a sentence into Notepad. The transcription is accurate.
Disconnect and reconnect the headset. Voice Access still uses it (not the built-in) on next launch.

If none of these work

If Voice Access still uses the wrong device, restart the Speech Recognition Service via services.msc. If the default is set correctly in Sound but Voice Access ignores it, your Windows install may need the latest Voice Access engine update — check Settings → Accessibility → Speech → Voice Access for a Manage languages link, and update if available. For consistent mic switching with Bluetooth headsets, disable Hands-Free AG Audio on the headset properties — Voice Access works better with the stereo (A2DP) profile than the hands-free (HFP) one.

Bottom line: Voice Access reads system defaults, not per-app overrides. Set both Default and Default Communication to the same headset, restart Voice Access, and dictation improves dramatically.