As a Firefox Support Forum contributor, I can help you with your question about using the microphone in the Firefox search bar.

To enable the microphone in the Firefox search bar, you need to ensure that your operating system and browser settings are properly configured. Here are the steps you can follow:

Check your microphone settings in Windows 10:

Click on the Start menu and select "Settings." In the Settings window, click on "Privacy." On the left sidebar, click on "Microphone." Make sure that the "Allow apps to access your microphone" toggle is turned on. Scroll down to the "Choose which Microsoft Store apps can access your microphone" section and ensure that Firefox is listed and enabled. Verify Firefox permissions:

Open Firefox and type "about:preferences" in the address bar. Go to the "Privacy & Security" section. Scroll down to the "Permissions" section and click on "Settings" next to "Microphone." Make sure that the correct microphone device is selected and that the permission for Firefox to access the microphone is granted. Once you have checked and adjusted these settings, you should be able to use the microphone in the Firefox search bar. If you continue to experience issues, feel free to provide more details, and I'll be happy to assist you further.

this does not work as firefox does not appear in microphone settings in win 10

Currently, I don't think Firefox has built-in microphone functionality for any text input fields. Maybe there's a hidden accessibility setting that someone can mention but I don't see it in the main article: Accessibility features in Firefox - Make Firefox and web content work for all users.

You can use Windows' Dictation feature (Windows key + H) in web page forms, but from what I can see, it does not turn on in the address/search bar (in Firefox's toolbar area).

If you intend to search from the built-in Firefox Home / new tab page, you can change a setting so that instead of moving the cursor to the address bar, it stays in the web pages, allowing use of Windows Dictation there. Here's how:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. Since I use this one myself, I feel comfortable mentioning it.

(2) In the search box in the page, type or paste handoff and pause while the list is filtered

(3) Double-click the browser.newtabpage.activity-stream.improvesearch.handoffToAwesomebar preference to switch the value from true to false

Maybe that will be somewhat useful.