If you have more than one Microphone, you may need to make additional adjustments.
Note: You will need to restart Chrome after any changes to audio input or output settings.
At the bottom of your Windows Desktop, Right Click the Speaker icon, and Choose Open Sound settings:
Scroll down to see which device is detected as Default Input:
You may also need to click into the App volume and device preferences, to ensure the correct Mic is being used for Chrome.
Note: You will need to restart Chrome after any changes to audio input or output settings.