OP,
I once had this problem it's an easy fix.
First right click your volume button at the bottom right of your screen.
Second click Recording Devices.
Third make sure the mic you choose is set as default then try and setup mic in game.
(If this doesn't work disable all other recording devices besides the one you want to work on CS)
Fixed my problem and many of my friends hopefully it helps you! :)
I once had this problem it's an easy fix.
First right click your volume button at the bottom right of your screen.
Second click Recording Devices.
Third make sure the mic you choose is set as default then try and setup mic in game.
(If this doesn't work disable all other recording devices besides the one you want to work on CS)
Fixed my problem and many of my friends hopefully it helps you! :)