I wanted to address this problem as I was having the same problem, however the fix that worked for me was completely unrelated to solution in here. Note that my issue was specifically that I could hear through my headphones, but when plugging in the mic line, windows wasn't picking up my voice. I'll describe the problem and the solution.
I have a case that supports two front jacks, one for a headset and one for a mic. The SteelSeries Sibera v2 don't use USB, but rather two separate jacks for the headset and the mic, although physically the mic is obviously attached to the headphones. I have an MSI board that comes with its own software separate from the windows audio drivers. Since MSI has its own software, windows treated it as the main source and then fed it back to the windows drivers. So the issue is that the MSI software was telling windows I ONLY had a headset connected, but still detected the mic was plugged in! I realized in the MSI driver/program settings that the default setting for recording devices was to "Tie up the same type of input jacks, i.e. in-line or microphone as input device". This is the INCORRECT setting to use! Below it, there is a box that has the description "Separate all input hacks as independent input devices." This is the CORRECT setting to use!
This forces the windows audio driver to see two separate devices (or channels), a headset and a microphone. This will reflect in playback/recording devices. Phew, now windows recognizes an independent microphone as a recording device! Now at this stage, windows sees a microphone, however it still isn't picking up my voice. It is at this stage that you MUST open up the Advanced Speech Settings found in control panel ->speech recognition-> advanced speech options.
In this dialog, you have (at the bottom of the dialog) an Advanced... option. When you open that, you get to the final dialog, which is Audio Input Setting. It is HERE that you MUST tell windows NOT TO USE THE PREFERRED AUDIO INPUT DEVICE, but to select "USE THIS AUDIO INPUT DEVICE". From this drop down, select the microphone that we enabled through the MSI software, which in my case windows sees the microphone now on the pink front port. When we reach this stage, and hit Ok/Apply, windows will now listen to this device and accept it as a recording device!
Finally, go back into recording devices, go into the Properties section of the recording device, to the Levels tab in the dialog, and turn up the level and you should be good to go!