Hello everyone:
Just thought I would add to this discussion as it may help someone here in the future.
WINDOWS 10 owners with REALTEK HD Audio ( Issue - VERY LOW MIC VOLUME LEVELS):
I have an Asus X-99 Deluxe motherboard with RealTek and Win10 Pro. I have an excellent AntLion microphone that was just never loud enough to get voice recognition to work. After some detective work I discovered that it is common to have abnormally low mic levels with the above PC configuration. Even max volume and mic boost doesn't really get you there, not to mention it sounds terrible!
Unfortunately, if any of you DO have Win 10 and a RealTek HD setup, I have been unable to find a work-around or fix. Using drivers straight from RealTek didn't help, nor did an earlier one from Asus. There may be some solution out there, but I have yet to find it. I felt maybe this will help someone to move on in another direction if it applies to you.
My Personal Solution: I ended up purchasing a Blue Yeti 4-way desktop mic (that I can use for future podcasting, etc.) as a stand-in. I had just bought Tower!3D Pro August 4th and was peeved that I could not get voice recognition up and running. Anyway, using the Cardioid setting with gain at ~70% did the trick. I spent about an hour "teaching" Win 10 my voice with the training sessions. You can do them again and again to help refine the VR. I am very happy with the results so far in Tower!3D Pro.
I know a desktop mic isn't the recommended solution for VR, but I have HiFiMan HE-560 headphones that are absolutely superb, so a separate mic is a must for me. Honestly, I don't have any issues with external noise ruining the recognition, even with my PC's noticeable fan noise.
Hope this helps.
Paul