Ok I tried this tutourial but the game audio is much louder than my mics. Help please?
Do you record Commentary with FRAPS? or do you use Audacity etc. to record commentary?
If FRAPS: you have to set the audio levels in game and check whether the levels are fine. IF they're still too high, lower the volume in the game even more and so on. Note that in game audio levels may increase when there's a lot of action going. That's why most prefer to use audio recorders like Audacity so that they can adjust the levels properly.
If Audio Recording software: You adjust the audio levels in video editing software.