The frequency range for the microphone is 100Hz-12,000Hz(12kHz). Most people cant talk like tinkerbell or a subwoofer, so it's a pretty good range. From my use with it, it's perfect. You do have to speak up a little for it to catch your voice, whispers generally won't make it, but you may be able to edit that in your computer during setup.
If you're wondering, the headphones have a freq. range of 20Hz-20,000Hz(20kHz). Doing personal tests, it meets if not exceeds that range, but it's rare that you'll likely hit 20Hz or 20,000Hz doing whatever you may be doing (gaming presumably).