The iPhone 4 is the second smartphone (by our count) to have dual microphones to allow for noise cancellation. So, does it work? In this audio demonstration you get to hear how the iPhone 4 handles three noisy environments: standing next to a loud air conditioner, standing near a fan (to simulate windy conditions), and being near extremely loud music (to simulate being at a concert, loud bar, or stadium). As you can hear, the noise cancellation does work, though it often takes the iPhone 4 several seconds to cut down the noise. And sometimes, because of this lag, once in a more quiet area, the iPhone isn't always fast enough at dropping the noise cancellation, resulting in a robotic-sounding voice for several seconds. What do you think about the noise cancellation of the iPhone 4? Is it any good?