I think it only has one, but my samsung bluetooth has 2 for noise cancelation. I don't like where HTC put it on the n1. My sister has an n1, and she didn't realize she sounded like crap on it cause she covered the mic on the back with her hand. Its a great idea, but I like it more on the bluetooth than I do on the unit. I also noticed when I drive my mom's car, it has built in noise cancellation. Nothing heard from the car itself gets transmitted through, like turn signal noise, GPS notifications or even road noise. Its quite nice.