The Nyquist-Channen Theorem: How to Record Silence

A digital sample is just one thing. It's just a number to indicate how hard the air is pushing or pulling at the particular instant at which you sample the sound. To represent a sound with a sequence of discrete numerical samples, you have to sample at twice the rate of the fastest or highest sound that you want to record because you need to capture information about the peak and the trough of the wave. You have to get at least two samples per acoustical cycle.