All the other samples are very similar to the ones displayed above, so we will omit their graphs. As we notice, most of the power is located below 700 Hz for the female voice, and below 500 Hz for the male voice (the amplitude is in log scale). These results are confirmed by our literature [9], which states that the voced speed of a typical adult male has a fundamental frequency of 85 to 155 Hz, and the voiced speech of typical adult female has a fundamental frequency of 165 to 255 Hz.