Overtones and timbre

Sound waves generated during speech and musical instruments are not pure sine waves. They are complex waves which includes fundamental tones and their harmonics. Sound with frequencies other than the fundamental is called overtones. Through telephone, when we hear the sound of a friend, we automatically recognize even if the person is not visible to us. This specialty of human character is called timbre. Timbre is related to the proportion in which overtones are present in the sound. Human beings have fundamental frequencies between 110 to 1500 Hz. Female voice is low in intensity because of lack of low frequency contents below 220 Hz.