Some taxes are inadvertently hidden, but others are consciously designed that way to disguise the cost of government. Itâs easy to see why: the total U.S. tax burden is equal to 56 percent of annual personal consumption spending.
Thus, the volume is proportional to the amplitude of the sound wave. The frequency of a sound wave is perceived as pitch. Humans can detect pitches within the acoustic range of 20 to 20,000 Hz, but we can't detect ultrasound or infrasound.
1 The pitch of a note depends on the frequency of the source of the sound. 2  Frequency is measured in Hertz (Hz), with one vibration per second being equal to one hertz (1 Hz).  A high frequency produces a high pitched note and a low frequency produces a low pitched note.