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.
Pitch is a term used to refer to the height or lowness of a sound. The pitch of a sound is determined by the frequency of the sound waves. A higher pitch has a higher frequency. The noted called A that is the first A above middle C is often used as a note for tuning instruments to match each other, and has the frequency of 440Hz.