Beats- A throbbing variation in the loudness of sound caused by interference when two tones of slightly caused by interference are sounded together.
Compression- In mechanics, the act of squeezing material and reducing its volume. In sound, a pulse of compressed air(or other matter);opposite of rarefaction.
Forced vibration- The vibration of an object that is made to vibrate by another vibrating object that is nearby. The sounding board in a musical instrument amplifies the sound through forced vibration.
Infrasonic-Term applied to sound pitch too low to be heard by the human ear, tht is, below 20 hertz.
Natural frequency_A frequency at which an elastic object, once energized, whill vibrate. Minimum energy is required to continue vibration at the frequency. Also called resonant frequency.
Pitch- Term that refers to how high or low sound frequencies appear to be.
Rarefaction- A disturbance in air(or matter) in which the pressure is lowered. Opposite of compression.
Resonance - A phenomenon that occurs when the frequency of forced vibrations on an object matches he object's natral frequency, and a dramatic increase in amplitude resu
Ultrasonic- Term applied to sound frequencies above 20,000 hertz, the normal upper limit of human hearing.