Beats: Athrobbing variation in the luodness of sound caused by interference when two tones of slightly different frequencies 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.
Force 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, that is, below 20 hertz.
Natural frequency: A frequency at which an elastic object, once energized, will vibration at the frequency. Also called reasonant frequency.
Pitch: Term that refers to ho 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 the objects natural frequency, and a dramatic increase inamplitude results.
Ultrasonic: Term applied to sound frequencies above 20 000 hertz, the normal upper limit of human hearing.