Beats: When two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud - a phenomenon which is called "beating" or producing beats.
Compression: In mechanics, compression is the application of balanced inward forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions.
Forced Vibration: This is an example of resonance - when one object vibrating at the same natural frequency of a second object forces that second object into vibrational motion. The result of resonance is always a large vibration.
Infrasonic: relating to or denoting sound waves with a frequency below the lower limit of human audibility.
Natural Frequency: The frequency or frequencies at which an object tends to vibrate with when hit, struck, plucked, strummed or somehow disturbed is known as the natural frequency of the object.
Pitch: The sensation of a frequency is commonly referred to as the pitch of a sound. A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low frequency sound wave.
Rarefaction: Rarefaction is the reduction of an item's density, the opposite of compression. Like compression, which can travel in waves, rarefaction waves also exist in nature.
Resonance:n physics, resonance is the tendency of a system to oscillate with greater amplitude at some frequencies than at others. Frequencies at which the response amplitude is a relative maximum are known as the system's resonant frequencies, or resonance frequencies.
Ultrasonic : involving sound waves with a frequency above the upper limit of human hearing.