Glossary of Terms: Amplitude

The quantity or amount of energy produced by a vibrating component (G-force). An extreme vibration has a high amplitude. A mild vibration has a low amplitude. See INTENSITY .

Boom 

Low frequency or low pitched noise often accompanied by a vibration. Also refer to DRUMMING below.

Buffet/Buffeting 

Strong noise fluctuations caused by gusting winds. An example would be wind gusts against the side glass.

Buzz 

A low-pitched sound like that from a bee. Often a metallic or hard plastic humming sound. Also describes a high-frequency vibration. Vibration feels similar to an electric razor.

Chatter 

A pronounced series of rapidly repeating rattling or clicking sounds.

Chirp 

A short-duration, high-pitched noise associated with a slipping drive belt.

Chuckle 

A repetitious, low-pitched sound. A loud chuckle is usually described as a knock.

Click 

A sharp, brief, non-resonant sound, similar to actuating a ball point pen.

Clonk 

A hydraulic knocking sound. Sound occurs with air pockets in a hydraulic system. Also described as hammering.

Clunk/Driveline Clunk 

A heavy or dull, short-duration, low-frequency sound. Occurs mostly on a vehicle that is accelerating or decelerating abruptly. Also described as a thunk.

Conductor 

The components that carry (transmit) a vibration frequency from the originator to the reactor.

Cycles Per Second 

Cycles per second. Same as hertz (Hz).

Cracks 

A mid-frequency sound, related to squeak. Sound varies with temperature conditions.

Creak 

A metallic squeak.

Cycle 

The process of a vibrating component going through a complete range of motion and returning to the starting point.

Decibel (dB) 

A unit of measurement, referring to sound pressure level, abbreviated dB.

Drone 

A low-frequency, steady sound, like a freezer compressor. Also described as a moan.

Drumming 

A cycling, low-frequency, rhythmic noise often accompanied by a sensation of pressure on the ear drums. Also described as a low rumble, boom or rolling thunder.

Flutter 

Mid to high intermittent sound due to air flow. Similar to a flag flapping in the wind.

Frequency 

The rate at which a cycle occurs within a given time.

G-force 

The additional load or weight produced in an object during acceleration. When measuring the level or amplitude of a vibration without sound, the unit G is added to associate the force of the vibration to gravity. This is similar to measuring the weight of an object, which is also a function of gravity.

Gravelly Feel 

A grinding or growl in a component, similar to the feel experienced when driving on gravel.

Grind 

An abrasive sound, similar to using a grinding wheel, or rubbing sand paper against wood.

Hertz (Hz) 

A unit of measure used to describe noise and vibration concerns expressed in cycles per second.

Hiss 

Steady, high-frequency noise. Vacuum leak sound.

Hoot 

A steady, low-frequency tone, sounds like blowing over a long neck bottle.

Howl 

A mid-range frequency noise between drumming and whine. Also described as a hum.

Hum 

Mid-frequency steady sound, like a small fan motor. Also described as a howl.