Noise, Vibration and Harshness (NVH)

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.

Hz (Hertz):

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.