NVH Terms | NVH Terminology | Popular NVH Glossary List

NVH Terminology / NVH Glossary

NVH Terms is a term for the interpretation of vehicle noise, vibration and harshness contributing to varying degrees of discomfort what the people can hear and feel as they drive along, including wind noise, road noise, suspension bumps, engine vibrations.

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NVH Terms | Popular NVH Terminology | NVH Glossary

Audible Range of Sound – NVH Terminology

Sounds that are in the range of 20 to 20,000 Hertz (Hz).

NVH Terminology - Audible range of sound - Pitch intensity sound - Soundwaves - NVH noise level
NVH Terminology – Audible range of sound – Pitch intensity sound – Soundwaves – NVH noise level

 

Amplitude

The vertical measurement between the top and bottom of a wave. Also see magnitude.

Amplitude Sound Cycle - NVH Terminology
Amplitude Sound Cycle – NVH Terminology
Vibration amplitude - Sound waves - Vibration level
Vibration amplitude – Sound waves – Vibration level

 

 

Beat

An NVH concern produced by two sounds that is most noticeable when the frequency difference is 1 to 6 Hz.

Bead Seating

The process of seating the tire to the rim. If properly lubricated the bead seating occurs when the tire and wheel are assembled.

Compelling Force

A vibrating object acting upon another object that causes the other object to vibrate.

Vibration - Compelling force beat - Bead seating - Reliability analysis - Durability analysis
Vibration – Compelling force beat – Bead seating – Reliability analysis – Durability analysis

 

Cycle

The path a wave travels before the wave begins to repeat the path again.

Dampen

To reduce the magnitude of a noise or vibration.

Dampers

A component used to dampen a noise or vibration. Foam and rubber are commonly used to dampen vibrations.

Damping System - Dampers - Suspension system - Dampen noise - Dampen vibration - Dynamic balance
Damping System – Dampers – Suspension system – Dampen noise – Dampen vibration – Dynamic balance

 

Dynamic Balance

A procedure that balances a tire and wheel assembly in two planes. Dynamic balance removes radial and lateral vibrations.

Droning, High-Speed

A long duration, non-directional humming noise that is uncomfortable to the ears and has a range of 50 mph (80.5 kph) and up.

Droning, Low-Speed

A long duration, low-pitched noise that is non-directional and has a range of up to 30 mph (48 kph).

Droning, Middle-Speed

A long duration, low-pitched noise that is non-directional and has a range of 30 to 50 mph (48 to 80.5 kph).

Droning - Nondirectional noise - Low pitched noise
Droning – Non directional noise – Low pitched noise

 

Electronic Vibration Analyzer

An electronic NVH diagnostic tool that measures frequency and amplitude.

Frequency

The number of complete cycles that occurs in a given period of time.

Harshness

An aggressive suspension feel or lack of give in response to a single input.

Harshness - NVH harshness and vibrational analysis - Lack of suspension feel
Harshness – NVH harshness and vibrational analysis – Lack of suspension feel

 

Hertz

The unit of frequency measurement in seconds (a vibration occurring 8 times per second would be an 8 Hz vibration).

Intensity

The physical quality of sound that relates to the amount and direction of the flow of acoustic energy at a given speed.

Intensity - Direction flow acoustic energy
Intensity – Direction flow acoustic energy

 

Lateral Run out

A condition where a rotating component does not rotate in a true plane. The component moves side-to-side (wobbles) on its rotational axis.

Lateral run out - Number of disturbances - Vibration order
Lateral run out – Number of disturbances – Vibration order

 

Magnitude (Amplitude) – NVH Terminology

The amount of force or the intensity of the vibration. The magnitude or strength of a vibration is always greatest at the point of resonance.

Magnitude - Amplitude - Resonant - Resonance frequency - Intensity of vibration
Magnitude – Amplitude – Resonant – Resonance frequency – Intensity of vibration

 

Medium

Provides a path for sound waves to travel through.

Natural Frequency

The frequency that a component will vibrate the easiest. Normally, the larger the mass, the lower its natural frequency.

  • Engine block (2-4 Hz)
  • Tire and wheel assemblies (1-15 Hz) – proportional to vehicle speed
  • Suspension (10-15 Hz
  • Driveline (20-60 Hz)
  • Differential components (120-300 Hz)

Noise

The unpleasant or unexpected sound created by a vibrating object.

NVH Terminology - Noise - NVH noise - Types of noise - Car noise - Unexpected sound
NVH Terminology – Noise – NVH noise – Types of noise – Car noise – Unexpected sound

 

Order

The number of disturbances created in one revolution of a component.

Phase

The position of a vibration cycle relative to another vibration cycle in the same hertz rate (time frame).