NVH Terms | NVH Terminology | NVH Glossary

Pitch – The physical quality of sound that relates to the frequency of the wave.

01-pitch-belt squeaking creates high frequency high pitched noise-roller bearing makes low frequency low pitched noise

Radial Force Variation (RFV) – A measurement of the tire’s uniformity, under load, in regards to the variation of the load acting towards the center of the tire; commonly referred to as the tire’s sidewall variation.

01-lateral run out-number of disturbances-vibration order

Radial Run out – A condition where a rotating component does not rotate in a true plane. The component moves up and down on its rotational axis.

Resonance – The tendency of a system to respond increasingly to a compelling force oscillating at, or near, the natural frequency of the system. This causes a sudden and large vibration.

01-vibaration-compelling force-beat-bead seating-reliability analysis-durability analysis

Road Noise – A noise that occurs while driving on gravel or roughly paved roads at all vehicle speeds, or when a vehicle is coasting.

01-harshness-nvh harshness-lack of suspension feel

Shake, Lateral – A side-to-side vibration of the body, seats, and steering wheel.

Shake, Vertical – An up and down vibration of the body, seats, and steering wheel.

01-Vehicle Shake-Steering wheel shake-vibration in steering wheel-vertical shake-lateral shake

Shimmy, High-Speed – A vibration that causes the steering wheel to oscillate when driving on smooth roads at high speeds.

Shimmy, Low-Speed – A vibration that causes the steering wheel to oscillate when driving across a bump at low speeds.

01-shimmy-steering wheel to oscillate-high speed shimmy-low speed shimmy-due to roughness of road-tire imbalance

Source Component – The component that is diagnosed as being the root cause of a vibration or noise concern.

Sound – The result of a vibrating disturbance of an object, which produces waves that transmit out from the source.

01-noise-nvh noise-types of noise-car noise-unexpected sound

Static Balance – The method of balancing a tire and wheel assembly in a single plane. Static balancing removes only the lateral (side to side, wobble) imbalance and the tire and wheel assembly could possibly have a radial (up and down) vibration.

Torque Sensitive Vibration or Noise – A vibration or noise that is sensitive to different loads and torque, applied to the drive train of a vehicle. The vibration or noise changes when the throttle position or transmission gearing is used, during a road test, to change the torque applied to the drive train.

Vibration – The repetitive motion of an object, back and forth or up and down, which may be felt or heard.

01-automotive-NVH-brakeSqueal-vehicle NVH-brake squeal analysis-finite element analysis-vibration force-shudder

Wheel Diameter – The dimension of a wheel measured on the inside of the wheel at the bead seat area.