Definition of Noise, Vibration, and Harshness

Noise, vibration and harshness (NVH) are becoming more important as vehicles become more sophisticated and passenger comfort levels increase. This is designed to aid in the diagnosis, testing and service of NVH concerns.
- Sounds that are unpleasant or unwanted are called noise. The vibrational energy in a structure is transformed into air pressure waves which are detected by the ear. Noise can be very subjective in nature.
- Vibration is mechanical oscillation about a reference point. It is typically an unwanted by-product of some useful process.
- Vibrations are tactile inputs through driver interface points in a vehicle such as steering wheel, seat, floorpan, armrest, etc.
- Harshness is a ride quality issue where the customer feels that the vehicle response to the road surface is sharply transmitted to the customer.