Vibration is the oscillation of an object about a static position. Vibrations typically, as in the case of a speaker diaphragm, produce sound. More often, however, vibrations are not necessarily desired as in the case of air conditioning equipment inducing vibrations which propagate through a building.

Vibration is measured with an accelerometer. An accelerometer is a device that is securely attached by some means to a surface and produces an electrical signal which is proportional to the surface acceleration. This signal is measured by a meter and can be expressed in terms of acceleration, velocity, or displacement of the surface. When making vibration measurements, the frequencies of interest generally range from below 1 hertz to about 1 kilohertz.