Linearity would predict an invariant ratio of gain to input voltage in an audio device such as an amplifier. Manifested as harmonic distortion and intermodulation distortion, there is a point at which the amplifier gain is reduced as the input gain is increased. This is the nonlinear region of the amplifier. All audio devices have local peculiarities or deviations from linearity at specific signal levels. See also distortion, linear distortion.