Audio engineers select amplifiers that provide enough headroom. Headroom refers to the amount by which the signal-handling capabilities of an audio system exceed a designated nominal level. Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the nominal level without damaging the system or the audio signal, e.g., via clipping. Standards bodies differ in their recommendations for nominal level and headroom. Selecting amplifiers with enough headroom helps to ensure that the signal will remain clean and undistorted.