An acceptable frequency response is a range of frequencies that a system is able to reproduce accurately. This range varies depending on the application and the quality desired, but is generally 20 Hz - 20 kHz for audio systems. Anything outside of this range is usually considered to be distorted and will not sound as intended. Many factors can affect the frequency response of a system, such as the type and quality of components used, so it is important to carefully consider these when designing or choosing one.