The High fidelity (short form of hi-fi or hifi) reproduction is a term used by home stereo listeners, audiophiles and home audio enthusiasts to refer to high-quality reproduction of sound to distinguish it from the lower quality sound produced by inexpensive audio equipment, or the inferior quality of sound reproduction that can be heard in recordings made until the late 1940s. Ideally, high-fidelity equipment has inaudible noise and distortion, and a flat frequency response within the intended frequency range.