Abstract: An amplitude responsive detection system analyzes the amplitude characteristic of a received noise and determines whether that characteristic conforms to the predictable audio signature of a gunshot. If a received noise reaches a predetermined amplitude level within a rise time that may be indicative of a gunshot, subsequent amplitude criteria are established representing the decay of the amplitude profile that is expected if the noise is a gunshot. The amplitude criteria are controlled as to both level and occurrence in time to provide a dynamic range that will accommodate near and far gunshots.