Apparatus for producing a plurality of audio sound effects such as shots, explosions, and airplane and car sounds, used in electronic games utilizes a variable clock driving a variable digital noise generator whose audio output amplitude is shaped by either of two types of control units. In one type the density or duty cycle is varied by selectively ANDing together outputs from a polynomial counter. In a second embodiment a digital to analog converter utilizing gated resistive summing provides the amplitude control the gates being driven by a four bit data register which in turn is driven by the game control means.