Abstract: A noise reduction system for a sound reproduction system, in particular for hearing aids, comprises a primary and a secondary microphone for producing input signals in response to sound in which a noise component is present. The system has a first signal processing section comprising a fixed filter and a summing function, wherein the first signal processing section has means for receiving signals from the microphones and producing a speech reference signal and a noise reference signal. A second signal processing section comprises an adaptive filter and an additional summing function, and the second signal processing section has means for receiving the speech and noise reference signals and producing an output signal with an improved signal-to-noise ratio.