An audio signal processing apparatus for processing an input earpiece audio signal (x) upon the basis of a microphone audio signal (y), the input earpiece audio signal (x) being associated with the microphone audio signal (y), the audio signal processing apparatus comprising: a voice activity detector being configured to determine a voice activity indicator signal (x vad) upon the basis of the input earpiece audio signal (x), wherein the voice activity indicator signal (x vad) indicates a magnitude of a voice component within the input earpiece audio signal (x); a noise magnitude determiner being configured to determine a microphone noise magnitude indicator signal (w y) upon the basis of the microphone audio signal (y), wherein the microphone noise magnitude indicator signal (w y) indicates a magnitude of a noise component within the microphone audio signal (y); a gain factor determiner being configured to determine a gain factor signal (Δ G) upon the basis of the voice activity indicator signal (x vad) and the microphone noise magnitude indicator signal (w y), wherein the gain factor signal (Δ G) indicates a gain associated with the input earpiece audio signal (x); and a weighter being configured to weight the input earpiece audio signal (x) by the gain factor signal (Δ G) to obtain an output earpiece audio signal; characterised in that the gain factor determiner is further configured to determine the gain factor signal (Δ G) according to the following equation: Δ G n = x vad n w y n η w y wherein Δ G denotes the gain factor signal, w y denotes the microphone noise magnitude indicator signal, η wy denotes a predetermined noise magnitude threshold, x vad denotes the voice activity indicator signal, and n denotes a sample index. a voice activity detector being configured to determine a voice activity indicator signal (x vad) upon the basis of the input earpiece audio signal (x), wherein the voice activity indicator signal (x vad) indicates a magnitude of a voice component within the input earpiece audio signal (x); a noise magnitude determiner being configured to determine a microphone noise magnitude indicator signal (w y) upon the basis of the microphone audio signal (y), wherein the microphone noise magnitude indicator signal (w y) indicates a magnitude of a noise component within the microphone audio signal (y); a gain factor determiner being configured to determine a gain factor signal (Δ G) upon the basis of the voice activity indicator signal (x vad) and the microphone noise magnitude indicator signal (w y), wherein the gain factor signal (Δ G) indicates a gain associated with the input earpiece audio signal (x); and a weighter being configured to weight the input earpiece audio signal (x) by the gain factor signal (Δ G) to obtain an output earpiece audio signal; characterised in that the gain factor determiner is further configured to determine the gain factor signal (Δ G) according to the following equation: Δ G n = x vad n w y n η w y wherein Δ G denotes the gain factor signal, w y denotes the microphone noise magnitude indicator signal, η wy denotes a predetermined noise magnitude threshold, x vad denotes the voice activity indicator signal, and n denotes a sample index.