The present invention relates to a method for attenuating undesired content in an audio signal and to an apparatus adapted to attenuate undesired content in an audio signal. The invention may be used to reduce adverse effects on a user caused by undesired or potentially harmful audio signals received from an audio communication network, such as e.g. a telephone network, and may advantageously be implemented in headsets and other audio communication apparatus that can receive audio signals from an audio communication network and provide corresponding sound signals to one or more users.The present invention provides a method for attenuating undesired content in an audio signal. The method comprises: receiving an audio input signal (Si); providing a main audio signal (Sa) in dependence on the audio input signal (Si); determining an input level signal (Ln) indicating a signal level (Ln,i) of the main audio signal (Sa) for each of multiple frequency subbands; applying a frequency-dependent gain to the main audio signal (Sa) to provide an audio output signal (So); providing an analysis signal (Sn) in dependence on the audio input signal (Si); determining a classification signal (Sc) indicating the presence in the analysis signal (Sn) of one or more audio signals belonging to a first predefined audio signal class; determining a threshold control signal (St) indicating a frequency-dependent level threshold (72, 75, 76, Tf) for multiple frequency subbands in dependence on the classification signal (Sc); and determining the frequency-dependent gain in dependence on signal levels (Ln,i) indicated by the input level signal (Ln) and the frequency-dependent level threshold (72, 75, 76, Tf) indicated by the threshold control signal (St). The method is characterized in that the frequency dependency of the frequency-dependent level threshold (72, 75, 76, Tf) indicated by the threshold control signal (St) depends on the classification signal (Sc).This may provide an improved method for attenuating undesired content in an audio signal.