An audio system and method is described to monitor whether the audio processing performed on an audio signal is corrupted. The audio system includes module to embed a watermark into an audio signal, and a verification module to verify the presence of the watermark after the audio processing has been performed. The embedding strength of the watermark can be adjusted on the basis of whether the presence of the watermark is detected. The embedding strength for the watermark may be adjusted such that it is as low as possible while still allowing detection, thus keeping the audio quality as high as possible.