In one embodiment, an audio system can generate a parametrically formulated noise signal which can be mixed with an audio signal or acoustic signal. According to an embodiment, a parametrically formulated noise signal can be configured to have a power spectrum amplitude that is a function of frequency. According to an embodiment, a parametrically formulated noise signal can have a power spectrum amplitude across a range of frequencies that is a function of an individual's hearing thresholds across the range of frequencies.