<p>An audio processing application is provided which utilizes an audio codec encode/decode simulation system and a psychoacoustic model to estimate audible quantization noise that may occur during lossy audio compression. Mask-to-noise ratio values are computed for a plurality of frequency bands and are used to intelligently process an audio signal specifically for a given audio codec. In one exemplary embodiment, the mask-to-noise ratio values are used to reduce the extent of perceived artifacts for lossy compression, such as by modifying the energy and/or coherence of frequency bands in which quantization noise is estimated to exceed the masking threshold.</p>