Comparing WMA and HE AAC Audio Coding

National Software Testing Labs (NSTL), employed by Microsoft, ran a proctored double-blind test that compared 64 kilobits per second (Kbps) WMA Pro (stereo) to the High Efficiency AAC Profile (HE AAC). The 12 segments of audio were presented by a proctor in a double-blind test to 300 individual listeners of both sexes and over a wide variety of ages. The paper states that 37% of the listeners preferred WMA Pro, 34% expressed identical preferences, and 29% preferred HE AAC.