FxSound Enhancer (formerly DFX Audio Enhancer) dramatically improves the sound quality of your favorite media players with 3D Surround, higher fidelity, booming bass and more. That provides exceptional playback quality on your PC. FxSound Enhancer optimizes your music in seconds. It simply runs in the background. Just turn on your music and enjoy an improved listening experience.

http://www.fxsound.com/