From Blaze Audio:
WebEQ XP is a real-time 10 band graphic equalizer for your computer - it optimizes your PC's sound system so that your computer's audio can achieve the highest quality sound. It's inexpensive, easy to use, and, with the right speakers or headphones, delivers fidelity comparable to your car or home stereo. With WebEQ XP, you choose Bass Boost or Equalizer, or apply three, five, seven, or ten full bands of equalization. It works in Real-time while your computer plays. Select the exact qualities you want for different types of music and then put them on one of the 6 Preset buttons. A simple click is all you'll need and the sound is automatically adjusted so the quality of streaming audio remains perfect. A full graphic display shows you how much energy there is in each band, so you can tell if you need to adjust the sliders. WebEQ XP is easy to install, easy to use, and can save you hundreds over a new stereo system or external hardware equalizer.