Audio Enhancing Programs
DFX Audio Enhancer for the PC
Click here to download this free program. The review on the download site, Download.com, states that the program is a Winamp plug-in, but the program actually enhances all audio playing on your pc. Also, make sure to click "Decline" in the bottom left of the installation windows to avoid downloading the superfluous add-on programs.
Audio Enhancers for the Mac
Click here to see the Mac alternatives to DFX Audio Enhancer. These programs may cost money and have not been tested by me. If you know of a good free audio enhancer for the Mac, please send an email about it to meherbabamusic@gmail.com.