Navigate your browser to the SoundMAX Audio Driver Download site (see Resources).
Scroll through the options and choose the download that best suits your PC (e.g., choose the Windows Vista option if you have Windows Vista). Click the country you're living in to begin the download.
Unzip the file after it's finished downloading and run the setup.exe file. Install the program.
Open the SoundMAX Digital Audio software. A "Stereo Mix" option should now be available. It's in the bottom right corner of the software window. Move it up or down to increase the output volume of your audio playback.