Open your preferred audio production program, for example Pro Tools, Logic Pro or Adobe Audition. Double-click the desktop icon. If you don't have a desktop shortcut, select the program from the "Start" menu on a PC or "Applications" folder on Mac.
Click "File" and select "Import." Select the song you wish to master. Importing the audio opens it in the production program.
Select "Multi-band Compressor" from the "Tools" menu. The multi-band compressor creates a graphical representation of the frequency spectrum of your audio. Typically such compressors split the frequency range into four bands. Cut or boost each band by moving the assigned slider dial with your cursor. For example, to add more bass adjust the left-most slider dial upward. Play a commercially released alternative sound recording to hear which frequencies are typically enhanced in alternative music.
Increase the dominant frequencies. If your song is bass-heavy, enhance this characteristic. This is where pop and alternative mastering differs. To get a polished pop sound, you tone down rogue frequencies. If you're going for an edgy, alternative sound, enhance these rogue frequencies to bring them to the fore.
Select "Limiter" from the tools menu. The limiter tool works in a similar way to the multi-band compressor, but instead of adjusting frequencies it boosts and cuts volume levels. The purpose of limiting is to reduce the dynamic range of the sound recording to make it suitable for multiple audio applications, from night club sound systems to PC speakers. By boosting low level sound such as breaths or softly played guitars and reducing the level of loud sounds such as cymbals, you create a smaller dynamic spectrum.
Adjust the limiter parameters carefully. The limiter parameters, such as "Threshold" and "Intensity" determine how hard the limiter works. The threshold governs the base level at which the limiter kicks in. "Intensity" dictates how much boost or cut is applied. Set to extremes the limiter will "brick wall" the dynamic spectrum. This results in negligible volume difference across the audio. Listen carefully as you limit. If the subtleties in the music are becoming too obvious, reduce the parameters.