Basic Mastering Techniques
Basic mastering involves the changing of the sound wave using normalization, top and tailing, master equalization and loudness maximization.
Basic mastering will help give a finished mix more of a commercial finish. It's worth noting that mastering can be an extremely complex subject and can take years to become proficient in.
Normalization is the process of increasing the average or peak amplitude amount of gain of a waveform to 0dB i.e the maximum sample value that a digital signal can achieve.
Normalization ensures that all subsequent processes are carried out at the maximum achievable resolution.
Top and Tailing
Top and tailing is the process of trimming the beginning and end of the sound file so that it starts and end immediately without silence.
Adding some equalization tweaks can make the difference between a good track and a great track. Check out the sounds frequency output to see if there are any unnecessary peaks and troughs and adjust accordingly.
If creating an album, it's important that all songs have the same subjective quality so should be equalized together.
In order to make the track louder and give it more punch, it's important to apply loudness maximization (compression and limiting) to bring the overall RMS up.
The perceived volume of a song lies in its RMS (average) power and not its peak to peak power.
It's worth noting that not all music needs loudness maximization. For example classical music has a large dynamic range which is desired to be kept.
Prior to loudness maximization, a waveform is fairly uneven. After the wave looks more even, with the dynamic range reduced.
To achieve an even louder sound, it is possible to add multi-band compression, which uses different amounts of compression for different frequency bands.
There are many plugins and software packages that allow you to maximize the loudness using a couple of simple controls. Usually there is a threshold and output ceiling. While the threshold is lowered the volume of the song will increase. The output ceiling is usually set to 0dB or just under. If the threshold position is lowered too much, distortion will become apparent. It's all about finding the sweet spot; a decent increase in loudness without distortion.