After recording your song, you sit for many hours with your mix engineer
and take painstaking effort to make sure your mix is in its most perfect form possible. After hearing the mix many many times, your ears begin to get used to the way it sounds, which causes you and/or the mix engineer to lose perspective. You then go and compare it to commercial releases and realize you mix simply is not up to par. This is where mastering comes into play.
The cost of hiring an audio mastering engineer
was always one of the most expensive parts of a music project. Now that it can be done online, it allows for way more people to get great sounding music out of their mixes. Online mastering has become much more popular lately, as qualified and creative engineers are providing their services via the internet. Click here for online mastering samples.