Audio mixing is the process of taking all of the individually recorded tracks and blending / balancing the volumes and frequencies to create a coherent and pleasing piece of audio.
Some of the things done during mixing are:
- Balancing relative audio levels
- Spatial positioning (the placement of a sound within a stereo or surround field)
- Equalization (affecting the relative frequency balance to help keep tracks from competing with each other so that they sound clear and work together as a whole)
- Dynamics processing (controlling the volume dynamics of tracks so that they fit better within the over all mix)
- Effects processing(adding reverb, delay and/or other effects creating depth and space to tracks and the overall mix)
- Sample blending to make drums and other instruments sound bigger and cut threw the mix better.
Mixing is a very important step in creating the final result and an appropriate amount of time should be spent mixing. As with the recording process, mixing time depends on several factors including: the length of the piece of audio, the number of parts involved and the complexity of the material. A very basic mix of a single vocal line and backing track may only take an hour but a more complex mix of many tracks can take eight or more hours. Generally, for a basic 3-4 minute rock/pop song at least 3 hours of mixing is required.