When all the tracks have been processed, they can finally be mixed. The typical problems you might face when mixing include:
Getting all the tracks at a volume where they can be heard without standing apart too much. Good balance is usually desired, and this is easily recognized by a trained ear. Sometimes, it might be favorable to lift a track above the balance; pushing it out in front of the mix. This is often done by automating the volume of the track so it stands out when desired, but remains discreet at other times. Volume automation can sometimes be the bulk of a mixer’s work!
Pan staging is the next issue, and this often gets played back and forth with volume adjustments. Panning a track off of center, brings the track out of the mix in more than one way. It makes the track louder in the speaker where it’s panned, and it sets the track apart from others by way of direction sense. Two things that can help with setting up a panorama of your mix are separating instruments with similar frequencies, and using pan separation tools to align each track’s direction with an appropriate sense of width for its perceived depth in a three dimensional space. Both of these techniques are worth taking the time to learn.
Further equalization is often necessary to get rid of frequency masking. When two tracks share the same frequencies, they can interfere with one another and muddy up both individual tracks as a consequence. Creating tasteful differences between them with an equalizer can be a great boon to your mix. The best place to hear where this phenomenon takes place, is in mono. With left and right summed together, the tracks can be heard on top of one another. Alternately, listening to each side of the mix separately can be a way of checking the result in stereo.
A mix also has to be congealed in the mix bus. This is where much of the personal technique of each mix engineer comes into play. Through the use of mix bus compression, stereo equalization, and many other effects, a mix can take on a personality. The use of aux sends and returns are sometimes favorable; and almost always, it helps to subgroup your tracks. For instance, all drums into one stereo bus with everything panned the way you want, so further processing can be done on the drums together. Another style is to subgroup the tracks according to the timeline of the song; creating what’s commonly referred to as stems. Stems can be thought of as separate mixes made on the same mixing board. This gives a very different feel to each part of the song and might be just what the mix needs to develop over the course of the song. However you choose to mix, be sure to watch your volume levels for clipping and if needed, use limiters on the tracks that sit too close to the top. Some trimming of the overall volume of your mix is necessary to get a mix from start to finish.
Lastly, is headroom; very big deal and often overlooked! In order for a mix to sound loud and clear, or anything close to professional, unnecessary frequencies have to be trimmed out of the mix. Much of what needs to be omitted is on the bottom end. Lower frequencies below the 50 hz mark are ok in a mix but don’t have to come from every single track. The instruments that reside in those frequencies should be the main ones heard there. Using high pass filters on the tracks that don’t belong there, can go a long way toward cleaning up the mix and bringing out those lower instruments, like bass and kick. Don’t just stop there; do the same on the high end by using low pass filters to sculpt out the higher frequencies from the lower instruments which may not need to be heard so loudly. Tracks that sit in the middle of the EQ band, like vocals or acoustic instruments can be a little trickier. Take away either or both ends as needed but be sure to listen to both soloed and mixed, to be certain the overall tone is good. A bell filter or step filter might be perfect for this kind of work.