The track is an organizational unit in edited audio. In the most basic sense, it’s a pathway for a voice or instrument inside your audio workstation. But each track can be given its own set of effects and its own spot in the right-left spectrum (pan), so two could also house the same source instrument or voice and still create different pathways. I like to think of tracks like train tracks, as holding sounds that move through time together. Sometimes there is no neighboring train, sometimes they run in cluster.
Tracks give you a chance to think about center and periphery. You could make a wall of sound or you could make something that sounds like a quartet of distinct but blending voices. This felting up or separating out is largely a function of making space in two dimensions: first, the one controlled by EQ, the frequency range — so that one track might find its fullness in the lower range and have suppressed high range, and another track its inverse: they don’t occupy the same frequencies (I remember once I had an air conditioner that perfectly cancelled certain frequencies in a record of mine); second, the stereo range controlled by panning, the right-left spectrum. Even nudging one track slightly off center to the right and the other slightly off center to the left will produce a clarity that is missing when they are both equally on center.
There are hygiene considerations to tracking: things like arranging them in an intuitive order and grouping them for clarity — so if I have three vocal tracks combining to make a harmony, and then a few tracks with sampled sounds, I will put my three vocal tracks next to each other. (I also like to color-code.) If you’re using a lot of samples or elements that show up only once, it’s useful to group them on one or a few tracks, so as not to have a piece with a sprawl of tracks.
But I want to pause on track thinking as a compositional affordance. If you think of time as the warp, then your tracks hold the weave yarns. There is a possibility for real alignment of aim between the material on one track and the material on another (a union controlled by harmony or by a beat, say); the possibility for a dialogue (an alternation of sound and silence so that a conversation takes place between tracks); but also a possibility for independence (emergence of a new sound in a new rhythm). There is possibility for a system of subordination (lead vocals and backing vocals), but also possibility of a meeting place between elements, an alterity between elements. If you’re stuck while you’re editing, perhaps ask yourself what a new track, housing a new sound, might offer to the composition.
(For extra credit, transpose track thinking to a writing assignment for several voices, playing with alignment, dialogue, and independence, with subordination and equal alterity.)