This all begins with a fully-formed song, with melodic material, counter-melodies, choruses, refrains, bridges, etc.. Our task with orchestration is to figure out which instruments to utilize, and how. If the song already has a standard artist or band performing it, we may be writing only background accompaniments. Alternatively, the project may call for a setting of the work for all voices/instruments. In order to achieve this, the orchestrator must understand what every instrument is capable of doing, including range, tessitura, muting, techniques, etc.. They must also know which instruments work well with each other. Add to this the vast palette of colors and sounds available from mixtures of instruments, and we now have a plethora of important facets to consider. Orchestration also requires a depth and breadth of knowledge with regard to various styles and genres of music. How would Mahler handle a passage differently from Bach, and what the merits to each approach? What orchestrational choices simply would not be feasible (i.e. pizzicato strings behind a heavy metal band)?