Bow control: weight not pressure (the mental model)

Tone production is the most-judged dimension at orchestral auditions and the least-taught skill in early string education. Most players are taught to press into the string for volume, which produces a thin, forced tone. The professional-level mental model is different: the bow rests on the string under its own weight, and the player's job is to direct that weight, not add to it. This is the single biggest sound-quality unlock available to most students.