Voice classification in non-classical music the muscular, aerodynamic, and acoustical conditions in the larynx and in the vocal tract. The subglottal pressure, the driving force in phonation, needs to be adapted in accordance with the laryngeal conditions.” In other words, the very act of singing consistently within one technique or another literally causes the voice to physically develop in different ways, and thus change the timbre of that particular voice. Another example would be a coloratura soprano in opera. This is not only the highest female voice in opera, but also distinguished by its ability to do vocal acrobatic leaps, fast vocal runs and trills,
Singing opera singing method, where chest voice was identified as the lowest and head voice the highest of three vocal registers: the chest, passagio, and head registers. This approach is still taught by some vocal pedagogists today. Another current popular approach that is based on the bel canto model is to divide both men and women's voices into three registers. Men's voices are divided into "chest register", "head register", and "falsetto register" and woman's voices into "chest register", "middle register", and "head register". Such pedagogists teach that the head register is a vocal technique used in singing to describe the resonance