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,
The Singing Voice of Japan The Singing Voice of Japan The singing voice of Japan (, "Nihon no Utagoe" / うたごえ運動, "Utagoe-undō") is the name of a social and political movement that emerged after World War II in Japan and based on musical and choral activities of the working class of the entire nation. On the ideological position of communism or democratic socialism, activists of the movement organize choral circles in factories, in schools and in their residential areas. The movement reached its peak in the years 1950–60. Japanese singer Akiko Seki () is generally regarded as the founder of the Singing Voice of Japan.