Upper voice
The highest voice in a texture.
What it means
The upper voice is the highest voice of a polyphonic texture. In choral music that is the soprano, in the string quartet the first violin, in four-part piano writing the topmost line. In many kinds of texture it carries the melody, because the ear follows the outer voices — the highest and the lowest — most clearly. Older designations such as discantus or cantus mean the same voice within the texture.
Musical use
The preference for the upper voice as the carrier of the melody becomes established from the sixteenth century onward; in older polyphony the given melody often lay in the tenor. With the figured bass, the layout arises in which upper voice and bass form the frame and the middle voices fill it in — a structure that shapes the music of the following centuries. For compositional technique it follows that errors in the outer voices stand out most strongly and that their leading demands particular care. Composers play with this expectation by temporarily shifting the melody into a middle voice or into the bass.
Performance practice
Take care to let the upper voice stand out tonally without forcing it; on the piano this happens through a little more weight in the fifth finger, in ensemble through agreement on balance. At the same time, check whether the melody lies elsewhere at certain points, and adjust the weighting. In choir it holds: the soprano leads, but intonation is guided by the bass. Practise pieces also so that you deliberately make a middle voice audible — this sharpens the ear for the whole texture.
Bear in mind that the melody does not always lie on top: in older music the tenor often carries the given line, and later composers too shift the main voice into middle voices or into the bass. Check this for every section before fixing the weighting. On the piano, the upper voice's prominence arises through a little more weight in the outer finger, in ensemble through agreement. On the piano, play the upper voice with a little more weight than the accompaniment, especially in chorale settings.