Princeton University cites that vocal music is intended to be performed by one or more singers, typically with a sort of instrumental background. They contrast this definition with that of instrumental music, which is melodic in its own right, but whose melody is enhanced by vocals that are responsible for carrying the tune. The ardictionary.com definition for musical vocals suggests that vocal music is more of a technique, a process where the singer expresses vocals in a singing voice as opposed to a speaking voice.
Some of the earliest vocal sheet music records date back to Ancient Greece. According to William A. Johnson of the University of Cincinnati, Greek vocal music notations have been discovered on early AD papyrus scripts. Other ancient vocal music originated with the Psalms of King David, which he often played on a harp. Since these periods, the world has heard the vocal chant music of the Middle Ages which led to polyphony, where composers found they could orchestrate more than one melody line in a song. Later forms of vocal music in the classical, romantic and modern periods brought the development of instrumental accompaniment, stronger poetic structure and non-operatic melody styles.
There are as many types of vocal music as there are music genres. For each musical classification, including period music, sacred hymns, pop, rock, jazz, country, opera and Broadway musicals, there is a corresponding vocal style that fits with the beat, feeling and purpose of the music. A capella vocals, however, are sung without musical accompaniment and sometimes utilize solo or duet parts to sing the melody and employ backup singers to provide harmony and rhythm.
Vocal music is laid out on sheet music with staffs for the treble clef (higher notes) and bass clef (lower notes). Sometimes the vocal line is written above the musical accompaniment, while other times, singers are given a lead sheet with only the melody line and lyrics from which to draw references.
There are many different vocal music classifications for the various vocal registers. The voice type determines the range in which a singer can comfortably perform a song. Male voice type include the lowest register, bass, followed by the baritone and tenor ranges. Female voice types consist of the low contralto and alto tones while mezzo-soprano, soprano, and coloratura make up the high ranges. Singers must choose their vocal music based on the register in which they can sing without difficulty.