Vocals are one of four instruments available to player which debuted in Guitar Hero World Tour, and has been included in every Guitar Hero game since. To sing one must obviously have a microphone compatible with the system the player plays on.
The object of vocals differs from the other three instruments. Instead of notes, a tunnel will appear with the lyrics of the song underneath. With vocals the singer is to try to keep the comet inside the tunnel as much as possible. With each difficulty more correct pitch is needed to obtain an excellent rating which would score more points, and raise/maintain a 4x multiplier. When singing the comet will leave an orange trail inside to show how well the singing was. In GH: World Tour the only rating the player would get was a colored flash which would appear upon finishing a phrase. From GHM on, the player would receive ratings for the quality of the singing. In GH5, Band Hero, and GH WOR the new highway has a different rating system. Located next to the rock meter there is a small bar. While singing the bar will fill will color. The color varies from white to yellow to green. Also the amount of points attained depends on the size of the phrase and how much the tunnel was filled.
With singing, pitch, and timing are factors that the player must possess, rather than enunciation. The only exception to pitch, are spoken notes. Spoken notes are notes which are either fast pitched, screamed, or rapped. These can be sung at any pitch, as long as they are sung. On beginner difficulty all phrases in a song have only spoken notes. In GH5, and Band Hero spoken notes are notes that are bigger than normal notes and are located at the middle of the highway. In GHWOR they are at the bottom of the highway, and not in a tunnel.
Star Power can be gained in different ways. One way is available only in pre-GH5 games & GH5 and BH in PS2. Obtaining "solid" or "excellent" ratings on any phrase will give the player star power. Secondly is by singing into a hype. Hypes are sections of a song which appear as blue clapping hands. Singing into these will also boost the rock meter.
In GH5 and later games there are only two ways to obtain star power. One way is obtaining an excellent rating on a star power phase. Star power phases are blue instead of yellow and only appear on certain phrases of the song. Secondly is by gaining star power through star power overload in band play. Also to activate a band moment, the vocalist must get an excellent rating on any phrase in which the band moment is present.
Star power can be activated by blowing a rush of air into the mic or by pressing a button on the controller.
Another part of vocals are freeforms. These appear as wavy sections of the song. While in one of these the player can earn bonus points by matching the pitch of the song. Each song will have a different pitch for freeforms, and a different octave which these are sung in. The better the singing is, the more points are gained, as well as a multiplier which is increased with better singing. Star power can also be used to multiply the freeform score.
Freeforms in GH5, and GH WOR no longer grant the player points. The only purpose of these is to boost the rock meter.
Depending on how well a phrase was sung, the player will receive ratings, and a base amount of points. These are the ratings and scores found in the GH: World Tour games.
In GH: World Tour, GH: Metallica, GH: Van Halen, and GH: Smash Hits there are two types of vocal style: static and scrolling. With static vocals the comet is moving while the pitch guides are still. And in scrolling the comet is still while the pitch guides are moving. In Guitar Hero: 5, Band Hero, and Guitar Hero: Warriors there is a new vocal style known as karaoke. With karaoke the lyrics take up the screen and the player must rely on prior knowledge of the pitch rather than a pitch guide. Also lyrics that are white are yet to be sung and lyrics which are blue have already been sung.