Most bands or music ensemble groups follow a consistent configuration. Perhaps the most common is the four-piece group composed of two guitarists, one bassist, and one drummer. One or both of the guitarists usually sing, though there are bands where the drummer or the bassist acts as the vocals. Another quite common trend is that the vocalist does not play an instrument, focusing more on getting the attention of the audience and making the performance livelier.
The lead vocalist or frontman (or frontwoman) use their voice as the main melody of the band. Though other band members join in to sing along, it is the vocalist's sound that stands out from the rest. The melody from his voice is prominent throughout the song, while the backing vocals only join in during other parts of the song, specifically in the bridge or in the chorus. One of the most famous vocalists in a band who does not play an instrument is the late Freddie Mercury from the British rock band Queen.
Also known as the solo guitar, the musician assigned with the lead guitar is usually the one who plays the main melody of the song. This includes instrumental parts, guitar solos, and some prominent riffs that typically stand out. The lead guitarist is generally found in bands with two guitarists in them, especially in rock and jazz bands. George Harrison plays most of the lead parts in The Beatles' songs.
While the lead guitarists are playing the "important" parts such as guitar solos and prominent riffs, the second guitarist (also known as rhythm guitars) comes in with the melody foundation to make the song sound more solid. In some cases where a vocalist is not present, the rhythm guitarists are the ones who also play the vocals. Examples of these vocalist-guitarists are James Hetfield from Metallica and Dave Mustaine from Megadeth. However, these two sometimes do the guitar solos of certain songs.
This position is reserved for musicians who play the low brass instrument of the song. They usually "connect" the beat and the rhythm, helping the guitars and the drums blend more smoothly. The bass lines also feature tapping, slapping, and other tricks that only the unique instrument can use. One of the most famous bassists is Michael "Flea" Balzary from Red Hot Chili Peppers.
The percussionist creates the music by beating multiple instruments called a drum kit (or drum set or trap set) with timing. The drummer determines the pace of the song, allowing the bassists and the guitarists to follow. One of the most prominent drummers is Phil Collins from the rock band Genesis. This is because he is one of the rare instances when the drummer is also the vocalist.
Keyboardist or Pianist and Other Instruments
Some bands employ other musical instruments to replace the guitars, bass, or drums. Some hire keyboardists or pianists who can usually fill in for the guitars and bass. Several bands use electronic beats instead of an actual live drummer.