For the Fred Frith album, see Guitar Solos. This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2006) In popular music, a guitar solo is a melodic passage, section, or entire piece of music written for an electric guitar or an acoustic guitar. Guitar solos, which often contain varying degrees of improvisation, are used in many styles of popular music such as blues, swing, jazz, jazz fusion, rock and metal. Guitar solos are also used in classical music forms such as chamber music and concertos. Guitar solos range from unaccompanied works for a single guitar to compositions with accompaniment from other instruments. The accompaniment musicians for a guitar solo can range from a small ensemble such as a jazz quartet or a rock band, to a large ensemble such as an orchestra or big band. Unaccompanied acoustic guitar music is found in folk and classical music dating as far back as the instrument has existed, and the use of an acoustic guitar as a solo voice within an ensemble dates back at least to the Baroque concerto. Rock music: Even though guitar solos are used in a wide range of genres, the term guitar solo often refers specifically to the rock music genre. The dramatic, amplified electric guitar solo has become a characteristic part of rock music. Since the 1960s, electric guitarists have often altered the timbre of their guitar adding electronic guitar effects such as reverb, distortion, delay, and chorus to make the sound fuller and add harmonic overtones. Rock bands often have two guitarists, designated "lead" and "rhythm", with the "lead" player performing the solos while the "rhythm" player accompanies with chords or riffs. Most examples of rock music are based around songs in very traditional forms. The main formal features are therefore verses, choruses, and bridges. The guitar solo is usually the most significant instrumental section of a mainstream rock song. In other rock-related genres, such as pop and dance music, the synthesizer usually plays this role. This use of a guitar instrumental interlude in rock music has its roots in blues musicians such as John Lee Hooker, Muddy Waters and T-Bone Walker. Ernest Tubb's 1940 honky tonk classic, "Walking the Floor over You" was the first "hit" recording to feature and highlight a solo by a standard electric guitar-though earlier hits featured electric lap steel guitars. Blues master Lonnie Johnson had also recorded at least one on electric guitar, but his innovation was neither much noted nor influential. These pioneers in turn influenced solos in rhythm and blues (e.g., Bo Diddley), rock and roll (e.g. Chuck Berry) and more recent forms of music. In a lot of cases,when compared to the length of the whole song, the rock guitar solo is a comparatively short instrumental section,which often is 20-39 seconds long. In the classic verse-chorus form, it often falls between the second chorus and third verse. Sometimes the guitar solos are extended up to such durations as 2-3 minutes or even more. An example of such extension is the album version of "Sweet Child O' Mine" by Guns'N'Roses. Sometimes extended guitar solos are used as a song's outro, such as Radiohead's "Paranoid Android", Lynyrd Skynyrd's "Free Bird", Pink Floyd's "Comfortably Numb", Guns N' Roses' "November Rain", Metallica's "Fade to Black", Led Zeppelin's "Black Dog", The Beatles' "While My Guitar Gently Weeps", The Rolling Stones' "Sympathy for the Devil", Pearl Jam's "Alive", Red Hot Chili Peppers' "Dani California", Cream's "White Room", AC/DC's "Let There Be Rock", Outlaws' "Green Grass and High Tides", The Alan Parsons Project's "Eye in the Sky" and Eagles' "Hotel California". Solos can take place in the intro, such as "Voodoo Child (Slight Return)" by Jimi Hendrix, "Since I've Been Loving You" by Led Zeppelin, "One" and "No Remorse" by Metallica, "Lazy" by Deep Purple, "I Want It All" by Queen, "Johnny B. Goode" by Chuck Berry, "Don't Take Me Alive" by Steely Dan, "Raised on Rock" by the Scorpions and "Wish You Were Here" by Pink Floyd. The use of guitar solos in heavy metal was notable during the 1980s, when rapid-fire "shredding" solos were common; a virtuostic lead guitarist of a band might be more well-known than the singer. During this time the use of techniques such as harmonics became more widely used. Later, guitarists who had developed considerable technical facility began to release albums which consisted only of guitar compositions. Guitar solos in popular music went out of fashion in the middle 1990s, coinciding with the rise in popularity of nu metal and grunge. Nu metal differed significantly from previous subgenres of metal and abandoned guitar solos altogether, except for a few rare lead fills here and there, whilst grunge did not wholly abandon solos and included them from time to time. Guitar solos likewise became less prominent in many pop and popular rock music styles; either being trimmed down to a short four-bar transition or omitted entirely, in a vast departure from the heavy usage of solos in classic rock music from the 1960s, 1970s, 1980s, and early 1990s. Classic rock revival music heavily features soloing, along with classic rock bands that are still active, as of 2012. Occasionally, there will be a two-part guitar solo with both the rhythm and lead guitar taking solos: (e.g. "Master of Puppets" by Metallica), or dual solos with both lead and rhythm playing complementary solos such as with Twisted Sister's "30", Iron Maiden's Hallowed Be Thy Name, The Trooper and Metallica's "The Four Horsemen", or Megadeth's "Mechanix". Bass guitar solos: While bass guitar solos are not common in popular music, some bands also include bass solos in some songs, particularly heavy metal, funk, and progressive rock bands. Some genres use bass guitar solos in most songs, such as jazz bands or jazz fusion groups. Bass solos are also common in certain styles of punk music. In a rock context, bass guitar solos are structured and performed in a similar fashion as rock guitar solos, often with the musical accompaniment from the verse or chorus sections. While bass guitar solos appear on few studio albums from rock or pop bands, genres such as progressive rock, fusion-influenced rock, and some types of heavy metal are more likely to include bass solos, both in studio albums and in live performances. Bass solos are performed using a range of different techniques, such as plucking or fingerpicking. In the 1960s, The Who's bassist, John Entwistle, performed a bass break on the song "My Generation" using a plectrum, though he intended to use his fingers. This is considered by many as one of the first bass solos in rock music, and also one of the most recognizable. John Paul Jones of Led Zeppelin, on "Good Times Bad Times", the first song on their first album, uses two bass solos in an influentially dynamic way, as a bridge (when the band drops out after the choruses) to the next verse (after the first chorus) and the guitar solo-driven coda (after the third chorus). Queen's bassist, John Deacon, occasionally played bass solos, notably in "Under Pressure" or "Liar". In the 1970s, Aerosmith's bassist, Tom Hamilton, played a bass intro on the song "Sweet Emotion" from their album Toys in the Attic. On thrash metal group Metallica's 1983 debut Kill Em All, bassist Cliff Burton's well known solo "(Anesthesia) Pulling Teeth" is featured, and is considered his greatest work by many.John McVie of Fleetwood Mac performed a notable bass solo on "The Chain" from the 1977 record-setting Rumours album. Manowar's bassist Joey DeMaio uses special piccolo bass for his extremely fast bass solos like "Sting of the Bumblebee" and "William's Tale". Green Day bassist Mike Dirnt played a bass solo on the song "No One Knows" from the 1992 album Kerplunk!. U2 includes a bass solo most notably on "Gloria", in which Adam Clayton utilizes several playing techniques. Bassist Matt Freeman of Rancid has a very speedy, guitar-like bass solo in the song "Maxwell Murder". Heavy metal bass players such as Geezer Butler (Black Sabbath), Alex Webster (Cannibal Corpse), Cliff Burton (Metallica), jazz fusion bassist Jaco Pastorius (Weather Report), and Les Claypool (Primus, Blind Illusion) used chime-like harmonics and rapid plucking techniques in their bass solos. Geddy Lee of Rush performed a number of solos, most notably in "YYZ". Also, in both published Van Halen concert videos, Michael Anthony performs unique maneuvers and actions during his solos. Funk bassists such as Larry Graham began using slapping and popping techniques for their bass solos, which coupled a percussive thumb-slapping technique of the lower strings with an aggressive finger-snap of the higher strings, often in rhythmic alternation. The slapping and popping technique incorporates a large number of muted (or 'ghost' tones) to normal notes to add to the rhythmic effect. Slapping and popping solos were prominent in 1980s pop and R&B, and they are still used by some 2000s-era funk and Latin bands. When playing bass solos, hard rock and heavy metal bassists sometimes use bass effects such as distortion or wah-wah pedals to produce a more pronounced sound. Notably, Cliff Burton of Metallica used both distortion and wah-wah. Due to the lower range of the bass, bass guitar solos usually have a much lighter accompaniment than solos for other instruments. In some cases, the bass guitar solo is unaccompanied, or accompanied only by the drums.