Seven and eight string guitars are quite a staple in today's metal music, being used by bands like Meshuggah, Fear Factory, Scar Symetry, Periphery and many others. From progressive, rhythmic and technically challenging pieces to unashamed down tuned brutality, these guitars seem to have been carved to cater for the heavy riff hungry hordes of the heavier side of rock ever since Steve Vai's Universe first appeared on the scene. Their true origin and applications, however, go far beyond such a restrictive set of musical genres.
As music became more complex in the Baroque period, many guitarists lusted for more range in the instrument, which would enable them to write and perform music that would encompass a broader spectrum in the sonic landscape. The humble 5-course guitar, while vastly used in many forms of popular music, was not keeping up with the demands of music at the time, and its range had to be extended, and the first incarnations of the ubiquitous classical guitar appeared in the 1700's, first in 12 strings forming 6 courses, and evolving to the popular 6-string format, tuned in a variety of ways depending on the pieces themselves and which instrument they had been written for (playing lute pieces on the guitar was one of the driving forces behind the extra course) . In parallel with the universally popular 6-string, however, multiple course instruments appeared, aiming to provide the musicians with more usable range - and a more encompassing approach when it came to the sound spectrum; the first of these instruments to become popular was none other than the seven-string guitar.
The birth and popularization of the seven-string guitar
The first examples of seven-string guitars as a fully fledged instrument take us on a trip to the 18th Century, when electricity, let alone the electric guitar, was still far from being more than a mere academic curiosity. A Mexican composer named Antonio Vargas left us a variety of pieces written specifically for the "guitarra sétima" (which literally translates to seventh guitar, a 14-string, 7-course instrument) in the last quarter of the century, and there is documental evidence of 7-string guitars used to be able to attain the range of the then dominant lute.
An interesting fact is that the now standard six-string guitar didn't become truly the norm until the early 1800's, as baroque guitars commonly had 10-strings in a 5 course layout. At the same time, however, the Russian seven-string guitar emerged and gained popularity locally, becoming an integrant part of many forms of local folk and classical music alike. The "semistrunnaya gitara" (which literally means "seven-string guitar") was usually used with fingerpicked open tunings - most frequently D G B D G B D -, and was embraced for different purposes due to its inherent versatility, which allowed complex pieces to be executed taking advantage of the guitar's extended range, and popular music alike, as the open tuning made accompaniment with alternating bass lines simple and intuitive for musicians with no formal training. The Spanish guitar (our classical guitar) was extremely rare in Russia until the revolution took place in 1917, and until the regime deemed guitar music to be mundane and a bourgeois manifestation, the seven-string guitar reigned as an important part of Russian musical culture.
In the early 1900's, Brazil saw the introduction of the seven-string guitar. The "violão de sete cordas" (it simply means seven-string guitar) had its distinctive use in Brazilian music develop throughout the century, and one name stands out as the prime developer and proponent of the "baixaria" (a term used to jokingly describe the prevalent bass lines) in the Choro style: Dino 7 Cordas (seven string Dino), as he was known, was responsible for an incredibly extensive repertoire which put to use the added range of the instrument. Dino played with many of the greats in the Brazilian music scene, which further bolstered the popularity of the seven-string guitar. In Choro songs, it is quite common to have the seven-string guitar holding the rhythm and complementing the melody and one or more tenor instruments (such as the cavaquinho, cavaco or mandolin) delivering the main melody for the song.
The arrival to the electric guitar world
Contrary to many tales, Steve Vai didn't truly introduce the 7-string to the electric guitar world, nor do Alex Gregory's infamous claims of "inventing" the seven-string guitar (even in its electric incarnation), as both men were preceded by another guitarist who, before they were born, commissioned an electric version of the instrument, and his busy schedule brought the instrument to the public in a context that is as detached from heavy metal as possible: this man was George Van Eps, a popular American jazz guitarist, who ordered this unseen at the time example from Epiphone in the late 1930's. George gained notoriety and his distinctive approach tuning the 7th string to low A allowed him to play walking bass lines at the same time as melody parts, and to spread chordal work across several octaves with no dramatic position shifts. In 1968, this prolific composer, session musician and teacher closed a deal with Gretsch Guitars, one that would originate the first true seven-string signature model, and the first production 7-string electric.
In 1982, what appears to be the first solid-body seven-string electric was built by the luthier Kirk Sand for Lenny Breau, and debuted at NAMM in 1983. A more massified approach was attempted in 1987 by Fender in collaboration with Alex Gregory, but the partnership produced only a few prototypes and the actual production models never materialized. The first mass-produced solid body seven-string was Steve Vai's Universe, and the model entered production in 1990. This guitar features a low B to follow the guitar's standard 4ths tuning took place instead. Steve Vai is seen holding two different Universe guitars in the cover and booklet of his acclaimed album Passion and Warfare, and earlier examples of the multicolored swirl pattern UV777MC command high values in the secondary market. The Universe is in production to this day and remains a successful product in the Ibanez line, having been used by other prominent rock and metal artists like John Petrucci and Trey Azagthoth during the 90's.
The 21st century and the 7-string - the rise to fame
While the Universe was used by well known and loved virtuoso players, both guitarists in a band that would single-handedly define a trend for years to come used their own Universe guitars to do something different than the then usual low tuned riffs and technically demanding solos: this duo of innovative players preferred to detune the instrument to drop A like ts original electric incarnation's, but the idea was to combine immensely powerful riffs with percussive noises and squeals one would easily associate to hip hop back then. These two players were Brian Welch and James Shaffer, also known as Head and Munky, and their band Korn's self-titled debut album marked the beginning of what would be known as nu-metal: a powerful mix of metal, hip hop and experimental textures using the guitar as their source. Korn's rising popularity made many makers view the seven-string as a valid product, and it wasn't long until companies like Schecter, ESP or Brian Moore guitars had fully fledged seven-string lines in their product rosters. Not all was good for the instrument in this sudden rise to fame, though: the ever-growing stigma of the seven-string being a niche nu-metal instrument contributed to deter those not interested in the genre from taking an interest, and by the time music trends started dictating other directions that led to nu-metal's decline, seven-strings' popularity waned as well, returning it to its role of the niche instrument for players looking for added range.
The late 90's and early 2000's saw a setady increase in the instrument's popularity, more notably in metal music, where the instrument's powerful low end without sacrificing high note availability made it find its way to many players like Dino Cazares of Fear Factory fame or Fredrik Thordendal and Mårten Hagström from Meshuggah, among a horde of prominent guitarists. Meshuggah's syncopated, rhythmically complex riffing influenced many bands, who fused such elements with melodic passages, complex chords one wouldn't originally believe he'd find in metal, and bands like Periphery or Animals as Leaders show a blend of these traits, intense soundscapes and musical proficiency that creates a progressive approach that takes full advantage of the range of these instruments. Meshuggah and Animals as Leaders, as well as Fear Factory, have picked up the eight-string guitar since to use even broader range in their musical endeavors, but we shall leave that for another article.
At the present, the seven-string maintains its status as an instrument that is appreciated by many players in radically different styles and genres, and while far from overthrowing its six-string counterpart, it seems to be here to stay, capturing the interest of players due to its extended chordal and soloing possibilities, the heaviness of the lower tuning, the ability to play melody and bass lines in a single instrument or all of these combined to take advantage of the potential these guitars possess - who'd imagine a single added string could originate a guitar that stands out from its mainstream brethren in so many ways?