Steven Siro Vai (born June 6, 1960) is an American guitarist, songwriter and producer who has sold over 15 million albums. He and his contemporary Joe Satriani are widely regarded as virtuosos on their instruments with their skill extending beyond their affinity for their instrument to their mastery of the technology necessary to present their art to the public. After starting his career as a music transcriptionist for Frank Zappa, Vai recorded and toured in Zappa's band for two years, from 1980 to 1982. He began a solo career in 1983, has released eight solo albums and won three Grammy Awards. He has also recorded and toured with Public Image Ltd., Alcatrazz, David Lee Roth and Whitesnake. Vai has been a regular touring member of the G3 Concert Tour which began in 1995. In 1999, Vai started his own record label Favored Nations, intending to showcase as he describes, "... artists that have attained the highest performance level on their chosen instruments."

Steve Vai has been called a guitar virtuoso. His 1990 album Passion and Warfare is often cited by critics and fans alike as among his best works. Particularly the instrumental "For the Love of God" has received a lot of attention from the music press, and is noteworthy in that the entire six-minute piece was reportedly recorded in just one take. Vai's playing style has been characterized as quirky and angular, due to his technical ability with the guitar instrument and deep knowledge of music theory. He regularly uses odd rhythmic groupings and his melodies often employ the Lydian mode.

Perhaps his most readily-identifiable stylistic feature is his creative use of the floating vibrato, using it to add melodic lines that sound odd to the ear. His playing can be described as lyrical, as if sung by a human voice. During the recording of "Eat 'em and Smile" with David Lee Roth, he employed several guitar techniques that "mimicked" the human voice, as heard in the opening bars of the opening track "Yankee Rose." He is noted for being physically expressive as he plays his guitar. He often uses exotic guitars: he plays both double and triple neck guitars.

Vai is also a producer. He owns two studios, "The Mothership" and "The Harmony Hut", and his own recordings combine his guitar skills and novel compositions with studio and recording effects. Vai helped design his signature Ibanez JEM guitar series. They feature a hand grip (fondly referred to as a "monkey grip") cut into the top of the body of the guitar, a humbucker–single coil-humbucker (H/S/H) DiMarzio pickup configuration with several different types of pickup including Evolution, Breed and EVO 2. He also uses the Ibanez Edge and Lo-Pro Edge double-locking tremolo systems (between the years 2003-2009, production JEMs had the Edge Pro, which is now discontinued), as well as an elaborate and extensive "Tree of Life" inlay down the neck. Vai also equips many of his guitars with an Ibanez Backstop, a tremolo stabilizer that has been discontinued. Lately Vai has also equipped some of his guitars with True Temperament fretboards to make his chords sound more in tune.

Vai has a 7-string model designed by him named Ibanez Universe, featuring DiMarzio Blaze pickups in an HSH arrangement. The Universe gained additional early attention in the early-to-mid '90s from two bands/musicians other than Vai: Korn, who used the guitar downtuned an additional step (to "A"), selling millions of albums worldwide and pioneered nu metal songwriting and sonics with their uniquely heavy yet untraditionally "Heavy Metal" sounds, as well as Progressive Rock band Dream Theater whose guitarist John Petrucci began using Ibanez 7-strings on their 1994 album Awake and has continued to do so in their technically challenging playing and songwriting. Vai also has a signature Ibanez acoustic, the Euphoria. His two main guitars are white JEMs dubbed "Evo" and "Flo", each with their own unique modifications. Before Ibanez, he briefly endorsed Jackson guitars, but the relationship only lasted two years. Steve Vai has also worked with Carvin Guitars and Pro Audio to develop the Carvin Legacy line of guitar amplifiers. Vai wanted to create an affordable amp that was unique, and equal in sound and versatility to any guitar amp he had previously used. Over his long musical career, Steve Vai has used and designed an array of guitars. He even had his blood put into the swirl paint job on one of his signature JEM guitars, the JEM2KDNA. Only 300 of these were made. Currently, he mainly uses his white "Evo", a JEM7V, and his "Flo", which is a customized Floral JEM 77FP painted white. They are both inscribed with their names in two places, mainly so he can distinguish between them onstage. "Flo" is equipped with a Fernandes sustainer system.

He has a guitar named "Mojo" with dot inlays that are blue LED lights. He has a custom-made triple-neck guitar that has the same basic features as his JEM7V guitars. The top neck is a 12-string guitar, the middle is a six-string, and the bottom is a six-string fretless guitar with a Fernandes Sustainer pickup. This guitar was featured on the G3 2003 tour on the piece I Know You're Here. Vai's effects pedals include a modified Boss DS-1, Ibanez Tube Screamer, Morley Bad Horsie, Ibanez Jemini Twin Distortion Pedal, TC Electronics G-System, Morley Little Alligator Volume pedal, DigiTech Whammy, and an MXR Phase 90/Phase 100 on the Passion and Warfare album. His flight cases are labeled "Mr. Vai", or lately, "Dr. Vai." He has used a number of rack effects units controlled via MIDI, but used a floor-based TC electronics G system instead for the Zappa Plays Zappa tour.

Source : http://en.wikipedia.org/wiki/Steve_Vai