A
pinch harmonic or
pick harmonic[1] is a
guitar technique pioneered by
Roy Buchanan on the 1962 recording of "Potato Peeler"
[2] in which the player's thumb or index finger on the picking hand, slightly catches the string after it is picked, canceling the
fundamental of the string, and letting one of the
overtones to dominate in a similar way to how
altissimo notes are produced on
woodwind instruments. This results in a high
pitched sound. By using string bending, a
whammy bar, a
wah-wah pedal, or other effects,
electric guitarists are able to modulate the pitch, frequency, and
timbre of pinch harmonics, resulting in a variety of sounds, the most common being a very high-pitched squeal.
The technique is possible on any fretted stringed instrument, but is most widely employed by electric guitarists, especially in heavy metal and rock music where heavy distortion ensures that the otherwise subtle harmonic is greatly amplified. One of the earliest guitarists to frequently use pinched harmonics in his playing was Leslie West of Mountain, active during the early 1970s. But it was artists such as Eddie Van Halen, Dimebag Darrell and Steve Vai who made the technique popular, utilizing the tremolo arm and high gain amps together with the pinch harmonic. This ended up producing wild, screaming, horse-like wails from the instrument. Steve Vai composed a track named "Bad Horsie," that uses heavy pinch harmonic techniques. A pinch harmonic was used at the beginning of the second solo of Pink Floyd's famous Comfortably Numb of 1979.
Pinch harmonics are used extensively in death metal. The technique's use in death metal is notable in that pinch harmonic notes are included in riffs, rather than being reserved for solos. Combined with the rather low tunings most of these guitarists use, and the fact that they are usually played by both rhythm guitarists (if there are two), the pinch harmonic notes leap out, creating more complex and twisted melodic contours than otherwise possible. The technique is also used commonly in other sub-genres of heavy metal, particularly by guitarists such as Steve Morse, Glenn Tipton, Zakk Wylde, Richie Sambora and Dimebag Darrell. One guitarist of the rock genre who is widely known for his use of pinch harmonics is Billy Gibbons of ZZ Top, who uses them frequently in guitar solos, an excellent example being the second solo on the well known ZZ Top track "La Grange". Another superb exponent of this technique was the late great Irish Blues/Rock guitarist Rory Gallagher, check out the soloing on the track "Walk On Hot Coals" from the album "Irish Tour '74". There are also other types of harmonics such as natural harmonics and tapped harmonics.
A pinch harmonic is produced when the thumb of the picking hand lightly touches against the string immediately after it is picked. This action is sufficient to silence the fundamental and all overtones except those that have a node at that location. This is generally accomplished by holding the guitar pick so that very little of its tip protrudes between the thumb and forefinger (roughly 3–5&_160;mm), allowing the thumb to brush the string immediately after it is picked.
