Гравикорд: Электрическая арфа с двойным бриджем.

24 string, electric double bridge harp

The Gravikord is a 24 string electric double bridge harp invented by Robert Grawi in 1984, which is closely related to both the West African kora and the mbira. It was designed to employ a separated double tonal array structure making it possible to easily play cross rhythms in a polyrhythmic musical style in a modern electro acoustic instrument. The Gravi kora is a similar instrument, also developed by Grawi, which is tuned identically to a traditional 21 string kora.

The Gravikord is based on the West African kora. It is made of welded stainless steel tubing, with 24 nylon strings but no resonating gourd or skin. The bridge is made from a machined synthetic material with an integral piezo electric sensor. There are two handles located in elevation near the middle of the bridge. The bridge is curved to follow the arc of a strum from the hands which hold the shortened raised handles directly in the palms. A metal crossbar at the top of the bridge functions as a mechanical tone control and bridge stabilizer. The instrument connects to an amplifier like an electric guitar. The playing technique is similar to that of the kora: the player plucks the strings with the thumb and index finger of each hand. Because each hand can play "with" or "against" each other, simple techniques can produce music of great rhythmic complexity. However, the tuning of the Gravikord is not the same as a kora, and playing techniques are not directly compatible.

Because of the deep cultural significance of cross rhythms to sub Saharan African music, several instruments from there have been designed to more easily generate cross rhythms. Instruments such as the kora, donso ngoni, and mbira organize the notes in a uniquely divided alternate array, rather than the linear bass to treble structure common to many western instruments. On these instruments, both hands can play freely across the entire tonal range of the instrument, rather than one hand being primarily in the bass and the other in the treble. Also, the fingers of each hand can play independent rhythmic patterns, which can easily cross over from treble to bass and back, either smoothly or with varying amounts of syncopation. This can all be done within the same tight tonal range, without the left and right hand fingers ever physically encountering each other. These simple rhythms will produce complex cross rhythms including repeating on beat/off beat pattern shifts that would be very difficult to create by any other means. This characteristically African structure allows simple playing techniques to combine, producing polyrhythmic music of great beauty and complexity.

Grawi originally desired an instrument on which he could play polyrhythms more easily than on the guitar, and he refined the Gravikord's design over several years to meet this goal. The first prototype, made in 1974, was acoustic, and had a bamboo and fiberglass basket resonator with an animal skin head and a large bamboo neck. These first Gravikords already differed from the kora by having the tuning mechanisms removed from the neck and placed at the base, and an extensively re designed bridge which also incorporated a kalimba that could be played simultaneously with the strings. Their tuning also differed, as they had 25 strings that were tuned symmetrically using a variation of the Hugh Tracey kalimba tuning system. Grawi made several unique prototypes during this period using wood, aluminum, and other materials, with features including stereo output and variable pitch, and finally patented the Gravikord in 1984.

This is a new model of the Gravikord which Bob Grawi designed in collaboration with jazz musician Chief Xian aTunde Adjuah aka Christian Scott. It is a 20 stringed instrument with a taller variation of the Gravi kora's bridge resulting in wider inter string spacing, with redesigned raised handles shorter than on the Gravi kora, more like the Gravikord, allowing mid string hand positioning, and holding the instrument in a natural manner. In addition it has a third small handle welded across the lower neck as a hand rest for playing one rank of strings with both hands. Since the taller bridge is less stable it also incorporates a back stay from the top of the bridge to the tuner block.

Although both instruments are normally tuned to a diatonic scale, on slower pieces, accidentals can be created by sharping individual notes. This is accomplished by pushing and tensioning the section of the string behind the bridge with one finger while playing the string normally. This is similar to a technique used in Japanese koto playing. For faster chromatic pieces a pitch shifter can be used to make the instrument fully chromatic. This can be set to momentarily jump shift the entire instrument's tuning one half step up or down, or it can be set on continuous pitch shift change which enables playing the instrument in dobro, slide guitar, or pedal steel guitar styles. Since the Gravikord and the Gravi kora produce no conflicting acoustic sound, they can be played with guitar effects such as delay, distortion, reverb units, or wah wah pedals.

In 1988, Guitar Player Magazine published an article on the Gravikord, saying that "even though the Gravikord has a high tech, modern sculpture look, it actually has its roots in the African kora, a double strung harp polyrhythmic music, plus the sound of the Japanese koto, African kalimba (thumb piano) and the African kora [Grawi] began experimenting with bamboo double strung harps that would allow him to perform separate melodies or accompaniments with each hand. Influences range from jazz, Dixieland, to Balinese gamelan and American folk music." This article also included a technical description of the instrument as well as a patent drawing of the Gravikord. The Metropolitan Museum of Art included the Gravikord in the show "Enduring Rhythms" (New York City, October 3, 1996 – August 3, 1997). In an article about this exhibition in The New York Times, Rita Reif wrote "The show stoppers include a Gravikord, an electronically amplified stringed instrument that sounds like an earthy harp. In their shapes and sounds, Mr. Moore (curator of the show) said, these instruments also represent a kind of continuity in 'the layered rhythms, the mixed timbres, and all that movement which is so African.'" In March 2018, the Gravikord became a permanent exhibit in the museum's Andre Mertens Galleries for Musical Instruments. In 2000, Elvis Costello listed Gravikords, Whirlies and Pyrophones, a collection of recordings of experimental musical instruments, in a list of the finest 500 albums of all time.

The Gravikord has an entry in the Grove Dictionary of Musical Instruments. Other articles describing or referencing the Gravikord have appeared in the following publications: Curio Magazine, Daily News, Dirty Linen, Experimental Musical Instruments, Gravikords Whirlies & Pyrophones, New Sounds, Science News, Smithsonian Magazine, The New York Times, The Washington Post, and Vanity Fair, among others.