Gravi-kora

The gravikord is a modern, 24 string, electric double bridge-harp invented by Robert Grawi in 1986, which is closely related to both the West African kora and the kalimba. 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. There is a similar instrument, also developed by Grawi, the gravi-kora, which is tuned identically to a traditional 21 string African kora.

The gravikord is a new instrument developed on the basis of 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. Two handles located in elevation near the middle of the bridge allow holding the instrument. 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. The tuning of the gravikord is not the same as a traditional Kora, and playing techniques are not directly compatible.

Because of the deep cultural significance of cross-rhythms to Sub-Saharan African music, several instruments have evolved there which are constructed in such a way as to more easily generate cross-rhythms. These instruments organize the notes in a uniquely divided alternate array – not in the straight linear bass to treble structure that is so common to many western instruments such as the piano, harp, marimba, etc.... Instruments such as the West African kora, and Doussn'gouni, part of the harp-lute family of instruments, and thumb piano type instruments such as the kalimba and mbira also have this separated double tonal array structure.

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