STRINGED MUSICAL INSTRUMENTS PLAYED BY BOWING AND BY PLUCKING Russian patent published in 2002 - IPC

FIELD: musical instruments. SUBSTANCE: history of evolution of bow and plucking stringed instruments using strings and sounding board for sound extraction and amplification may be dated to first century A.D. For instance, back in 1200 during construction of Sofia Cathedral in Novgorod resonance pots of different sizes with openings from pots and walls (so-called resonators) were built in walls under dome to attain better acoustics. Information is still available about stringed instruments using two separate sounding boards to amplify and improve their sounding which resemble resonating units of Sofia Cathedral. In search of better sounding and volume stringed instruments were altered in the course of their evolution as far as their shape ad material chosen for resonator, sounding board, finger-board, etc. are concerned. Stradivari in Italy, Batist Villiam in France, Andrei Batov (violin) and Krasnoshchekov (guitar) in Russia have greatly contributed to this evolution. Best sounding stringed instruments of to-day have ebony finger-board that joins string tensioning head with resonating unit above which strings are passed from head. Resonating unit has two sounding boards, upper one being made of spruce and lower, of ash, both joined together by shaped ferrule. Upper sounding board mounts resonator in the form of round opening like in guitar or in the form of two slits (ridges) like in violin. Strings above upper sounding board are supported by bridge that also functions in some instruments such as guitar as string attachment member. Setting strings in vibration by bowing or by plucking transforms longitudinal vibrations of upper sounding board by means of bridge into transverse vibrations of upper sounding board that forms a number of resonance-tuned circuits together with lower sounding board, their number governing range of musical expression of instrument. Ideal resonating unit should resonate at all frequencies of scale. So resonance of guitar should be provided at frequencies from D within counter-octave to D in second octave. Violin scale is narrower but it is shifted to higher frequencies, and so on. Thus instrument volume mainly depends on degree of transformation of longitudinal vibrations of strings into transverse vibrations of sounding board by means of bridge.. This transformation ratio is not over fractions of unity. Musical range of instrument expression depends on number of resonance-tuned circuits of sounding board corresponding to its scale. Frequency at resonance is found from formula ω_p, where m is sounding board mass; C is sounding board stiffness, N, as measured in units of SI system (Burdin, Handbook on International System of Units). Therefore equality of upper sounding board G/m = lower sounding board G/m should be satisfied for resonance tuning of upper and lower sounding boards. However resonating units of modern stringed instruments meet this condition only in vicinity of resonator and bridge where adequate mass and stiffness of upper sounding board increased due to opening and bridge correspond to mass and increased stiffness of lower sounding board made of ash whose density is higher than that of fur-tree used for upper deck. Remaining part of upper and lower sounding boards do not meet resonance condition, that is, they form sound dips in instrument scale. We propose stringed instrument played by bowing or by plucking (it may be violin, violoncello, contrabass, guitar, and the like) whose sounding-board transformation ratio is almost unity and its upper and lower sounding boards are matched in part-by-part manner throughout entire area scale frequency resonance. High transformation ratio is attained due to increasing height of bridge connected to rocking board, both transmitting longitudinal vibrations of strings to lower sounding board as bridge is secured at its bottom end to lower sounding board or to its spring and its elongated part is joined to rocking stop abutting against transverse spring or against crosspiece between ferrules near lower sounding board. Condition of resonance-tuned sounding boards is satisfied due to transferring resonator openings to bridge area, satisfying upper sounding board = lower sounding board equality, and due to ensuring this condition in vicinity of resonator crossed by bridge , as well as due to installation of bezel-horn on resonator opening. EFFECT: improved ratio of transforming longitudinal vibrations of instrument strings into transverse vibrations of its sounding board. 6 cl, 4 dwg