Excitation of String Instruments
Melville Clark, Daniel Schwartz, W. C. Feldman · The Journal of the Acoustical Society of America · 1961
Stroboscopic lights and cameras are utilized to photograph the excitation and motion of piano, violin, and harp strings; high speed pictures of which will be shown. Fingers after plucking harp strings are not hit by the string, the shape of which may be easily computed. The wave character may be easily seen from the persistence of waveshape. Piano hammers hitting wound strings oscillate in the plane of the shank and hammer. The contact time (2–7 msec) is relatively independent of the speed of depression and frequency of the note (C1–C5). The piano action itself works much faster than it could be played. Very slight painting of a wound string greatly damps the sound. Terminal hammer speeds vary from 30 to 600 msec. The bow pulls the string aside without slipping. The return of the previously created pulse, reflected and inverted at the nut, snaps the string away from the bow in 15 of a period. The string deflects an equal and opposite amount before being picked up and replucked by the bow again. (This work was performed in Professor Harold Edgerton's laboratory and was supported by the National Association of Music Merchants.)