String instrument rosin than players of lower-pitched instruments, who tend to favor darker, softer rosin. The ravanahatha is one of the oldest string instruments. Ancestors of the modern bowed string instruments are the rebab of the Islamic Empires, the Persian kamanche and the Byzantine lira. Other bowed instruments are the rebec, hardingfele, nyckelharpa, kokyū, erhu, igil, sarangi and K'ni. The hurdy-gurdy is bowed by a wheel. Rarely, the guitar has been played with a bow (rather than plucked) for unique effects. The third common method of sound production in stringed instruments is to strike the string. The piano and hammered dulcimer use
Hurdy-gurdy a common bridge, and a relatively small wheel. Due to its size, the organistrum was played by two people, one of whom turned the crank while the other pulled the keys upward. Pulling keys upward is cumbersome, so only slow tunes could be played on the organistrum. The pitches on the organistrum were set according to Pythagorean temperament and the instrument was primarily used in monastic and church settings to accompany choral music. Abbot Odo of Cluny (died 942) is supposed to have written a short description of the construction of the organistrum entitled "Quomodo organistrum construatur" (How the Organistrum