String instrument strings, or play them by rolling the bell of a brass instrument such as a trombone on the array of strings. However, these are relatively rarely used special techniques. Other keyed string instruments, small enough for a strolling musician to play, include the plucked autoharp, the bowed nyckelharpa, and the hurdy-gurdy, which is played by cranking a rosined wheel. Steel-stringed instruments (such as the guitar, bass, violin, etc.) can be played using a magnetic field. An E-Bow is a small hand-held battery-powered device that magnetically excites the strings of an electric string instrument to provide a sustained, singing tone reminiscent
Viola organista his notebooks of 1488–1489 and in the drawings in the Codex Atlanticus and Manuscript H. In the first model the friction of the strings was achieved by a mechanical bow traveling sideways. The second model featured a single rotating wheel, similar to that of the earlier hurdy-gurdy, to play strings. It differs in that a hurdy-gurdy has a small number of strings that are constantly in contact with the wheel, rather than a larger number of strings that can be lowered onto the wheel. A hurdy-gurdy has a keybox with tangents that change the pitches of the strings, rather like