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
Hurdy-gurdy either "un glissé" (a slide) or "une trainée" (a streak). On the Hungarian "tekerő" the same control is achieved by using a wedge called the "recsegőék" (control wedge, or literally "buzzer wedge") that pushes the drone string downward. In traditional "tekerő" playing, the buzzing bridge is controlled entirely by the wrist of the player and has a very different sound and rhythmic possibilities from those available on French instruments. Regional types of hurdy-gurdies since the Renaissance can also be classified based on wheel size and the presence or absence (and type) of a buzzing bridge. The following description of various