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 end. It was around this time that "buzzing bridges" first appeared in illustrations. The buzzing bridge (commonly called the "dog") is an asymmetrical bridge that rests under a drone string on the sound board. When the wheel is accelerated, one foot of the bridge lifts from the soundboard and vibrates, creating a buzzing sound. The buzzing bridge is thought to have been borrowed from the "tromba marina" (monochord), a bowed string instrument. During the late Renaissance, two characteristic shapes of hurdy-gurdies developed. The first was guitar-shaped and the second had a rounded lute-type body made of staves. The lute-like body