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
Bowed clavier Bowed clavier The bowed clavier (', ' or " in German) is a keyboard instrument strung with gut strings, the tone of which is produced by a steadily revolving, well rosined cylinder powered by a foot pedal, a mechanism similar to that found in the hurdy-gurdy. The " was illustrated and described by Michael Praetorius in his treatise on musical instruments "Syntagma Musicum" II, in the section "De Organograhia", published 1614-20 in Germany. It was re-invented by Joh. Hohlfeld of Berlin in 1751. This instrument and another one of his inventions, a device that recorded keyboard improvisations in real time,