Hurdy-gurdy
The hurdy-gurdy (Drehleier; ogranistrum; sinfonia) is a mechanised string instrument with one or more strings that run over a wheel driven by a crank. This rosined wheel takes the place of a bow and enables a continuous, uninterrupted tone. In addition to the melody string, which can be fretted and operated via a keyboard comparable to the playing of a monochord, there are one or more drone strings which produce a constant accompanying tone. Their function is comparable to that of the drone pipes of the bagpipes. It thus combines the principles of three significant instruments of the time into one: the monochord, the bow (from the vielle) and the keyboard (from the organ). The instrument can be found in illustrations from the 11th century onwards and comes in as many forms as it has names: particularly in its early days, hurdy-gurdies played by two musicians were common, with one turning the crank and the other working the keys (organistrum), whilst both might have sung along. In this form, it was also used for music lessons. From the 12th century onwards, hurdy-gurdies played by a single person became increasingly common. These included not only vielle-shaped models but also box-shaped ones, in which the inner workings are completely concealed under illustrations and allow fewer conclusions to be drawn about the construction (sinfonia). From the 14th century at the latest, the ‘trumpet string’ can also be found, which remains a characteristic of the sound of the traditional hurdy-gurdy to this day. Here, one of the drone strings runs over a bridge resting flexibly on the soundboard; when the wheel is turned vigorously, this causes the bridge to vibrate, producing a percussive sound. This enables the player to produce a rhythm in addition to the melody and drone accompaniment. The keyboards of medieval hurdy-gurdies were, like those of the harp and many other stringed instruments, presumably largely diatonic, although – as with the harp – the semitone positions of b-fa and b-mi, considered diatonic, may have been included in the scale.
The early hurdy-gurdy (sinfonia) on “Geschichtsfenster”: https://www.youtube.com/watch?v=mrAq5WLU91I&t=889s
The late hurdy-gurdy on “Geschichtsfenster”: https://www.youtube.com/watch?v=mrAq5WLU91I&t=5630s