Hurdy-Gurdy

The instrument from above, tail on the left: the wheel turning under the six strings, the chanterelles running through the keybox to the nut, and the drones out at the sides. The tangent of the highest key held stops the chanterelles (the dot): the wheel then sits further along the shorter string. A drone switched off is hooked away from the wheel. The trompette crosses the chien, drawn tilting as it lifts (much enlarged).

Below: the trompette's pull on the chien over the last 20 ms, a sawtooth once a period as the string sticks to the wheel and slips back, and the tirant's pull (dashed) holding the foot down. Above: the foot's lift off the soundboard. When the sawtooth's peak beats the tirant, the chien jumps and lands once a period, or rattles several times: the buzz.

The wheel's speed over the last six seconds, in turns a second. Above the dashed line the trompette's pull beats the tirant and the chien buzzes (shaded where it did). Each coup of the wrist is a surge across the line: their rhythm is the buzz's.

The melody's harmonics sit over the drones'. Missing harmonics near every 1/β-th are where the wheel sits: they move down as the tangent shortens the string. A buzz fills the gaps with the chien's clatter at the trompette's period.

The drones run on as steady lines while the melody steps above them. Each coup is a band of broadband buzz across the top of the picture, in time with the hand.