Cimbalom

One string of the last key's course as it moves now, its swing magnified, between its bridges, and the hammer where it lands. On the hammered dulcimer the treble bridge divides the string 2 : 3 and the far side rings along, a fifth away. The bar under the string turns red while the dampers are on it.

The last key's force on the bridge, in decibels, over the last eight seconds. Its strings start in step and drain into the bridge together, fast; as their small mistuning pulls them apart they stop driving it together, and the sound falls slower or beats. Perfect unisons give one straight line; a wide spread gives beats.

The force between the hammer and the strings, against time. Cotton stays on a millisecond or more and rises gently, so it leaves the upper partials out; bare wood jumps at once. A light hammer is thrown back early, often by the wave that returns from the near bridge, and a whippy stick can drive the head back for a second blow.

The partials are stretched a little by the wire's stiffness. Strike at the middle and the even ones vanish; near the bridge the fundamental weakens. On the dulcimer the far side's partials (the second colour) ring where they meet the struck side's.

The upper partials die first. With the dampers off (or the pedal down) every other course rings along, a haze of lines around each note.