One of Ernst Chladni's (1756 - 1827) best-known achievements was inventing a technique to show the various modes of vibration of a rigid surface. When resonating, a plate or membrane becomes divided into areas that vibrate freely, bounded by nodal lines where no vibration occurs.
Chladni repeated the pioneering experiments of Robert Hooke who, in 1680, had observed the nodal patterns associated with the vibrations of glass plates. Hooke ran a violin bow along the edge of a plate covered with flour and saw the nodal patterns emerge.
Several strings under tension are stretched over two bridges, one at each end of a hollow box. The string tension can be altered to adjust their tuning. The strings vibrate in the wind at the frequencies (pitches) of the natural harmonic series.
The harp is subject to the von Karman vortex street effect: the motion of the wind across a string causes periodic vortices downwind and these alternating vortices make the string vibrate.
When a musical instrument creates a note you hear its fundamental frequency coloured by other, lesser tones, called harmonics. The aeolian harp produces no fundamental, just the harmonics. It is this property that creates its weird sound.
The Heaven's Breath sculpture's sound source is the wind. Naturally generated acoustic energy from this source is modified and mixed with a synthesised sound source, fed to a Chladni plate and thus converted to visible music.