1. Background

What Is an Aeolian Harp?

An aeolian harp (also known as a wind harp) is a stringed instrument that is played entirely by the wind. Named after Aeolus, the ancient Greek god of the wind, the instrument requires no human performer -- it simply needs to be placed where a steady current of air can flow across its strings.

The basic construction is straightforward: a set of strings, typically of varying thickness but often tuned to the same pitch, are stretched across a resonating body or frame. When wind passes over the strings, it creates a phenomenon known as vortex shedding -- tiny whirlpools of air (von Karman vortices) that peel alternately off opposite sides of the string. These oscillating pressure differences push and pull on the string, and when the frequency of the vortex shedding matches one of the string's natural resonant frequencies, the string begins to vibrate audibly. This is called "lock-in."

The sound of an aeolian harp is unlike any other instrument. Because the strings are excited by natural wind rather than deliberate plucking or bowing, the tones rise and fall organically with gusts and lulls. Strings may begin vibrating at one harmonic, then shift to another as the wind speed changes. Multiple strings vibrating simultaneously create rich, beating textures as their overtones interact. The result is an ethereal, constantly evolving soundscape that is both unpredictable and deeply musical.

How Wind Excites a String

The physics behind aeolian vibration rests on the Strouhal relationship: the frequency at which vortices peel off a string rises in proportion to the wind speed, and falls as the string gets thicker. As wind speed increases, the vortex shedding frequency rises, and when it aligns with one of the string's harmonics (fundamental, 2nd harmonic, 3rd harmonic, etc.), the string resonates and produces sound.

A crucial characteristic of aeolian excitation is that the lock-in window is relatively narrow. The wind speed must fall within a specific range for any given harmonic to be excited. This is why aeolian harps produce their distinctive shifting tones -- as the wind speed varies, different harmonics of different strings move in and out of their lock-in windows, creating a continuously changing texture. When the shedding frequency sits slightly off a harmonic rather than exactly on it, the drive and the string's resonance interfere to produce a slow, wind-dependent beating -- a gentle pulsing that shifts as the wind speed drifts, adding to the instrument's living quality.

Longer strings under higher tension have narrower lock-in windows (higher mechanical Q), meaning the wind must be more precisely tuned to excite them. Shorter, looser strings have wider windows and respond more easily. String material also plays a role: metal strings are bright and sustain longer, gut strings are warmer and more traditional, and nylon strings produce softer, darker tones.

About This Plugin

The Aeolian Wind Drone VST models these physical phenomena digitally, simulating 12 strings arranged in paired courses (like a 12-string guitar). Each string has its own vortex exciter responding to a shared wind simulation, and a digital waveguide string model that produces the resonant tone. The strings interact through sympathetic resonance, just as they would on a real harp, creating the complex interplay of overtones that gives aeolian harps their characteristic voice.

Plugin Formats

Aeolian Wind Drone installs as a VST3 plugin and a Standalone application on Windows, macOS, and Linux. On macOS it also installs as an Audio Unit (AU), so it appears in Logic Pro and GarageBand alongside VST3 hosts. Load whichever format your DAW prefers — every format is the same instrument and shares your presets.

Pro Tools (AAX) is not supported. The AAX format requires Avid's proprietary developer agreement and hardware-backed (PACE/iLok) signing, which are outside the scope of this project, so there is no Pro Tools build — and none is planned. Pro Tools users can run the plugin in a separate host or via a third-party VST3-to-AAX bridge, but that is not something we provide or support.