The 100-String Zither That Can Mimic Water and Thunder
Dating back millennia in Persian music, the santur is a trapezoidal hammered dulcimer strung with dozens of metal wires—typically 72 strings grouped into courses of four. Musicians strike the strings using delicate wooden mallets known as mezrab. Because each note rings out on multiple tightly tuned brass and steel wires, skilled players can evoke rainfall, thunderclaps, and echoing vocal tones.
Anatomy of a Trapezoidal Resonator
The santur is classified as a struck chordophone, or hammered box zither, recognizable by its distinct trapezoidal soundboard. Traditionally crafted from aged hardwoods such as walnut, rosewood, or betel palm, the hollow wooden box must possess extraordinary structural integrity. It sustains tremendous tension from dozens of taut metal wires anchored along its angled flanks. Inside the box, a series of sound posts and braces distribute this downward load, ensuring that the delicate wooden top plate does not buckle under the collective pull of the strings while still vibrating freely to project acoustic energy.
A standard Iranian santur features seventy-two strings arranged in groups of four, known as courses. Each course is tuned in strict unison, meaning that four individual wires sound as a single, uniform pitch when struck. The strings are divided by metal composition: the lower register utilizes bronze or brass wires, which produce warmer, darker undertones, while the higher registers use drawn steel strings that yield crisp, brilliant treble frequencies. On the soundboard, two pierced rosettes or sound holes allow air inside the acoustic chamber to circulate and escape, deepening the instrument's sustained resonance.
Sound transmission relies on two offset rows of small, movable wooden bridges called kharak. In a standard instrument, nine bridges are set on the right side and nine on the left. The steel strings pass directly over the left row of bridges, which bisects each wire into two playable segments sounding an octave apart. The brass strings pass over the right row of bridges, vibrating along their full playable length to generate the bass notes. This geometric arrangement yields three distinct melodic registers—bass, tenor, and treble—all arranged across a relatively compact wooden surface.