Instruments Beyond the Familiar
Close your eyes during an orchestral performance or an atmospheric film score, and you can usually recognize the familiar families: horsehair across violin strings, air reed-vibrating inside an oboe, or felt hammers striking piano wire. Yet some of the most unforgettable moments in recorded music arrive when a listener hears a sound and cannot picture what physical object could possibly be making it.
Musicologists use the Sachs-Hornbostel system (created by Curt Sachs and Erich Moritz von Hornbostel in 1914) to classify every instrument on Earth by what actually vibrates: strings (chordophones), air columns (aerophones), stretched skins (membranophones), the solid body of the instrument itself (idiophones), or electrical circuits (electrophones). Below, we look inside five extraordinary instruments that bend those boundaries.
The Ondes Martenot (France, 1928)
When French cellist and former World War I military radio operator Maurice Martenot unveiled the Ondes Martenot at the Paris Opera in April 1928, audiences heard something uncanny: an electronic voice that could weep, sigh, and vibrate with the expressive nuance of a bowed cello. While Leon Theremin's earlier invention required waving hands in mid-air without physical landmarks, Martenot gave players tactile control.
Beneath its seven-octave keyboard sits a taut wire ribbon connected to a variable capacitor. By slipping a small metal ring (the bague) onto the right index finger, the performer slides horizontally along the ribbon to produce continuous glissandi and subtle pitch vibrato, while the left hand sits in a drawer controlling a pressure-sensitive wooden key (the touche d'intensité) made with a small bag of conductive carbon powder. Pressing harder swells the volume from a whisper to an orchestral roar.
Even more fascinating are its acoustic speakers, called diffuseurs. One speaker, the metallique, mounts an actual bronze gong in front of the voice coil so electronic notes set metal shimmering; another, the palme, stretches twelve tuned strings across a wooden harp chamber so every electronic note awakens real acoustic sympathetic vibrations. You can hear it soaring through Olivier Messiaen's 1949 Turangalîla-Symphonie, Jacques Brel's "Ne me quitte pas," and Jonny Greenwood's eerie string arrangements on Radiohead's "How to Disappear Completely."
The West African Kora (Senegal, Gambia, Mali)
First-time listeners who hear a solo recording by Malian master Toumani Diabaté or Gambian virtuoso Sona Jobarteh often assume two or three guitarists are playing in the room. In fact, a single musician is playing the kora, the traditional instrument of the Mandinka jali (griot) oral historians.
The kora is neither a lute nor a simple harp; organologists classify it as a double-row bridge-harp. Its body is a large half-calabash gourd covered in taut cowskin, pierced by a long rosewood neck. Twenty-one strings do not lie flat over a fretboard; instead, they pass through notches cut into the left and right sides of a tall, vertical wooden bridge standing on the skin resonator. The musician holds two vertical hand-posts with the middle, ring, and little fingers, leaving only the thumbs and index fingers free.
Because the pitches alternate between the left and right rows of strings, playing a simple ascending scale requires alternating left-right-left-right between the two hands. This geometry makes rapid interlocking polyrhythms effortless: the thumbs pluck a steady bass pattern called the kumbengo while the index fingers weave cascading melodic improvisations called birimintingo.
The Hurdy-Gurdy / Vielle à Roue (Medieval Europe)
Dating back to the 10th-century monastic organistrum depicted on the stone portico of the Cathedral of Santiago de Compostela in Spain, the hurdy-gurdy solves a question every violinist has faced: what if the bow never ran out of length?
A rosined wooden wheel, cranked steadily by the player's right hand, rubs from underneath against both melody strings and continuous low drone strings. With the left hand, the player presses wooden keys along a box on the neck; each key pushes a small wooden wedge (a tangent) sideways against the melody string to shorten its vibrating length and change the pitch.
What gives the French Auvergne and Bourbonnais hurdy-gurdy its unmistakable rhythmic snap is a tiny movable bridge shaped like a crouching dog—called the chien. One drone string rests on this asymmetric piece of bone or boxwood. When the player cranking the wheel gives a sharp flick of the wrist (a coup de poignet), the extra string tension lifts the chien by a fraction of a millimeter, making it chatter rapidly against the spruce soundboard like a miniature snare drum synchronized to the drone.
Benjamin Franklin's Glass Armonica & the Shona Mbira
Two more instruments demonstrate how small changes in material physics alter our perception of space and pitch:
- The Glass Armonica (1761): After hearing composer Richard Pockrich play tunes by rubbing the rims of water-filled wineglasses in London, Benjamin Franklin worked with glassblower Charles James to nest thirty-seven blown-glass bowls of graduated sizes horizontally on an iron spindle turned by a foot treadle. Because the bowls are tuned by their diameter and wall thickness, they require no water. Moistened fingers touch the spinning rims, producing pure sine-like tones with almost no directional attack—making it difficult for the human ear to pinpoint where in the room the sound originates. Wolfgang Amadeus Mozart composed his 1791 Adagio and Rondo in C minor (K. 617) specifically for blind glass-armonica virtuoso Marianne Kirchgessner.
- The Mbira Dzavadzimu (Zimbabwe): Often mislabeled a simple "thumb piano," the sacred twenty-two-to-twenty-eight-key Shona instrument mounts forged metal tines onto a hardwood soundboard (gwariva) placed inside a large calabash gourd (deze). Crucially, snail shells or bottle caps are wired around the rim of the gourd. When a metal key is plucked, the shells buzz sympathetically. Far from being unwanted noise, this buzz (machachara) enriches the acoustic overtones so listeners can hear subtle ghost-melodies emerging out of two interlocking parts—kushaura (to lead) and kutsinhira (to weave behind).