The flexatone (also written flex-a-tone or flex a tone) is a variable-pitch percussion instrument that produces a metallic, ghostly glissando sound instantly recognisable to anyone who has ever watched a classic horror movie or vintage cartoon. Despite its simple appearance, it has a fascinating history and a genuine place in 20th-century concert music.
Structurally, the flexatone consists of a thin elastic steel sheet held at one end by a metal handle, with two hard rubber balls mounted on wire arms on either side. Shaking the instrument causes the balls to strike alternately both faces of the sheet in rapid succession. The key element is the free thumb: pressing it on the free end of the sheet increases tension and raises pitch; releasing it lowers the pitch again.
The flexatone was invented and patented in the early 1920s, approximately 1922-1924, in the United Kingdom. The original patent was filed under the name Flex-a-tone and the instrument quickly crossed the Atlantic to the American market. At its launch it was considered a modern, revolutionary novelty instrument, perfectly in keeping with the spirit of the Roaring Twenties.
The flexatone's golden age spanned the 1920s through 1960s. During this period, avant-garde composers were experimenting with new timbres. The flexatone found champions in both popular music (jazz, big band, vaudeville) and serious contemporary concert music.
It was Armenian composer Aram Khachaturian who gave the instrument its greatest moment of prestige in classical music, incorporating it prominently in his Piano Concerto (1936). Arnold Schoenberg also prescribed it in his Suite Op. 29 (1926), establishing the flexatone as a legitimate part of the 20th-century orchestral palette. In Hollywood, composer Carl Stalling deployed it constantly in Warner Bros. cartoons and film scores from the 1930s to the 1950s.
The physics are elegantly simple. A metal sheet's vibration frequency depends on its effective free length: the shorter the vibrating portion, the higher the pitch. Pressing the thumb on the free end of the sheet reduces the vibrating length and raises pitch; releasing it returns the sheet to its full length and lowers pitch.
The two rubber balls act as the excitation mechanism — the equivalent of a violin bow or a xylophone mallet. Shaking the instrument causes the balls to oscillate by inertia and strike alternately both faces of the sheet, sustaining its vibration. Shaking speed affects volume but not pitch.
Getting your first sounds from a flexatone takes under five minutes. Achieving precise melodic pitch control requires months of practice.
Hand position: Hold the handle between two fingers, keeping your thumb completely free to reach the sheet. Shake with a quick horizontal wrist motion — not the whole arm. Varying thumb pressure while shaking creates smooth glissandos up and down.
Start with just the glissando effect: press your thumb all the way down, then slowly release while shaking. You will hear the iconic descending wail. Reverse it. Once you can control up and down glissandos, try holding a single stable pitch for 3 seconds — that is the first real challenge of the flexatone.
If the flexatone has a spiritual home, it is Hollywood. During the 1930s-50s, film and animation composers discovered it was perfectly suited for two opposite purposes: creating suspense and horror, or underlining comic and absurd moments.
In golden-age cartoons (Looney Tunes, Tom & Jerry, Merrie Melodies), composer Carl Stalling used the flexatone repeatedly for accelerated chases, falls, ghost appearances and moments of total confusion. That iconic "cartoon spring" sound everyone knows from vintage animation is largely the flexatone.
Beyond cinema, the flexatone appears in significant 20th-century concert works:
| Composer | Work | Year | Role |
|---|---|---|---|
| Aram Khachaturian | Piano Concerto | 1936 | Featured soloist, lyrical passages |
| Arnold Schoenberg | Suite Op. 29 | 1926 | Chamber orchestra instrument |
| Dmitri Shostakovich | Jazz Suite No. 1 | 1934 | Orchestral colour in jazz section |
| George Crumb | Black Angels | 1970 | Extreme tension timbral effect |
| Carl Stalling | Warner Bros. Cartoon Music | 1936-1958 | Recurring comic and sonic effects |
| Feature | Flexatone | Theremin |
|---|---|---|
| Type | Acoustic percussion | Electronic |
| Physical contact | Yes — shaken and pressed | No — contactless |
| Pitch range | ~2.5 octaves | 5+ octaves |
| Entry price | £8-15 (basic) | £200-500 (basic) |
| Portability | Very high (pocket-sized) | Medium (needs power) |
| Learning curve | Low (effects) / medium (melody) | Very high |
| Timbre | Metallic, percussive, raw | Soft, ethereal, vocal |
For more on the theremin, read our complete guide: Best theremin for beginners.
The easiest option. Search for "flexatone" and look for brands like Stagg, LP (Latin Percussion), Sonor or Tycoon. Prices range from £10 to £40.
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A variable-pitch metal percussion instrument: a flexible steel sheet with two rubber balls that strike it when shaken. The thumb controls sheet tension to vary pitch, producing a characteristic metallic glissando.
Its unstable, eerie glissando sound — like a supernatural voice searching for its note — was discovered by Hollywood composers in the 1930s-40s as perfect for evoking tension and the supernatural. It became a standard effect in the golden age of cinema and animation.
Basic effects (glissandos, general high/low pitch) are very easy. Playing precisely pitched melodies requires practice since the relationship between thumb pressure and pitch varies by instrument. Great for improvisation and experimentation from day one.
Yes. Aram Khachaturian featured the flexatone as a prominent soloist in his Piano Concerto of 1936, one of the most performed 20th-century orchestral concertos. It is the most celebrated use of the flexatone in concert music.