Instrument
Clarinet
A single-reed woodwind with an unusually wide range and smooth, rounded tone.
The clarinet, pictured above resting on its sheet music, uses a single reed — one thin strip of cane clamped against a fixed mouthpiece and set vibrating by the player's breath — producing a smoother, more rounded tone than the double-reed oboe and bassoon elsewhere in the woodwind family.
Among the woodwinds, the clarinet has an unusually wide range, and its tone color shifts noticeably across that range — dark and rich in its lowest register (the "chalumeau"), bright and clear at the top — which composers frequently exploit deliberately. It's also unusually agile for its size, capable of extremely fast passagework and wide leaps with relatively little strain.
The clarinet arrived later than the flute, oboe, and bassoon (invented around 1700, standardized through the 1700s), and Mozart was among the first major composers to write extensively and idiomatically for it, including his well-loved Clarinet Concerto.
Where to start listening: the opening clarinet glissando (a rapid upward slide) at the start of Gershwin's Rhapsody in Blue is one of the instrument's most famous entrances.