The harmonica, also known as a French harp, mouth harp or mouth organ, is a free reed wind instrument used worldwide in many musical genres, notably in blues, American folk music, classical music, jazz, country, and rock. The many types of harmonica include diatonic, chromatic, tremolo, octave, orchestral, and bass versions. A harmonica is played by using the mouth to direct air into or out of one holes along a mouthpiece. Behind each hole is a chamber containing at least one reed. The most common is the
diatonic Richter-tuned with ten air passages and twenty reeds, often called the blues harp. A harmonica reed is a flat, elongated spring typically made of brass, stainless steel, or bronze, which is secured at one end over a slot that serves as an airway. When the free end is made to vibrate by the player's air, it alternately blocks and unblocks the airway to produce sound.
A 16-hole chromatic (top) and 10-hole diatonic harmonica
Comb and two reed plates
Reed plate
Reed plate mounted on the comb of a diatonic harmonica, one of several categories of harmonica
A free reed aerophone is a musical instrument that produces sound as air flows past a vibrating reed in a frame. Air pressure is typically generated by breath or with a bellows. In the Hornbostel–Sachs system, it is number: 412.13. Free reed instruments are contrasted with non-free or enclosed reed instruments, where the timbre is fully or partially dependent on the shape of the instrument body, Hornbostel–Sachs number: 42.
The reeds of an early 20th-century button accordion, with closeup
Sheng with 17 pipes; height is 55 cm (22 inches)
Free reed from a Melodion, 1867