Harmonica
The harmonica, also known as a French 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. The harmonica is played by using the lips and tongue 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 type of harmonica is a
diatonic Richter-tuned instrument with ten air passages and twenty reeds, often called a blues harp. The 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, the reed alternately blocks and unblocks the airway to produce sound.
Reeds are tuned to individual pitches. Tuning may involve changing a reed's length, how heavy it is near its free end, or how stiff it is near its fixed end. Reeds that are longer, heavier, or more flexible produce lower pitches; shorter, lighter, or stiffer reeds produce higher pitches. If, as on most modern harmonicas, a reed is affixed above or below its slot rather than in the plane of the slot, it responds more easily to air flowing in the direction that initially would push it into the slot, i.e., as a closing reed. This difference in response to air direction makes it possible to include both a blow reed and a draw reed in the same air chamber, and to play them separately without relying on flaps of plastic or leather to block the nonplaying reed.
An important technique in performance is bending, causing a drop in pitch by making embouchure adjustments. Bending the pitch of an isolated reed is possible on chromatic models, but it is also possible to lower or raise the pitch produced by pairs of reeds in the same chamber, as on a diatonic or other unvalved harmonica. Such two-reed pitch changes actually involve sound production by the normally silent reed, the opening reed.
Parts
The basic parts of the harmonica are the comb, reed plates, and cover plates.Comb
The comb is the main body of the instrument, which, when assembled with the reed plates, forms air chambers for the reeds. The term "comb" may originate from the similarity between this part of a harmonica and a hair comb. Harmonica combs were traditionally made from wood, but now are also made from plastic or metal. Some modern and experimental comb designs are complex in the way that they direct the air.Dispute exists among players about whether comb material affects the tone of a harmonica. Those saying no argue that unlike the soundboard of a piano or the top piece of a violin or guitar, a harmonica's comb is neither large enough nor able to vibrate freely enough to substantially augment or change the sound. Among those saying yes are those who are convinced by their ears. Few dispute that comb surface smoothness and air tightness when mated with the reed plates can greatly affect tone and playability. The main advantage of a particular comb material over another one is its durability. In particular, a wooden comb can absorb moisture from the player's breath and contact with the tongue. This can cause the comb to expand slightly, making the instrument uncomfortable to play, and to then contract, potentially compromising air tightness. Various types of wood and treatments have been devised to reduce the degree of this problem.
An even more serious problem with wooden combs, especially in chromatic harmonicas, is that, as the combs expand and shrink over time, cracks can form in the combs, because the comb is held immobile by nails, resulting in disabling leakage. Serious players devote significant effort to restoring wood combs and sealing leaks. Some players used to soak wooden-combed harmonicas in water to cause a slight expansion, which they intended to make the seal between the comb, reed plates, and covers more airtight. Modern wooden-combed harmonicas are less prone to swelling and contracting, but modern players still dip their harmonicas in water for the way it affects tone and ease of bending notes.
Reed plate
The reed plate is a grouping of several reeds in a single housing. The reeds are usually made of brass, but steel, aluminium, and plastic are occasionally used. Individual reeds are usually riveted to the reed plate, but they may also be welded or screwed in place. Reeds fixed on the inner side of the reed plate respond to blowing, while those fixed on the outer side respond to suction.Most harmonicas are constructed with the reed plates screwed or bolted to the comb or each other. A few brands still use the traditional method of nailing the reed plates to the comb. Some experimental and rare harmonicas also have had the reed plates held in place by tension, such as the WWII-era all-American models. If the plates are bolted to the comb, the reed plates can be replaced individually. This is useful because the reeds eventually go out of tune through normal use, and certain notes of the scale can fail more quickly than others.
A notable exception to the traditional reed plate design is the all-plastic harmonicas designed by Finn Magnus in the 1950s, in which the reed and reed plate were molded out of a single piece of plastic. The Magnus design had the reeds, reed plates, and comb made of plastic and either molded or permanently glued together.
Cover plates
Cover plates cover the reed plates and are usually made of metal, though wood and plastic have also been used. The choice of these is personal; because they project sound, they determine the tonal quality of the harmonica. Two types of cover plates are used: traditional open designs of stamped metal or plastic, which are simply there to be held; and enclosed designs, which offer a louder tonal quality. From these two basic types, a few modern designs have been created, such as the Hohner CBH-2016 chromatic and the Suzuki Overdrive diatonic, which have complex covers that allow for specific functions not usually available in the traditional design. In the late 19th and early 20th centuries, harmonicas not uncommonly had special features on the covers, such as bells, which could be rung by pushing a button.Wind-savers
Wind-savers are one-way valves made from thin strips of plastic, knit paper, leather, or Teflon glued to the reed plate. They are typically found in chromatic harmonicas, chord harmonicas, and many octave-tuned harmonicas. Wind-savers are used when two reeds share a cell and leakage through the nonplaying reed would be significant. For example, when a draw note is played, the valve on the blow reed-slot is sucked shut, preventing air from leaking through the inactive blow reed. An exception to this is the now-discontinued Hohner XB-40, on which valves are placed not to isolate single reeds, but rather to isolate entire chambers from being active, a design that made playing traditional blues bends possible on all reeds.Mouthpiece
The mouthpiece is placed between the air chambers of the instrument and the player's mouth. This can be integral with the comb ; part of the cover ; or may be a separate unit, secured by screws, which is typical of chromatics. In many harmonicas, the mouthpiece is purely an ergonomic aid designed to make playing more comfortable. In the traditional slider-based chromatic harmonica, it is essential to the functioning of the instrument because it provides a groove for the slide.Accessories
Amplification devices
Since the 1950s, many blues harmonica players have amplified their instrument with microphones and tube amplifiers. One of the early innovators of this approach was Marion "Little Walter" Jacobs, who played the harmonica near a "Bullet" microphone marketed for use by radio taxi dispatchers. This gave his harmonica tone a "punchy" midrange sound that could be heard above an electric guitar. Also, tube amplifiers produce a natural growling overdrive when cranked at higher volumes, which adds body, fullness, and "grit" to the sound. Little Walter also cupped his hands around the instrument to create a kind of flexible chamber, giving it a powerful, distorted sound somewhat reminiscent of a saxophone, hence the term "Mississippi saxophone". Some harmonica players in folk use a regular vocal microphone, such as a Shure SM 58, for their harmonica, which gives a clean, natural sound.As technology in amplification has progressed, harmonica players have introduced other effects units to their rigs, as well, such as reverb, tremolo, delay, octave, additional overdrive pedals, and chorus effect. John Popper of Blues Traveler uses a customized microphone that encapsulates several of these effects into one handheld unit, as opposed to several units in sequence. Many harmonica players still prefer tube amplifiers to solid-state ones, owing to the perceived difference in tone generated by the vacuum tubes. Players perceive tubes as having a "warmer" tone and a more "natural" overdrive sound. Many amplifiers designed for electric guitar are also used by harmonica players, such as the Kalamazoo Model Two, Fender Bassman, and the Danelectro Commando. Some expensive handmade boutique amplifiers are built from the ground up with characteristics that are optimal for amplified harmonica.