being played Accordions have many configurations and types. What may be easy to do with one type of accordion could be technically challenging or impossible with another, and proficiency with one layout may not translate to another. The most obvious difference between accordions is their right-hand sides.
Piano accordions use a piano-style
musical keyboard; button accordions use a buttonboard. Button accordions are furthermore differentiated by their usage of a
chromatic or
diatonic buttonboard for the right-hand side. Accordions may be either bisonoric, producing different
pitches depending on the direction of bellows movement, or unisonoric, producing the same pitch in both directions. Piano accordions are unisonoric.
Chromatic button accordions also tend to be unisonoric, while
diatonic button accordions tend to be bisonoric, though notable exceptions exist. Accordion size is not standardized, and may vary significantly from model to model. Accordions vary not only in their dimensions and weight, but also in the number of buttons or keys present in the right- and left-hand keyboards. For example, piano accordions may have as few as 8 bass buttons (two rows of four), or up to 140 (seven rows of twenty) or beyond. Accordions also vary by their
available registers and by their specific tuning and voicing. Despite these differences, all accordions share several common components.
Universal components Bellows {{Listen is the most recognizable part of the instrument, and the primary means of
articulation. The production of sound in an accordion is in direct proportion to the motion of the bellows by the player. In a sense, the role of the bellows can be compared to the role of moving a
violin's bow on bowed strings. For a more direct analogy, the bellows can be compared to the role of breathing for a singer. The bellows is located between the right- and left-hand keyboards, and is made from
pleated layers of cloth and cardboard, with added leather and metal. It is used to create pressure and vacuum, driving air across the internal
reeds and producing sound by their vibrations, applied pressure increases the volume. The keyboard touch is not
expressive and does not affect
dynamics: all expression is effected through the bellows. Bellows effects include: • Volume control, including swells and fades • Repeated short, rapid changes of direction ("bellows shake"), which has been popularized by musicians such as
Renato Borghetti (
gaucho music) and
Luiz Gonzaga, and extensively used in
Forró, called
resfulego in Brazil • Constant bellows motion while applying pressure at intervals • Constant bellows motion to produce clear tones with no resonance • Subtly changing the intonation to mimic the expressiveness of a singer • Using the bellows with the silent air button gives the sound of air moving ("whooshing"), which is sometimes used in contemporary compositions for this instrument
Body The accordion's body consists of two boxes, commonly made of wood, joined by the bellows. These boxes house reed chambers for the right- and left-hand keyboards. Each side has
grilles in order to facilitate the transmission of air in and out of the instrument and to allow the sound to project. The grille at the right-hand side is usually larger and is often shaped for decorative purposes. The right-hand keyboard is normally used for playing the melody and the left-hand one for playing the accompaniment; however, skilled players can reverse these roles and play melodies with the left hand. The size and weight of an accordion varies depending on its type, layout and playing range, which can be as small as to have only one or two rows of basses and a single
octave on the right-hand keyboard, to the most common 120-bass accordion and through to large and heavy 160-bass free-bass converter models.
Pallet mechanism The accordion is an
aerophone. The keyboard mechanisms of the instrument either enable the air flow, or disable it:
Variable components The term
accordion covers a wide range of instruments, with varying components. All instruments have reed ranks of some format, apart from reedless
digital accordions. Not all have switches to change registers or ranks, as some have only one treble register and one bass register. The most typical accordion is the piano accordion, which is used for many musical genres. Another type of accordion is the button accordion, which is used in musical traditions including Cajun, Conjunto and
Tejano music, Swiss and Slovenian-Austro-German Alpine music, and Argentinian tango music. The
Helikon-style accordion has multiple flared horns projecting out of the left side to strengthen the bass tone. The word "
Helikon" refers to a deep-pitched tuba.
Right-hand keyboard systems Different systems exist for the right-hand keyboard of an accordion, which is normally used for playing the melody (while it can also play chords). Some use a
button layout arranged in one way or another, while others use a
piano-style keyboard. Each system has different claimed benefits by those who prefer it. They are also used to define one accordion or another as a different "type": •
Chromatic button accordions and the
bayan, a Russian variant, use a buttonboard where notes are arranged
chromatically. Two major systems exist, referred to as the B-system and the C-system (there are also regional variants). Rarely, some chromatic button accordions have a decorative right-hand keyboard in addition to the rows of buttons, an approach used by the virtuoso accordionist
Pietro Frosini. •
Diatonic button accordions use a buttonboard designed around the notes of
diatonic scales in a small number of keys. The keys are often arranged in one row for each key available. Chromatic scales may be available by combining notes from different rows. The adjective "diatonic" is also commonly used to describe bisonic or bisonoric accordions—that is, instruments whose right-hand (and in some instances even bass) keys each sound two different notes depending on the direction of the bellows (for instance, producing major triad sequences while closing the bellows and dominant seventh or 7–9 while opening). Such is the case, for instance, with the Argentinian
bandoneon, the Slovenian-Austro-German
Steirische Harmonika, the Czech Heligonka Harmonika, the Italian
organetto, the Swiss
Schwyzerörgeli and the
Anglo concertina. •
Piano accordions use a
musical keyboard similar to a piano, at right angles to the cabinet, the tops of the keys inward toward the bellows. • The rarely used bass accordion has only a right-hand keyboard, with ranks of 8', 16', and 32' reeds, with the lowest note being the deepest pitch on a pipe organ
pedal keyboard (pedal C). It is intended for performing
basslines in accordion orchestras. • The rarely used piccolo accordion also has only a right-hand keyboard. •
6-plus-6 accordions use a buttonboard with three rows of buttons in a "uniform" or "whole-tone" arrangement, generally known as a
Jankó keyboard. The chromatic scale consists of two rows. The third row is a repetition of the first row, so there is the same fingering in all twelve scales. These accordions are produced only in special editions e.g. the
logicordion produced by
Harmona. Italian Button Accordion QM r.jpg|A button key accordion made by the company Marrazza in Italy. It was brought by Italian immigrants to Australia as a reminder of their homeland. PianoAccordeon.jpg|A
Weltmeister piano accordion by
VEB Klingenthaler Harmonikawerke Left-hand keyboard systems Different systems are also in use for the left-hand keyboard, which is normally used for playing the accompaniment. These usually use distinct bass buttons and often have buttons with concavities or studs to help the player navigate the layout despite not being able to see the buttons while playing. There are three general categories: • The
Stradella bass system, also called
standard bass, is arranged in a
circle of fifths and uses single buttons for bass notes and additional rows of single buttons for preset major, minor, dominant seventh, and diminished
chords. The dominant seventh and diminished chords are three-note chord voicings that omit the fifths of the chords. • The Belgian bass system is a variation used in Belgian chromatic accordions. It is also arranged in a circle of fifths but in reverse order. This system has three rows of basses, three rows of chord buttons allowing easier fingering for playing melodies, combined chords, better use of fingers one and five, and more space between the buttons. This system was rarely used outside of its native Belgium. • Various
free-bass systems for greater access to playing melodies and complex
basslines on the left-hand keyboard and to forming one's own chords note-by-note. These are often chosen for playing
jazz and
classical music. Some models can convert between free-bass and Stradella bass; this is called
converter bass. The free-bass left hand notes are arranged chromatically in three rows with one additional duplicate row of buttons. • Luttbeg double-keyboard piano accordions have a piano keyboard layout on both the treble and bass sides. This allows
pianists, most notably
Duke Ellington, to double up on the accordion without difficulty. The Bercandeon is an improved version of that instrument, also making it a "keyboard bandoneon". • In 2021, a patent was published by Valerio Chiovarelli for a new bass system called the "Chiovarelli Jazz System". This system is a variation of the Stradella bass system where, instead of triads, the chordal buttons of this system produce bichords (chords with only 2 pitches instead of 3). The "Chiovarellia Jazz System" (or "CJS" for short) prioritizes the effectiveness of left hand accordion in jazz music, hence the name of the system, but according to the inventor, these chords can be useful when playing many varieties of music.
Reed ranks and switches with closeup of reeds Inside the accordion are the reeds that generate the instrument tones. These are organized in different sounding
banks, which can be further combined into
registers producing differing
timbres. All but the smaller accordions are equipped with switches that control which combination of reed banks operate, organized from high to low
registers. Each register stop produces a separate sound timbre, many of which also differ in octaves or in how different octaves are combined. See the
accordion reed ranks and switches article for further explanation and audio samples. All but the smaller accordions usually have treble switches. The larger and more expensive accordions often also have bass switches to give options for the reed bank on the bass side.
Classification of chromatic and piano type accordions In describing or pricing an accordion, the first factor is size, expressed in number of keys on either side. For a piano type, this could for one example be 37/96, meaning 37 treble keys (three octaves plus one note) on the treble side and 96 bass keys. A second aspect of size is the width of the white keys, which means that even accordions with the same number of keys have keyboards of different lengths, ranging from for a child's accordion to for an adult-sized instrument. After size, the price and weight of an accordion is largely dependent on the number of reed ranks on either side, either on a
cassotto or not, and to a lesser degree on the number of combinations available through register switches. The next, but important, factor is the quality of the reeds, the highest grade called "a mano" (meaning "hand-made"), the next "tipo a mano" ("like hand-made"), lower grades including "export" and several more. Price is also affected by the use of costly woods, luxury decorations, and features such as a palm switch, grille mute, and so on. Some accordion makers sell a range of different models, from a less-expensive base model to a more costly luxury model. Typically, the register switches are described as
Reeds: 5 + 3, meaning five reeds on the treble side and three on the bass, and
Registers: 13 + M, 7, meaning 13 register buttons on the treble side plus a special "master" that activates all ranks, like the "tutti" or "full organ" switch on an organ, and seven register switches on the bass side. Another factor affecting the price is the presence of electronics, such as condenser microphones, volume and tone controls, or MIDI sensors and connections. , Ecuador
Straps The larger piano and chromatic button accordions are usually heavier than other smaller
squeezeboxes, and are equipped with two shoulder straps to make it easier to balance the weight and increase bellows control while sitting, and avoid dropping the instrument while standing. Other accordions, such as the
diatonic button accordion, have only a single shoulder strap and a right hand thumb strap. All accordions have a (mostly adjustable) leather strap on the left-hand side to keep the player's hand in position while drawing the bellows. There are also straps above and below the bellows to keep it securely closed when the instrument is not being played.
Electronic and digital In the 2010s, a range of electronic and digital accordions were introduced. They have an electronic
sound module which creates the accordion sound, and most use
MIDI systems to encode the keypresses and transmit them to the sound module. A digital accordion can have hundreds of sounds, which can include different types of accordions and even non-accordion sounds, such as pipe organ, piano, or guitar. Sensors are used on the buttons and keys, such as magnetic reed switches. Sensors are also used on the bellows to transmit the pushing and pulling of the bellows to the sound module. Digital accordions may have features not found in acoustic instruments, such as a piano-style
sustain pedal, a modulation control for changing keys, and a
portamento effect. As an electronic instrument, these types of accordions are plugged into a
PA system or
keyboard amplifier to produce sound. Some digital accordions have a small internal speaker and amplifier, so they can be used without a PA system or keyboard amplifier, at least for practicing and small venues like
coffeehouses. One benefit of electronic accordions is that they can be practiced with headphones, making them inaudible to other people nearby. On a digital accordion, the volume of the right-hand keyboard and the left-hand buttons can be independently adjusted. Acoustic-digital hybrid accordions also exist. They are acoustic accordions (with reeds, bellows, and so on), but they also contain sensors, electronics, and MIDI connections, which provides a wider range of sound options. An acoustic-digital hybrid may be manufactured in this form, or it may be an acoustic accordion which has had aftermarket electronics sensors and connections added. Several companies sell aftermarket electronics kits, but they are typically installed by professional accordion technicians, because of the complex and delicate nature of the internal parts of an accordion.
Unusual accordions Various hybrid accordions have been created between instruments of different buttonboards and actions. Many remain curiosities – only a few have remained in use: • The
Schrammel accordion, used in
Viennese chamber music and
klezmer, which has the treble buttonboard of a chromatic button accordion and a bisonoric bass buttonboard, similar to an expanded diatonic button accordion • The
Steirische Harmonika, a type of bisonoric diatonic button accordion particular to the Alpine folk music of Slovenia, Austria, the Czech Republic, the German state of Bavaria, and the Italian South Tyrol • The
schwyzerörgeli or Swiss organ, which usually has a three-row diatonic treble and 18 unisonoric bass buttons in a bass/chord arrangement – a subset of the Stradella system in reverse order like the Belgian bass – that travel parallel to the bellows motion • The
trikitixa of the
Basque people, which has a two-row diatonic, bisonoric treble and a 12-button diatonic unisonoric bass • The British chromatic accordion, the favoured diatonic accordion in Scotland. While the right hand is bisonoric, the left hand follows the Stradella system. The elite form of this instrument is generally considered the German manufactured Shand Morino, produced by
Hohner with the input of
Sir Jimmy Shand •
Pedal harmony, a type of accordion used sometimes in Polish folk music, which has a pair of
pump organ-like bellows attached. • The Finnish composer and accordionist Veli Kujala developed a
quarter tone accordion together with the Italian accordion manufacturer Pigini in 2005, and has written works for it. It deploys the same system as the concert accordion, with a scale of five octaves, each divided into 24 quarter tones. Other notable composers who have written
concertos for the quarter tone accordion include
Jukka Tiensuu and
Sampo Haapamäki. ==Manufacturing process==